sk supreme cargo manual

Cargo Operating Manual

List of Contents:

Issue and UpdateMechanical Symbols and Colour SchemeElectrical Symbols and Abbreviations Introduction

Part 1: Design Concept of the Vessel

1.1 Principal Particulars1.1.1 Principal Particulars of the Ship1.1.2 Principal Particulars of the Cargo Machinery1.1.3 General Arrangement1.1.4 Tanks and Capacity Plan

1.2 Rules and Regulations

1.3 Design Concept of the Cargo System 1.3.1 Design Concept of the Cargo System 1.3.2 Membrane Cargo Containment

1.4 Hazardous Areas and Gas Dangerous Zone Plan

Illustrations1.1.3a General Arrangement1.1.3b General Arrangement Accommodation and

Engine Room Areas1.3.2a Membrane Cargo Containment (GTT Mark III)1.3.2b IBS IS Section of Transverse Corner1.3.2c IBS IS Flat Panel Junction1.4a Hazardous Areas and Gas Dangerous Zone Plan

Part 2: Properties of LNG

2.1 Properties of LNG 2.1.1 Physical Properties, Composition and

Characteristics of LNG

2.2 Characteristics of LNG and Definitions2.2.1 Flammability of Methane, Oxygen and

Nitrogen Mixtures2.2.2 Supplementary Characteristics

2.3 Health Hazards

Illustrations and Tables2.1a Physical Properties of LNG2.1b Composition of Qatar LNG

2.1c Properties of Methane2.1d Boiling Point of Methane with Pressure2.1e Relative Density of Methane and Air2.2.1a Flammability of Methane, Oxygen and

Nitrogen Mixtures2.2.2a Temperature and Steel Grades

Part 3: Integrated Automation System (IAS)

3.1 Centralised Administration and Control Centre (CACC) Arrangement

3.2 IAS (Integrated Automation System)3.2.1 IAS Overview3.2.2 IAS Universal Control Station Operation3.2.3 Cargo Part Displays and Operation Planning3.2.4 Personal Computer Network3.2.5 Extension Alarm System3.2.6 IAS Mimics3.2.7 Use of Ope Index, Guide and Flow Mimics

Illustrations3.2.1a IAS Overview3.2.1b IAS Operators Keyboard3.2.7a Use of Ope Index, Guide and Flow Mimics

Part 4: Cargo and Ballast System

4.1 Cargo Containment System

4.2 Cargo Piping System4.2.1 Liquid Line4.2.2 Vapour Line4.2.3 Spray Line4.2.4 Emergency Vent Line (One Tank Operation)4.2.5 Fuel Gas Line4.2.6 Vent Line4.2.7 Inerting/Aeration Line

4.3 Cargo Pumps 4.3.1 Main Cargo Pump4.3.2 Stripping/Spray Pump4.3.3 Emergency Cargo Pump

4.4 Cargo Compressors4.4.1 HD Compressor4.4.2 LD Compressor

4.5 Boil-Off/Warm-Up Heater 4.6 LNG Vaporizer

4.7 Forcing Vaporizer

4.8 Custody Transfer System4.8.1 Foxboro CTS4.8.2 Whessoe Float Level Gauge4.8.3 Trim/List Indicator

4.9 Nitrogen Generator

4.10 Inert Gas and Dry Air Generator

4.11 Fixed Gas Detection System

4.12 Cargo and Ballast Valve Control and Emergency Shut Down System4.12.1 Cargo and Ballast Valve Control System4.12.2 Emergency Shutdown and Cargo Tank

Protection Scheme4.12.3 Ship/Shore Link4.12.4 Mooring Load Monitor System

4.13 Total Boil-Off Gas Control System

4.14 Relief Systems4.14.1 Cargo Tank Relief Valves4.14.2 IBS/IS Relief Valves4.14.3 Line Relief Valve

4.15 Ballast Level and Draught Indicating System4.15.1 Ballast Piping4.15.2 Ballast Level and Draught Indicating System

Illustrations4.2a Cargo Piping System4.3.1a Main Cargo Pump4.3.1b Unloading Flow Diagram4.3.2a Stripping/Spray Pump4.3.2b Spray Start Sequence4.3.2c Spraying Control Start Sequence4.3.3a Emergency Cargo Pump4.4.1a HD Gas Compressor4.4.2a LD Gas Compressor4.5a Boil-Off/Warm-Up Heater4.6a LNG Vaporizer4.7a Forcing Vaporizer4.8.1a Foxboro CTS4.8.1b Computer Cargo Record Sheets

Issue: 1 Front Matter of 8

HEAVY INDUSTRIESShipping Co.,Ltd SK Supreme Cargo System Operating Manual

4.8.2a Whessoe Float Level Gauge4.8.3a Trim/List Indicator4.9a Nitrogen Generator4.10a Inert Gas and Dry Air Generator4.11a Fixed Gas Detection System4.12.1a Cargo and Ballast Valve Control System4.12.2a Emergency Shutdown and Cargo Tank

Protection Scheme4.12.3a Ship Shore Optic Fibre Transmission and

ESD Link System Schematic Link4.12.4a Mooring Load Monitor System4.12.4b Mooring Load Monitor System4.14.1a Cargo Tank / IBS / IS Relief Valves4.14.2b IBS/IS Relief Valve Layout4.15.1a Ballast Piping4.15.2a Ballast Level and Draught Indicating System

Part 5: Cargo Auxiliary and Deck System

5.1 Temperature Monitoring System

5.2 IBS/IS Nitrogen Pressurising and Control System

5.3 Cofferdam Heating System 5.3.1 Glycol Water Heater 5.3.2 Cofferdam Heating including Control 5.3.3 Hull Ventilation

5.4 Ballast Tank Blowing System

5.5 Fire Fighting System 5.5.1 Fire and Wash Deck System 5.5.2 Water Spray System 5.5.3 Dry Powder System 5.5.4 CO2 System 5.5.5 Fire Detection System

5.6 Auxiliary Fresh Water Cooling System

5.7 Deck Scupper and Bilge System

Illustrations5.1a Temperature Monitoring System5.1b Temperature Monitoring System Points in

Cofferdam5.2a Nitrogen Pressurising and Control System5.2b IBS Pressure Control5.2c IS Pressure Control5.3.1a Glycol Water Heater5.3.2a Cofferdam Heating System

5.3.3a Hull Ventilation5.4.a Ballast Tank Blowing System5.5.1a Fire and Wash Deck System5.5.2a Water Spray System5.5.3a Dry Powder System5.5.3b Dry Powder Locations5.5.4a CO2 System 5.5.5a Fire Detection System5.6a Auxiliary Fresh Water Cooling System5.7a Deck Scupper and Bilge System

Part 6: Cargo Operations

6.1 Insulation Space (IBS/IS) Nitrogenation 6.1.1 In-Service Test

6.2 Post Dry Dock Operation6.2.1 Drying Cargo Tanks 6.2.2 Inerting Cargo Tanks 6.2.3 Gassing-Up Cargo Tanks 6.2.4 Cooling Down Cargo Tanks

6.3 Ballast Passage 6.3.1 Cooling Down Cargo Tanks Prior to Arrival6.3.1.1 Spraying During Ballast Voyage, Single Tank

6.4 Loading 6.4.1 Preparations for Loading 6.4.2 Liquid Line Cooldown before Loading 6.4.3 Loading Procedure 6.4.4 Deballasting

6.5 Loaded Voyage With Normal Boil-Off Gas Burning

6.6 Unloading6.6.1 Preparations for Unloading 6.6.2 Liquid Line and Arm Cooldown before

Unloading 6.6.3 Unloading Procedure 6.6.4 Ballasting

6.7 Pre Dry Dock Operations6.7.1 Stripping and Line Draining6.7.2 Warm-Up Cargo Tanks 6.7.3 Gas Freeing 6.7.4 Aerating Cargo Tanks

Illustrations6.1a Insulation Space (IBS/IS) Nitrogenation6.2.1a Drying Cargo Tanks

6.2.2a Inerting Cargo Tanks Prior to Gassing-Up6.2.3a Gassing-Up Cargo Tanks6.2.3b Gassing-Up Cargo Tanks Return to Terminal6.2.4a Cooling Down Cargo Tanks after Gassing-Up6.3.1a Cooling Down Cargo Tanks Prior to Arrival6.3.3.1b Cooling Down Cargo Tanks Prior to Arrival

on Ballast Voyage6.4.2a Liquid Line Cooldown before Loading6.4.3a Loading With Vapour Return to Shore via

HD Compressor6.4.4a Deballasting6.5a Gas Burning on Loaded Voyage6.6.1a Inerting Manifold Connections6.6.2a Liquid Line and Arm Cooldown before

Unloading 6.6.3a Unloading With Gas Return to Shore6.6.4a Ballasting6.7.1a Stripping and Line Draining6.7.2a Tank Warm-up6.7.3a Gas Freeing6.7.4a Aerating Cargo Tanks

Part 7: Emergency Procedures

7.1 LNG Vapour Leakage to Barrier

7.2 LNG Liquid Leakage to Barrier

7.3 Water Leakage to Barrier

7.4 Emergency Cargo Pump Installation

7.5 Fire and Emergency Breakaway

7.6 One Tank Operation7.6.1 Warming-up (No.4 tank)7.6.2 Gas Freeing One Tank7.6.3 Prepare Tank for Aeration

7.7 Ship to Ship Transfer

7.8 LNG Jettison

Illustrations7.3a Water Drain from Insulation Space7.4a Emergency Cargo Pump Fitting Sequence7.6.1a One Tank Warm-up (No.4 tank)7.6.2a One Tank Inerting (No.4)7.6.3a One Tank Aerating (No.4)



Issue and Update ControlThis manual is provided with a system of issue and updatecontrol. Controlling documents ensures that:

• Documents conform to a standard format;

• Amendments are carried out by relevant personnel;

• Each document or update to a document is approvedbefore issue;

• A history of updates is maintained;

• Updates are issued to all registered holders ofdocuments;

• Sections are removed from circulation when obsolete.

Document control is achieved by the use of the footerprovided on every page and the issue and update tablebelow.

In the right hand corner of each footer are details of thepages section number and title followed by the pagenumber of the section. In the left hand corner of eachfooter is the issue number.

Details of each section are given in the first column of theissue and update control table. The table thus forms amatrix into which the dates of issue of the originaldocument and any subsequent updated sections arelocated.

The information and guidance contained herein isproduced for the assistance of certificated officers who byvirtue of such certification are deemed competent tooperate the vessel to which such information and guidancerefers. Any conflict arising between the information andguidance provided herein and the professional judgementof such competent officers must be immediately resolvedby reference to SK Shipping Co., Ltd TechnicalOperations Office.

This manual was produced by:

WORLDWIDE MARINE TECHNOLOGY LTD.

For any new issue or update contact:

The Technical DirectorWMT Technical OfficeThe Court House15 Glynne WayHawardenDeeside, FlintshireCH5 3NS, UK

E-Mail: [email protected]



Issue 1 Issue 2 Issue 3 Issue 4List of Contents January 2001Issues and Updates January 2001List of Symbols January 2001Illustration Colour Scheme January 2001

Text1.1.1 January 20011.1.2 January 20011.1.3 January 20011.1.4 January 20011.2 January 20011.3 January 20011.3.1 January 20011.3.2 January 20011.4 January 2001

Illustrations1.1.3a January 20011.1.3b January 20011.3.2a January 20011.3.2b January 20011.3.2c January 20011.4a January 2001

Text2.1 January 20012.1.1 January 20012.2 January 20012.2.1 January 20012.2.2 January 2001

Illustrations2.1a January 20012.1b January 20012.1c January 20012.1d January 20012.1e January 20012.2.1a January 20012.2.2a January 2001

Text3.1 January 20013.2 January 20013.2.1 January 20013.2.2 January 20013.2.3 January 20013.2.4 January 20013.2.5 January 20013.2.6 January 2001



Issue 1 Issue 2 Issue 3 Issue 43.2.7 January 2001

Illustrations3.2.1a January 20013.2.1b January 20013.2.7a January 2001

Text4.1 January 20014.2 January 20014.2.1 January 20014.2.2 January 20014.2.3 January 20014.2.4 January 20014.2.5 January 20014.2.6 January 20014.2.7 January 20014.3 January 20014.3.1 January 20014.3.2 January 20014.3.3 January 20014.4 January 20014.4.1 January 20014.4.2 January 20014.5 January 20014.6 January 20014.7 January 20014.8 January 20014.9 January 20014.10 January 20014.11 January 20014.12 January 20014.12.1 January 20014.12.2 January 20014.12.3 January 20014.12.4 January 20014.13 January 20014.14 January 20014.14.1 January 20014.14.24.14.3 January 20014.15 January 20014.15.1 January 20014.15.2 January 2001

Illustrations4.2a January 20014.3.1a January 20014.3.1b January 2001

Issue 1 Issue 2 Issue 3 Issue 44.3.2a January 20014.3.2b January 20014.3.2c January 20014.3.3a January 20014.4.1a January 20014.4.2a January 20014.5a January 20014.6a January 20014.7a January 20014.8.1a January 20014.8.1b January 20014.8.2a January 20014.8.3a January 20014.9a January 20014.10a January 20014.11a January 20014.12.1a January 20014.12.2a January 20014.12.3a January 20014.12.4a January 20014.12.4b January 20014.15.1a January 20014.15.2a January 2001

Text5.1 January 20015.2 January 20015.3 January 20015.3.1 January 20015.3.2 January 20015.3.3 January 20015.4 January 20015.5 January 20015.5.1 January 20015.5.2 January 20015.5.3 January 20015.5.4 January 20015.5.5 January 20015.6 January 20015.7 January 20012.15.3 January 20012.5.2 January 2001

Illustrations5.1a January 20015.1b January 20015.2a January 20015.2b January 20015.2c January 2001



Issue 1 Issue 2 Issue 3 Issue 4Illustrations5.3.1a January 20015.3.2a January 20015.3.3a January 20015.4a January 20015.5.1a January 20015.5.2a January 20015.5.3a January 20015.5.3b January 20015.5.4a January 20015.5.5a January 20015.6a January 20015.7a January 2001

Text6.1 January 20016.1.1 January 20016.2 January 20016.2.1 January 20016.2.2 January 20016.2.3 January 20016.2.4 January 20016.3 January 20016.3.1 January 20016.3.1.1 January 20016.4 January 20016.4.1 January 20016.4.2 January 20016.4.3 January 20016.4.4 January 20016.5 January 20016.6 January 20016.6.1 January 20016.6.2 January 20016.6.3 January 20016.6.4 January 20016.7 January 20016.7.1 January 20016.7.2 January 20016.7.3 January 20016.7.4 January 2001

Illustrations6.1a January 20016.2.1a January 20016.2.2a January 20016.2.3a January 20016.2.3b January 20016.2.4a January 2001

Issue 1 Issue 2 Issue 3 Issue 46.3.1a January 20016.3.1.1b January 20016.4.2a January 20016.4.3a January 20016.4.4a January 20016.5a January 20016.6.1a January 20016.6.2a January 20016.6.3a January 20016.6.4a January 20016.7.1a January 20016.7.2a January 20016.7.3a January 20016.7.4a January 2001

Text7.1 January 20017.2 January 20017.3 January 20017.4 January 20017.5 January 20017.6 January 20017.6.1 January 20017.6.2 January 20017.6.3 January 20017.7 January 20017.8 January 2001

Illustrations7.3a January 20017.4a January 20017.6.1a January 20017.6.2a January 20017.6.3a January 2001


Deck Stand (Manual)

Deck Stand (Hydraulic)

Filter Regulating Valvewith Strainer

Surface Valve

Air Horn

Fire Hose Box

Foam Box

Hand Operated

Hydraulic Operated(Open/Shut)

Pneumatic Operated(Open/Shut)

Intermediate Position

Hydraulic Operated ButterflyValve (Throttling Type)

Hydraulic Motor Driven GlobeValve (Throttling Type)

Control

Electric Motor Driven

Air Motor Driven

Solenoid Actuator

Cylinder Piston Actuator

Spring

Centrifugal Type Pump

Rotary (Gear, Screw,Mono) Type Pump

Hand Pump

Reciprocating Type Pump

Diaphragm Pump

Eductor (Ejector)

Suction Bell Mouth

Discharge/Drain

Simplex Strainer

Duplex Strainer withChangeover Cock

Y-Type Strainer

Rose Box

Mud Box

Drain and Water Separator

Air or Gas Trap

Hopper without Cover

Vent Pipe

Vent Pipe withFlame Screen

Steam Trap with Strainerand Drain Cock

Sounding Head withFilling Cap

Flow Meter

Observation Glass

Not ConnectedCrossing Pipe

Connected Crossing Pipe

Pilot Operated Safety Valve

Compressor

Conical Strainer

Sprayers

Locked OpenL.O

Locked ClosedL.C

T Pipe

Blind (Blank) Flange

Orifice

Flexible Hose Joint

Spool Piece

Emergency Shutdown System

Stop Valve

Mechanical Symbols and Colour Scheme for Cargo System

Gate Valve

Butterfly Valve

Screw Down Non-ReturnValve

Lift Check Non-ReturnValve

Self-Closing Valve

Pressure Regulating Valve

Safety / Relief Valve

Manual Regulating Valve

Swing Check Valve

Three-Way Valve

Hose Valve

Pressure Reducing Valve

Two-Way Cock (S-Type)

Three-Way Cock(L-Type / T-Type)

M

F

A

Thermostatic Temperature

Orifice (Flow Meter)

Regulating Valve

F B

H B

Spectacle Flange( Open, Shut)

P2P1

Steam

Condensate

LNG Liquid Line

LNG Stripping Line

LNG Spray Line

LNG Vaporizer Supply

Forcing Vaporizer Supply

LNG Drain Line

LNG Vapour Line

Pressure, Relief Line

Fuel Gas Line

Emergency Vent

Glycol Water

Ballast Water

Sea Water

Insulation Space Nitrogen

Liquid Nitrogen

Gaseous Nitrogen

Inter-Barrier Space Nitrogen

Inert Gas

FW Cooling HT and LT

Domestic FW Hot and Cold

Lubricating Oil

Compressed Air

Bilge Water

Diesel Oil

Fire Water

CO2 Smothering

Electric Signal

H

ESD

Cargo Valve Numbering

1st Group

1st Group: Process Fluid

CL Liquid Line

CS Spray/Stripping Line

CG Vapour and Gas Line

CN Nitrogen Line

CR Cargo Relief Valve

SA Sampling Pipe for Cargo Tank

FL Float Type Tank Level Gauge Pipe

FM Flow Meter

2nd Group: Location

0 Cargo/Vapour Manifold

1 No.1 Cargo Tank

2 No.2 Cargo Tank

3 No.3 Cargo Tank

4 No.4 Cargo Tank

7 Main Line

8 Cargo Machinery Room Outside

9 Cargo Machinery Room Inside

3rd Group: Serial Number

3rd Group2nd Group



Resistor

Group junction box xx(xx = location)

Whistle relay box

I/O Cabinet (alarmmonitoring system)

Governor motor

Alarm monitoringsystem

Water transducer

Humidistat

WT joint box2 glands (4 glands)

NWT joint box

Receptacle

Voltage referenceselector

Solenoid valve

Variable resistor

Dimmer

Diode

Capacitor

Fuse

Snap switch

Changeover switch(cam switch)

Indicator lampwith transformer

Indicator lamp

Relay coil

Buzzer

Bell

110 Central meter

Rectifier equipment

Making contact

Making contact

Making contact

Breaking

Breaking

Breaking

Making contact

Breaking

Pushbutton switch(alternative)

Pushbutton switch(alternative)

Power supply unit

Zener barrier box

Limit switch

GSP

CP

PD

LD

LD

L

M

Starter (direct on line)

Local groupstarter panel

Control panel

440V dist. board

230V power dist. board

Lighting dist. board

Air circuit breaker

MCCB 1 phase

MCCB 3 phase

Disconnection switch

Battery charger

Battery

Pushbutton (start/stop)

Pushbutton(start/stop/running)

Emergency stoppushbutton box

Fuse

Overcurrent relay

Diesel generator

Liquid sensor

Transformer

J

HS

VR

( )J J

Current to pressconverter

Press to currentconverter

RPM pick-up

Gauge

Intrinsically safetycircuit

10A

RL

D-D

BZ

BL

XXXXXXX

Z B K

LM

IS

PI

IP

AC induction motorM

L D

Emergency generatorEG

DG

WT

AMS

GM

IO

S I GR B

GJB/XX

Locally MountedInstrument

Remotely MountedInstrument

DPI Differential Pressure IndicationDPS Differential Pressure SwitchDTA Deviation Temperature AlarmDI Dew PointESA Emergency Stop AlarmFA Flow AlarmFC Flow ControlFFA Flame Failure AlarmFI Flow IndicationFS Flow SwitchLA Level AlarmLC Level ControlLI Level IndicationLIA Level Alarm/IndicationLS Level SwitchPA Pressure AlarmPC Pressure ControlPI Pressure IndicationPIA Pressure Alarm/IndicationPS Pressure SwitchPSH Pressure Shut DownPSL Pressure Slow DownOI Oxygen IndicatorRPM RPM IndicationSA Salinity AlarmSI Salinity IndicationSM Smoke IndicatorTA Temperature AlarmTC Temperature ControlTI Temperature IndicationTIA Temperature Alarm/IndicationTS Temperature SwitchXA Relay ContactZS Valve Open/Closed Indication

Space heater(element type)

R P M

Earth

Shield wire

With timelimit inclosing

With timelimit inopening

Flickerrelay

XXX

Auxiliaryrelaycontact

Trip Automatic trip

Symbol Description

Density (Oil)

Differential Pressure

Deviation Temperature

Flow

Level

Pressure

Salinity

Temperature

Viscosity

General Failure

Limit (or Position)

Alarm

Control

Indication

Switch

Transmitter

Recording

Shut-Down

Slow-Down

Indication and Alarm

High

Low

1st L

ette

r2n

d/3r

d Le

tter

3rd/

4th

Lette

r

D

DP

DT

F

L

P

S

T

V

X

Z

A

C

I

S

T

R

SH

SL

IA

H

L

Electrical Symbols and Abbreviations


Introduction

GeneralAlthough the ship is supplied with shipbuilder’s plans and manufacturer’sinstruction books, there is no single handbook which gives guidance onoperating complete systems, as distinct from individual items of machinery.

The purpose of this manual is to fill some of the gaps and to provide the ship’sofficers with additional information not otherwise available on board. It isintended to be used in conjunction with the other plans and instruction booksalready on board and in no way replaces or supersedes them.

In addition to containing detailed information of the cargo and related systems,the CARGO OPERATING MANUAL contains safety procedures, andprocedures to be observed in emergencies and after accidents. Used inconjunction with the SK Shipping Co., Ltd SMS MANUAL, this informationis designed to ensure the safety and efficient operation of the ships. Quickreference to the relevant information is assisted by division of the manual intoParts and Sections, detailed in the general list of contents on the precedingpages.

Reference is made in this book to appropriate plans or instruction books.For other information refer to:

1) Books and Publications contained in the SMS Directory

2) SMS MANUAL

In many cases the best operating practice can only be learned by experience.Where the information in this manual is found to be inadequate or incorrect,details should be sent to the SK Shipping Co., Ltd LNG Operations Office sothat revisions may be made to manuals of other ships of the same class.

Safe OperationThe safety of the ship depends on the care and attention of all on board. Mostsafety precautions are a matter of common sense and good housekeeping andare detailed in the various manuals available on board. However, records showthat even experienced operators sometimes neglect safety precautions throughover-familiarity and the following basic rules must be remembered at all times.

1 Never continue to operate any machine or equipment whichappears to be potentially unsafe or dangerous and always reportsuch a condition immediately.

2 Make a point of testing all safety equipment and devicesregularly. Always test safety trips before starting any equipment.In particular, overspeed trips on auxiliary turbines must be testedbefore putting the unit into operation.

3 Never ignore any unusual or suspicious circumstances, no matterhow trivial. Small symptoms often appear before a major failureoccurs.

4 Never underestimate the fire hazard of petroleum products,whether fuel oil or cargo vapour.

5 Never start a machine remotely from the control room withoutchecking visually if the machine is able to operate satisfactorily.

In the design of equipment and machinery, devices are included to ensure that,as far as possible, in the event of a fault occurring, whether on the part of theequipment or the operator, the equipment concerned will cease to functionwithout danger to personnel or damage to the machine. If these safety devicesare neglected, the operation of any machine is potentially dangerous.

DescriptionThe concept of this Cargo Operating Manual is based on the presentation ofoperating procedures in the form of one general sequential chart (algorithm)which gives a step-by-step procedure for performing operations required forthe carriage of LNG.

The manual consists of introductory sections which describe the systems andequipment fitted and their method of operation related to a schematic diagramwhere applicable. This is then followed where required by detailed operatingprocedures for the system or equipment involved.

The overview of cargo operations, as detailed in Section 4.1, consists of a basicoperating algorithm which sets out the procedure for cargo handling operationsfrom drydock to first loading and from first loading through the normal cargooperating cycle. The relevant illustration and operation Section number islocated on the right hand side of each box.

Each cargo handling operation consists of a detailed introductory sectionwhich describes the objectives and methods of performing the operationrelated to the appropriate flow sheet which shows pipelines in use anddirections of flow within the pipelines.

Details of valves which are OPEN during the different operations are providedin-text for reference.

The ‘valves’ and ‘fittings’ identifications used in this manual are the same asthose used by SK Shipping Co., Ltd.

IllustrationsAll illustrations are referred to in the text and are located either in-text wheresufficiently small or above the text, so that both the text and illustration areaccessible when the manual is laid open. When text concerning an illustrationcovers several pages the illustration is duplicated above each page of text.

Where flows are detailed in an illustration these are shown in colour. A key ofall colours and line styles used in an illustration is provided on the illustration.Details of colour coding used in the illustrations are given in the colourscheme.

Symbols given in the manual adhere to international standards and keys to thesymbols used throughout the manual are given on the following pages.

NoticesThe following notices occur throughout this manual:

! WarningWarnings are given to draw reader’s attention to operation whereDANGER TO LIFE OR LIMB MAY OCCUR.

! CautionCautions are given to draw reader’s attention to operations where DAMAGETO EQUIPMENT MAY OCCUR.

(Note !)Notes are given to draw reader’s attention to points of interest or to supply sup-plementary information.



Part 1Design Concept of the Vessel

1.1 Principal Particulars

1.1.1 Principal Particulars of the Ship

Shipbuilder Samsung Heavy IndustriesKoje ShipyardKorea

Ship Number 1207Ship Name SK SupremeYear Built 1998Delivered January 2000Nationality KoreanPort of Registration PanamaRadio Call Sign 3FOB9IMO No. 9157739Type of Cargo LNGType of Ship Segregated Ballast LNG CarrierStem Bulbous Bow and Raked StemStern TransomNavigation Foreign GoingClassification KR and ABS

+A1 (E), Liquefied Natural GasCarrier, Ship Type 2G, +AMS,+ACCU, OMBO, UWILD,PMS including CM

Length (Overall) 278.852mLength (Between Perpendiculars) 266.000mBreadth Moulded 42.600mDepth Moulded 26.000mDesign Draught 11.300mScantling Draught Moulded 12.000m

Capacity 138,545m3 at specific gravity 461.1kg/m3

Maximum Speed - Trials 21.66 knotsService Speed - at 11.3m Draught 20.7 knots

Manning Design Complement 25 Officers15 Crew

Steering Gear

Maker Samsung HatlapaKorea

Type Teleram R4ST 7002- Ram, 4 Cylinder Rapson Slide, Hydraulic

Isolation System SafematicSystem Capacity 1,300 litresDia of Rudderstock 600mm(tiller)Working Pressure 192 barRudder Angle Speed 65° in 28 secondsRudder Angle Limit Switch 45.6°Rudder Angle Mechanical Stops 47°

Main PumpType A2P 355 HDDelivery 350 litre/minute

Main MotorOutput 107 kW at 1,160 rpmCapacity 440V, 3 phase, 60Hz

Issue: 1 1.1 Principal Particulars Page 1 of 7




1.1.2 Principal Particulars of Cargo Machinery

Main Cargo PumpsType: Ebara 12EC-24Capacity: Rated at 1,700m3/h at 145m headMotor Rating: 465.1kWMotor Speed: 1,780 rpmStarting Method: Direct on lineNumber of Stages: 1No. of sets: 8 (2 per cargo tank)

Spray/Stripping PumpsType: Ebara 2EC-092Capacity: Rated at 50m3/h at 145m headMotor Rating: 22.4kWMotor Speed: 3,600 rpmStarting Time: 1.2 secondsNumber of Stages: 2No. of sets: 4 (1 per cargo tank)

Emergency Cargo PumpsType: Ebara 8ECR-12Capacity: Rated at 550m3/h at 155m headMotor Rating: 171kWMotor Speed: 3,560 rpmStarting Method: Direct on lineNumber of Stages: 1No. of sets: 1 (Located in Deck Store, or in a Tank)

HD CompressorType: Atlas Copco ACE GT 050 T1K1Capacity: 48,751kg/hSuction Volume: 32,000m3/hSuction Temperature: -140°CSuction Pressure: 1.03bar abs.Discharge Pressure: 2.0bar abs.Discharge Temperature: Approx -109°CCompressor Rotor Speed: 11,531 rpmMotor Speed: 3.560 rpmMotor Power: 950kWNo. of sets: 2

LD CompressorType: Atlas Copco ACE GT 026 T1K1Capacity: 12,949kg/hSuction Volume: 8,500m3/hSuction Temperature: -40°CSuction Pressure: 1.03bar abs.Discharge Pressure: 2.0bar abs.Discharge Temperature: Approx +13°CCompressor Rotor Speed: 13,997 ~ 27,994 rpmMotor Speed: 1,780 ~ 3,560 rpmMotor Power: 430kWNo. of sets: 2

LNG VaporizerType: Cryostar 65-UT-38/34-5.9Capacity: 21,300kg/h (47m3/h inlet volume flow)Heating: Steam at 8kg/cm2

No. of sets: 1

Forcing VaporizerType: Cryostar 34-UT-25/21-3.6Capacity: 7,000kg/h (16m3/h inlet volume flow)Heating: Steam at 8kg/cm2

No. of sets: 1

Mist SeparatorType: Cryostar VMS-10/12-1000Output Range: 2,160 ~ 8,630m3/hNo. of sets: 1

Boil-Off/Warm-Up HeatersType: Cryostar 65-UT-38/34-3.2Capacity: 16,000kg/h (10.1m3/h inlet volume flow)Heating: Steam at 8kg/cm2

No. of sets: 2

Glycol Heaters (Steam)Type: Beu 273 - 1800Capacity: 18,000kg/h glycolHeating: Steam at 8kg/cm2

No. of sets: 2(Electric) Cetal

Type: TB80-20ERating: 80 kWNo. of sets: 1

Glycol Water PumpType: Shinko SVP 65MCapacity: Rated at 30m3/h at 30m w.g.No. of sets: 2

Nitrogen GeneratorType: Prism Nitrogen SystemCapacity: 2 x 90Nm3/h at 97%N2

Inert Gas / Dry Air GeneratorType: Kaverner MossCapacity:Inert Gas 14,000Nm3/hDry Air 14,000Nm3/hNo. of sets: 1

Tank Safety ValveCargo TankType: Expon 10” x 12”Capacity: 23,971Nm3/hSet Pressure: 25kPaNo. of sets: 8 plus 1 spare

Primary IBSType: R1101 2”Capacity: 289Nm3/hSet Pressure: 3kPaNo. of sets: 8 plus 1 spare

Secondary ISType: R1101 2”Capacity: 318Nm3/hSet Pressure: 3.5kPaNo. of sets: 8 plus 1 spare

Ballast Tank Blowing SystemType: Hybon Screw CompressorCapacity: 1,215m3/hNo. of sets: 1

Ballast PumpType: ShinkoModel: GVD500-2MCapacity: 3,000m3/h at 35mthNo. of sets: 3

Ballast Stripping EductorType: Kiwon Industrial Co.Capacity: 300m3/hNo. of sets: 2Driving pressure: 12kg/cm2


NO SMOKING

Principal Dimensions

Length (Overall) 278.852m

Length (Between Perpendiculars) 266.000m

Breadth (Moulded) 42.600m

Depth (Moulded) 26.000m

Designed Draught (Moulded) 11.300m

Scantling Draught (Moulded) 12.000m

1.1.3a General Arrangement



CargoOffice

C.A.C.CEl. Equipt.RoomConference

Room

D Deck C Deck

ShipsOffice

El. CableSpace

El. CableSpace

SafetyLocker

E Deck F Deck

LiftLift

El. CableSpace Wheelhouse

& Chart Space

Navigation/BridgeDeck

Wheelhouse Top

CO2 BottleRoom

EmergencyGenerator Room

Hospital

A DeckB Deck

E.S.C.R.

No.1 MSBRoom

No.2 MSBRoom

E.R. 2nd DeckE.R. 3rd DeckE.R. 4th DeckE.R. Floor Deck Bosun's Store

1.1.3b General Arrangement Accommodation and Engine Room Areas




LNG Cargo Tanks at -163°C

CompartmentLocationFrame

Number Volume100% Full m3

Volume98% Full m3

L.C.G. FromMid (Mld)

V.C.G. AboveB.L (Mld)

Capacities Max. M.T.of

Inertia m4

122-135

105-121

88-104

72-87

24567

39454

39454

35070

76.524

35.554

-40.521

-54.216

17.614

16.535

16.535

16.538

Total 138545

100% Full

106907

186760

186760

166009

No.1 Cargo Tank

No.2 Cargo Tank

No.3 Cargo Tank

No.4 Cargo Tank

Water Ballast Tanks



Weight 100%Full Tonnes

L.C.G. FromMid

V.C.G. AboveB.L


Inertia m4

172-192

136-164

136-164

121-136

121-136

104-121

104-121

87-104

87-104

71-87

71-87-6-16

917.4

3122.2

3121.7

5947.5

5947.5

5762.9

5762.9

5797.0

5797.0

4986.8

4986.82059.1

940.3

3200.3

3199.8

6096.2

6096.2

5906.9

5906.9

5942.0

5942.0

5111.5

5111.52110.6

129.470

105.661

105.663

73.212

73.212

34.128

34.128

-11.844

-11.844

-54.976

-54.976-128.965

12.263

11.588

11.588

10.334

10.334

8.556

8.556

8.519

8.519

8.810

8.81015.326

Total 54208.8 55426.8

100% Full

779

2341

2341

10717

10717

23932

23932

24375

24375

19829

1982920570

Fore Peak Tank Centre

Forward WB Tank Port

Forward WB Tank Stb’d

No.1 WB Tank Port

No.1 WB Tank Stb’d

No.2 WB Tank Port


No.3 WB Tank Port


No.4 WB Tank Port

No.4 WB Tank Stb’dAft Peak Tank

S.G. = 1.025

1.1.4 Tanks and Capacity Plan


1.1 Principal Particulars Page 6 of 7

Lubrication Oil Tanks



Volume98% Full m3





Inertia m4

26-36

49-51

49-51

47-49

49-51

65-68

62-651

55-62

41-47

77.1

6.0

6.0

20.0

8.0

33.9

33.9

79.2

39.5

75.6

5.9

5.9

19.6

7.9

33.2

33.2

77.6

38.8

68.0

5.3

5.3

17.7

7.1

29.9

29.9

69.8

34.9

-108.114

-93.000

-93.000

-94.600

-93.000

-79.800

-82.200

-86.200

-97.800

Total

Total

303.6 297.7 267.9

6690.7 6356.3 6292.8

Total 594.6 564.9 508.4

100% Full

2.517

22.690

22.690

22.690

22.690

17.080

17.080

17.080

22.840

Main Engine LO Sump (C)

Gen. Turbine LO Stor. Tk (S)

Gen. Turbine LO Sett. Tk. (S)

Gen. Engine LO Stor. Tk. (S)

Gen. Engine LO Sett. Tk. (S)

No.1 Main LO Stor. Tk (S)

No.2 Main LO Stor. Tk (S)

Main LO Settling Tk (S)

Main LO Gravity Tk (S)

S.G. = 0.900

79

0

0

9

1

14

14

32

6

Heavy Fuel Oil



Volume95% Full m3





Inertia m4

140-164

35-71

35-71

51-62

51-62

2604.7

1894.1

1617.7

287.1

287.1

2474.4

1799.4

1536.9

272.8

272.8

2449.7

1781.4

1521.5

270.1

270.1

-106.679

-88.363

-86.780

-87.776

-87.776

100% Full

14.900

15.599

16.195

20.735

20.735

Forward HFO Stor Tank (C)

HFO Storage Tank (Port)

HFO Storage Tank (Stb’d)

HFO Settling Tank (Port)

HFO Settling Tank (Stb’d)

S.G. = 0.990

1729

231

190

26

26

Diesel Oil Tanks



Volume95% Full m3





Inertia m4

35-47

35-43

47-50

418.2

138.2

38.2

397.3

131.3

36.3

357.5

118.2

32.7

-99.890

-101.733

-94.200

100% Full

15.964

23.597

23.603

DO Storage Tank (C)

Light DO Storage Tank (Port)

DO Service Tank (Std’d)

S.G. = 0.900

76

48

7

Issue: Draft 1




S.G. = 1.000

Miscellaneous Tanks


Number Volume 100% Full m3 L.C.G. FromMid (Mld)



Inertia m4

61-71

61-64

46-51

43-46

20-22

62-71

55-62

55-62

59-62

10-16

65-6865-6837-3937-3916-19

112.2

13.1

4.9

2.9

3.6

170.0

35.1

92.2

11.4

60.4

4.34.32.32.39.2

-79.143

-82.990

-94.200

-97.400

-116.165

-79.326

-86.200

-86.046

-84.600

-121.953

-79.666

-79.666-102.565-102.565-118.971

1.585

1.267

9.141

9.141

3.022

1.480

1.200

1.389

6.120

4.146

1.9771.9772.0272.0273.095

Total

Total

528.2

1028.7 1028.7

100% Full

352

3

1

1

1

909

9

403

3

15

551113

HFO Overflow Tank (S)

HFO Drain Tank (S)

LO Sludge Tank (S)

DO Sludge Tank (S)

Stern Tube LO Drain Tank

Bilge Holding Tank (P)

Sep Bilge Holding Tank (P)

Clean Drain Tank (P)

Bilge Primary Tank (P)

Cooling Water Tank (C)

Bilge Water ER Fore (P)Bilge Water ER Fore (S)Bilge Water ER Mid (P)Bilge Water ER Mid (S)Bilge Water ER Aft (C)

Fresh Water Tanks






Inertia m4

9-20

9-20

7-16

7-16

250.5

250.5

262.7

265.0

250.5

250.5

262.7

265.0

-120.734

-120.734

-124.151

-124.121

18.410

18.410

18.236

18.213

100% Full

168

168

264

261

Distilled Water Tank (P)

Distilled Water Tank (S)

Fresh Water Tank (P)

Drinking Water Tank (S)

1.2 Rules and Regulations

Since the introduction of liquefied gas carriers into the shipping field, it wasrecognised that there was a need for an International code for the carriage ofliquefied gases in bulk.

At the beginning of the 1970’s The Marine Safety Committee (MSC) of theInternational Maritime Organisation (IMO) known then as the InternationalConsultative Maritime Organisation (IMCO) started work on a Gas CarrierCode with the participation of the major country delegations representing GasCarrier owners, the International Association of Classification Societies, theUnited States Coast Guard and several other International associations.

The result of this work was the “Code for the Construction and Equipment ofships Carrying Liquefied Gases in Bulk” introduced under AssemblyResolution A328 (IX) in November 1975.

This was the first code developed by IMO having direct applicability to GasCarriers.

The intention was to provide “a standard for the safe bulk carriage of liquefiedgases (and certain other substances) by sea by prescribing design and con-structional features of ships and their equipment, so as to minimise risks toships, their crew and the environment”.

The GC Code has been adopted by most countries interested by the transportof liquefied gases by sea as well as all Classification Societies and is now partof SOLAS.

The USCG have added some extra requirements to the GC Code for shipstrading in the USA waters.

The applicability of the code is as follows :

Gas Carriers built after June 1986 (the IGC Code)The Code which applies to new gas carriers (built after June 1986) is the“International Code for the Construction and Equipment of Ships carryingLiquefied Gases in Bulk” known as the IGC code.

At a meeting of the MSC in 1983 approving the second set of amendments toSOLAS the requirements of the IGC Code become mandatory with almostimmediate effect.

Gas Carriers built between 1976 and 1986 (the GC Code)The regulations covering gas carriers built after 1976 but before 1st July 1986is the “Code for the Construction and Equipment of Ships Carrying LiquefiedGases in Bulk” known as the Gas Carrier Code or GC Code and adopted underAssembly resolution A328 (IX).

Since 1975 the MSC has approved four sets of amendments to the GC Code,the latest in June 1993.

Gas Carriers built before 1977 (the Existing Ship Code)

The regulations covering gas carriers built before 1977 are contained in the“Code for Existing Ships Carrying Liquefied Gases in Bulk” first advertisedunder Assembly Resolution A 329 (IX). Its content is similar to the GC code,though less extensive.

The Existing Ship Code was completed in 1976 and remains as an IMORecommendation for all gas carriers in this fleet of ships.

The IGC Code requires that a Certificate (International Certificate of Fitnessfor the Carriage of Liquefied Gases in Bulk) must be issued to all new gascarriers. The certificate should comply to a pro-forma, as set out in “ModelForm” attached as an Appendix to the Code and should be available on boardall new gas carriers.

The basic philosophy behind the code is summarised in the International Codefor the Construction and Equipment of ships Carrying Liquefied Gases in Bulkwhich is readily available on board in the ship’s library.

PreambleMost of the provisions in the IMO Code are covered by the ClassificationSociety’s rules and regulations, however attention must be drawn to the factthat it contains requirements that are not within the scope of classification asdefined in the Society’s rules. For example, Chapter II Ship SurvivalCapability, Chapter XIV Personnel Protection and Chapter XVII OperatingRequirements.

However, where the Societies are authorised to issue the InternationalCertificate of fitness, these requirements, together with any amendments orinterpretations adopted by the appropriate National Authority, will be appliedwhere applicable.

Since the IMO recommendations defer some matters to the discretion of eachadministration, and in other matters are not specific enough for Coast Guardregulatory purpose, several major changes have been introduced from the codein the proposed Coast Guard rules. These changes are discussed in thefollowing paragraphs.

“Liquefied gas” is changed from the Code’s definition of “a product having avapour pressure of 2.8 kp/cm2 at 37.8°C” to the proposed definition of “aproduct having a vapour pressure of 1.76 kp/cm2 at 37.8°C”. This is a changein the definition from a Reid vapour pressure of 40 psia to 25 psia. The changein the Reid vapour pressure includes the “certain other substances” referred toin paragraph 1.2 of the Code, but does not include any product in IMO’s

Chemical Code except ethylene, which is presently listed in the Code and theChemical Code. The change in the Reid vapour pressure was proposed by theU.S. delegation to IMO but the change was not adopted, although there wasapparently no objection to it. The change, however, does not effect the list ofregulated cargoes.

The rate of air change between the air lock door is not specified in the Code(paragraph 3.6.1) but is proposed at 12 changes per hour.

It is proposed that leaked cargo from interbarrier spaces be pumped to anemergency dump. It is proposed as an alternative to the Code requirement thatleaked cargo be returned to the cargo tanks.

Chapter 4 of the Code includes a provision for the evaluation of the insulationand hull steel assuming, for the purpose of design calculations, that the cargotank and secondary barrier, if installed, are at the design temperature and theambient outside air and sea design temperatures as follows :

General Worldwide

Still Air : +5°C (41°F)Sea Water : 0°C (32°F)

Chapter 4 also provides that each administration may set higher or lowerambient design temperatures. This document proposed the following tempera-tures :

Any Waters in the World, except Alaskan Waters

Air (at 5 knots) : -18°C (0°F)Still Sea Water : 0°C (32°F)

Alaskan Waters

Air (at 5 knots) : -29°C (–20°F)Still Sea Water : - 2°C (28°F)

Issue: 1 1.2 Rules and Regulations Page 1 of 2


The proposed regulations specify enhanced grades of steel for crack arrestingpurposes in the deck stringer, sheer strake, and bilge strake. The minimumacceptable grade for the deck stringer and the sheer strake is Grade E or anequivalent steel that is specially approved by the Commandant (G-MMT). Theminimum acceptable grades for the bilge strake are Grade D or Grade E or anequivalent steel that is specially approved by the Commandant (G-MMT).

The proposed allowable stresses for membrane, semi-membrane, andindependent tank type A are the same as the allowable stresses for these tanksin the Code. However, for independent tank types B and C, stress factors arenot the same as the stress factor for these tanks in the Code.

In the Code, the stress factors listed for independent tank types B and C are theminimum factors that may be used in calculation. The stress factors proposedin these regulations meet Section VIII of the ASME Code, 1974, and aregreater than the minimum listed in the Code, and must be used in independenttank type B and C calculations for vessels to which the regulations apply.

The Code allows pressure and temperature control of cargoes by venting cargovapours to the atmosphere when the vessel is at sea and in port if accepted byreceiving administration. It is proposed to prohibit normal venting of cargointo the atmosphere in many ports.

The Code requires the cargo system to be designed to withstand the full vapourpressure of the cargo under conditions of the upper ambient design temperatureor have other means to maintain the cargo tank pressure below the maximumallowable relief valve setting (MARVS) of the tank. These regulations proposethat when the cargo carried is a liquefied gas, the cargo tank pressure must bemaintained below the design vapour pressure indefinitely, the pressure on theLNG tank would be maintained below the design pressure for a period of notless than 21 days. Cargo tank pressure may be maintained below the designpressure by several methods including refrigeration systems, burning boil-offin waste heat or catalytic furnaces, using boil-off as fuel, or a combination ofthese methods. Using the boil-off as a fuel for propulsion is limited to a vesselcarrying LNG.

(Note ! LPG boil-off is not allowed as fuel for propulsion as LPG vapours areheavier than air.)

The proposed regulations also include the following:

1) Transfer requirements for vinyl chloride;

2) Loading requirements for methyl acetylene propadiene mixture;

3) Additional operating requirements;

4) Requirements for inspection or re-inspection of US flag vessels atintervals that are the same as for vessels inspected underSubchapter D. Inspection for certification would be requiredevery 2 years and re-inspection would be required between the10th and 14th month following issuance of a Certificate ofInspection;

5) Requirements for the initial and periodic inspections and tests ofthe cargo containment system, cargo and process piping, and hullheating and cold spots.

The proposed Coast Guard regulations and the Classification Society’s ruleshave cross references showing the corresponding IMO code numbers to allowidentification of the required paragraph.

Issue: 1 1.2 Rules and Regulations Page 2 of 2


Issue: 1 1.3 Design Concept of the Cargo System Page 1 of 4

Illustration 1.3.2a Membrane Cargo Containment (GTT Mark III)

Level WedgeCylindrical Plug

Flat Joint

Primary Barrier(AISI304L Stainless Steal)

Glass Wool

PUF Packing

Plywood

Secondary Barrier (Triplex Scab)

Plywood



Level WedgeCylindrical Plug

Flat Joint

Glass Wool

PUF Packing

Plywood

Secondary Barrie(Triplex Scab)

Plywood

Flat Panel

Flat Panel

Flat Panel

Flat Panel

Illustration 1.3.2b IBS IS Section of Transverse Corner



Fitting ComponentsFor Flat Panel

Cylindrical Plug

Stud

Level Wedge

Nut HM 10

Washer LL 10

Anchoring Strip

Flat Joint

Secondary Barrier(Triplex Scab)

Top Bridge Pad

Cylindrical Plug

Flat Panel

Illustration 1.3.2c IBS IS Flat Panel Junction


1.3 Design Concept of the Cargo System

1.3.1 Design Concept of the Cargo System

The cargo containment system consists of four insulated cargo tanks, separatedfrom each other by transverse cofferdams, and from the outer hull of the vesselby wing and double bottom ballast tanks.

The containment system serves two purposes:

To contain LNG cargo at cryogenic temperature (-160°C).

To insulate the cargo from the hull structure.

The materials used for the hull structure are designed to withstand varyingdegrees of low temperature. At temperatures below their specified limits, thesesteels will crystallise and embrittle. The materials used for the containmentsystem are required to reduce the heat transfer from the hull structure tominimise the boil-off gas from the cargo, as well as to protect the hull structurefrom the effects of cryogenic temperature.

The inner hull is lined with the GTT Mark III integrated tank system,consisting of a thin and flexible membrane, called the primary barrier, whichbears against a supporting insulation structure embodying a secondary barrier.This construction ensures that the entire cargo hydrostatic load is transmittedthrough the membrane and insulation to the hull plating of the vessel.

1.3.2 Membrane Cargo Containment See illustrations 1.3.2a, b, c

Membrane or Primary BarrierThe membrane is an assembly of corrugated sheets 1.2 mm thick, made ofAISI304L stainless steel. The sheets, lap-welded together, have two sets oforthogonal corrugations of ogival shape, where the nominal pitch is equal to340mm by 340mm. The corrugations cross each other by means of geometricalsurfaces which are termed knots.

So that the elongation of the sheets in the two directions of the corrugationswill be the same for the same applied load, it is necessary to give differentdimensions to the corrugations of the two sets. Consequently there is one setof large corrugations, parallel to each other, and one set of small corrugations,also parallel to each other but at right-angles to the first set. Each sheet isformed on an automatic folding machine using special tools.

On each of the tank walls, the corrugations present a pattern of squares, witheach set of corrugations being parallel to one of the axes of the vessel.

Along the edges of the tank the joining of the corrugations on two adjacentwalls takes place by means of angle pieces, each one formed by foldingcorrugation into a specially designed knot.

The sheets are fixed to the supporting insulation along half their perimeter bywelding onto small stainless steel blocks solidly fixed in the insulationstructure. This anchoring has three purposes; it takes up the unbalanced forcesset up by non-uniform or transient temperature conditions, it supports theweight of the sheets on the vertical walls and roof of the tank and it allows asmall vacuum in the tank. The half perimeter is overlapped by, and lap-weldedto, the adjacent sheet. Along the edges and corners of the tank, the sheets areanchored to rigid stainless steel corner pieces, and the corners in turn aresecured onto the insulation by hardwood keys.

The welding process is Tungsten Inert Gas (TIG) without filler metal.

Insulation and Secondary BarrierThe insulation and secondary barrier assembly is composed of the followingelements, as shown in illustration 1.3.2a

Level wedges, fixed to the inner hull and forming a rectangular pattern, serveas a support for the insulation panels bonded to them. The plywood panels ofthe insulation barrier are secured to the inner hull by studs. The level wedgethickness is individually calculated to take into account any slight irregulari-ties in the inner hull surface.

Insulating sandwich panels, composed of an outer plywood face, onto which isbonded the membrane sheets and two layers of insulating foam, form the actualinterbarrier and insulation space barrier. Between the IBS and IS foam layersthere is a triplex membrane (scab) bonded onto the IS foam and forms theimpervious barrier to the nitrogen circulation.

The insulating sandwich panels are assembled by bonding with polyurethaneor epoxy glue. Insulation continuity between the panels is assured byglasswool (flat joint) which are sandwiched between PVC films. Tightness andcontinuity of the secondary barrier is achieved by means of a bonded scab-splice made of prefabricated rigid polyurethane foam with reinforcing glassfibres.

For the corners of the tank, the sandwich panels are cut and assembled to formdihedral and trihedral corners, the joints between the panels of these cornersbeing formed of pre-compressed expanded PVC.

The insulation dimensions have been determined to ensure that: the heat flowinto the tank is limited to such an extent that the evaporation, or boil-off rate,is about 0.15% per day.

The inner hull steel does not attain a temperature below its minimum designvalue, even in the case of failure of the primary barrier. Any deflectionsresulting from applied strains and stresses are acceptable by the primarybarrier.

In addition to these requirements, the insulation acts as a barrier to prevent anycontact between ballast water and the primary barrier, in the event of leakagethrough the inner hull.

The insulation system is designed to maintain the boil-off losses from the cargoat an acceptable level, and to protect the inner hull steel from the effect ofexcessively low temperatures. If the insulation efficiency should deteriorate forany reason, the effect may be a lowering of the inner hull steel temperature, iea cold spot and an increase in boil-off from the affected tank. Increased boil-off is of no direct consequence to the safety of the vessel as any excess gas maybe vented to atmosphere via the forward riser at No.1 tank. The inner hull steeltemperature must, however, be maintained within acceptable limits to preventpossible brittle fracture.

Thermocouples are distributed over the surface of the inner hull, but unless acold spot occurs immediately adjacent to a sensor, these can only serve as ageneral indication of steel temperature. To date, the only sure way of detectingcold spots is by frequent visual inspection of the ballast spaces on the loadedvoyage. (see Section 5.1)

The grade of steel required for the inner hull of the vessel is governed by theminimum temperature this steel will reach at minimum ambient temperature,and assuming the primary barrier, the stainless steel membrane, has failed, sothat the LNG is in contact with the secondary barrier.

In addition to failure of the membrane, local cold spots can occur due to failureof the insulation.

While the inner hull steel quality has been chosen to withstand the minimumtemperature likely to occur in service, prolonged operation at steel tempera-tures below 0°C will cause ice build-up on the plating, which in turn will causea further lowering of steel temperature due to the insulating effect of the ice.To avoid this, glycol heating coils are fitted in each cofferdam space, ofsufficient capacity to maintain the inner hull steel temperature at 5°C under theworst conditions.

If a cold spot is detected either by the inner hull temperature measurementsystem or by visual inspection, the extent and location of the ice formationshould be recorded. Small local cold spots are not critical, and provided aclose watch and record are kept as a check against further deterioration andspreading of the ice formation, no immediate action is required. If the coldspot is extensive, or tending to spread rapidly, flooding of the ballast spaceshould be carried out. The thermal capacity of the water, plus the improvedheat transfer from outside, should maintain the steel temperature at, or near,the ambient sea water temperature. In the unlikely event that this remedy isinsufficient and it is considered unsafe to delay discharge of cargo until arrivalat the discharge port, the final recourse will be to jettison the cargo via aportable nozzle fitted to one of the midships liquid manifolds, using a singlemain cargo pump.



Issue: 1 1.4 Hazardous Areas and Gas Dangerous Zone Plan Page 1 of 2

3m R3m R3m R

3m R

3m R3m R

1.4a Hazardous Areas and Gas Dangerous Zones

25m From AirInlet

B.O.G.To E.R.


1.4 Hazardous Areas and Gas Dangerous Zone(See illustration 1.4a)

Under the IMO code for the Construction and Equipment of Ships CarryingGases in Bulk:

Gas-dangerous spaces or zones, are zones on the open deck within 3.0 metresof any cargo tank outlet, gas or vapour outlet, cargo pipe flange, cargo valveand entrances and ventilation openings to the cargo compressor house.

The entire cargo piping system and cargo tanks are also considered gas-dangerous.

In addition to the above zones, the Code defines other gas-dangerous spaces.

The area around the air-swept trunking, in which the gas fuel line to the engineroom is situated, is not considered a gas-dangerous zone under the above Code.

All electrical equipment used in these zones, whether a fixed installation orportable, is certified ‘safe type equipment’. This includes intrinsically safeelectrical equipment, flame-proof type equipment and pressurised enclosuretype equipment. Exceptions to this requirement apply when the zones havebeen certified gas free, e.g. during refit.

Issue: 1 1.4 Hazardous Areas and Gas Dangerous Zone Plan Page 2 of 2


Part 2Properties of LNG

Properties of LNG

2.1 Physical Properties, Composition and Characteristics of LNG

Natural gas is a mixture of hydrocarbon which, when liquefied, forms a clearcolourless and odourless liquid; this LNG is usually transported and stored ata temperature very close to its boiling point at atmospheric pressure (approxi-mately –160°C).

The actual composition of Qatar LNG will vary depending on its source andon the liquefaction process, but the main constituent will always be methane;other constituents will be small percentages of heavier hydrocarbons, e.g.ethane, propane, butane, pentane, and possibly a small percentage of nitrogen.

A typical composition of LNG is given in Table 2.1b, and the physicalproperties of the major constituent gases are given in Table 2.1a.

For most engineering calculations (eg. piping pressure losses) it can beassumed that the physical properties of pure methane represent those of LNG.However, for custody transfer purposes when accurate calculation of theheating value and density is required, the specific properties based on actualcomponent analysis must be used.

During a normal sea voyage, heat is transferred to the LNG cargo through thecargo tank insulation causing vaporization of part of the cargo, ie. boil-off.

The composition of the LNG is changed by this boil-off because the lightercomponents having lower boiling points at atmospheric pressure vaporize first;therefore the discharged LNG has a lower percentage content of nitrogen andmethane than the LNG as loaded, and a slightly higher percentage of ethane,propane and butane, due to methane and nitrogen boiling off in preference tothe heavier gases.

The flammability range of methane in air (21% oxygen) is approximately 5.3to 14% (by volume). To reduce this range the air is diluted with nitrogen untilthe oxygen content is reduced to 5% prior to loading after dry dock. In theory,an explosion cannot occur if the O2 content of the mixture is below 13%regardless of the percentage of methane, but for practical safety reasons,purging is continued until the O2 content is below 5%. This safety aspect isexplained in detail later in this section.

The boil-off vapour from LNG is lighter than air at vapour temperatures above-110°C or higher depending on LNG composition (see graph 2.2a), thereforewhen vapour is vented to atmosphere, the vapour will tend to rise above thevent outlet and will be rapidly dispersed. When cold vapour is mixed withambient air the vapour-air mixture will appear as a readily visible white clouddue to the condensation of the moisture in the air. It is normally safe to assumethat the flammable range of vapour-air mixture does not extend significantlybeyond the perimeter of the white cloud.

The auto-ignition temperature of methane, ie. the lowest temperature to whichthe gas needs to be heated to cause self-sustained combustion without ignitionby a spark or flame, is 595°C.

Table 2.1b Composition of Qatar LNG

Table 2.1c Properties of Methane

Issue: 1 2.1 Properties of LNG Page 1 of 2

Table 2.1a Physical Properties of LNG

Qatar Oman StandardMethane CH4 89.53% 87.90% 89.49%Ethane C2H6 6.29% 7.26% 6.33%Propane n-C3H8 2.15% 2.89% 2.49%Butane n-C4H10 1.18% 1.68% 1.34%iso-Butane i-C4H10 0.00% 0.00% 0.00%Pentane n-C5H12 0.02% 0.00% 0.00%iso-Pentane i-C5H12 0.00% 0.00% 0.00%Nitrogen N2 0.82% 0.27% 0.34%Average molecular weight 18.09 18.56 18.19Boiling point at atmospheric pressure -160.8 -161.0 -160.9Density kg/m3 461.1 469 468.6Higher specific energy kJ/kg 54100 54061 54260

Boiling point at 1 bar absolute -161.5 °CLiquid density at boiling point 426.0 kg/m3

Vapour SG at 15°C and 1 bar absolute 0.554Gas volume/liquid volume ratio at -161.5°C at 1 bar absolute 619Flammable limits in air by volume 5.3 to 14 %Auto-ignition temperature 595 °CHigher Specific Energy (Gross Heating Value) at 15°C 5550 kJ/kgCritical temperature -82.5 °CCritical pressure 43 bar a

Methane Ethane Propane Butane Pentane NitrogenCH4 C2H6 C3H8 C4H10 C5H12 N2

Molecular weight 16.042 30.068 44.094 58.120 72.150 28.016Boiling point at 1 bar absolute °C -161.5 -88.6 -42.5 -5 36.1 -196°CLiquid density at boiling point kg/m3 426.0 544.1 580.7 601.8 610.2 808.6Vapour SG at 15°C and 1 bar absolute 0.554 1.046 1.540 2.07 2.49 0.97Gas volume/liquid volume ratio at boiling point and1 bar absolute

619 413 311 311 205 649

Flammable limits in air by volume % 5.3 to 14 3 to 12.5 2.1 to 9.5 2 to 9.5 3 to 12.4 Non-flammable

Auto - ignition temperature °C 595 510 510/583 510/583Gross heating value at 15°C normal- Iso -

kJ/kg 55559 51916 50367 4953049404

4906948944

Vaporization heat at boiling point kJ/kg 510.4 489.9 426.2 385.2 357.5 199.3


Variation of Boiling Point of Methane with Pressure

See Fig 2.1d Variation of Boiling Point of Methane with Pressure.

The boiling point of methane increases with pressure, and this variation isshown in the diagram for pure methane over the normal range of pressures onboard the vessel. The presence of the heavier components in LNG increases theboiling point of the cargo for a given pressure.

The relationship between boiling point and pressure of LNG will approxi-mately follow a line parallel to that shown for 100% methane.

Issue: 1 2.1 Properties of LNG Page 2 of 2

90

95

100

105

110

115

120

125

130

-162 -161.5 -161 -160.5 -160 -159.5 -159 -158.5

PressurekPa absolute

Temperature °C

100% Methane

2.1d Boiling Point of Methane with Pressure

+20

0

- 20

- 40

- 60

1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5

- 80

-100

-120

-140

-160

Lighter than air

Ratio =Density of Methane vapour

Density of Air

(Density of air assumed to be 1.27 kg/m3 @ 15°C)

Methane vapour

temperature °C

2.1e Relative Densitiy of Methane and Air

Heavier than air


Issue: 1 2.2 Characteristics of LNG and Definitions Page 1 of 9

M

Area ABEDHnot capable of formingflammable mixturewith air

Mixtures of air and methanecannot be produced above line BEFC

0 10

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21B

E

F

20 30 40 50 60 70 80 90 100C

Methane %

Oxygen %

A H

X

N

Area EDFEflammable

D

G

Area HDFCcapable of forming flammable mixtures with air, but containingtoo much methane to explode

This diagram assumes complete mixingwhich, in practice, may not occur

! Caution

2.2a Flammability of Methane, Oxygen and Nitrogen Mixtures

Y

Z


2.2 Characteristics of LNG and Definitions

2.2.1 Flammability of Methane, Oxygen and Nitrogen Mixtures

The ship must be operated in such a way that a flammable mixture of methaneand air are avoided at all times. The relationship between gas/air compositionand flammability for all possible mixtures of methane, air and nitrogen isshown on the diagram above.

The vertical axis A-B represents oxygen-nitrogen mixtures with no methanepresent, ranging from 0% oxygen (100% nitrogen) at point A, to 21% oxygen(79% nitrogen) at point B. The latter point represents the composition ofatmospheric air.

The horizontal axis A-C represents methane-nitrogen mixtures with no oxygenpresent, ranging from 0% methane (100% nitrogen) at point A, to 100%methane (0% nitrogen) at point C.

Any single point on the diagram within the triangle ABC represents a mixtureof all three components, methane, oxygen and nitrogen, each present inspecific proportion of the total volume. The proportions of the threecomponents represented by a single point can be read off the diagram.For example, at point D :

Methane: 6.0% (read on axis A-C)

Oxygen: 12.2% (read on axis A-B)

Nitrogen: 81.8% (remainder)

The diagram consists of three major sectors:

1) The Flammable Zone Area EDF. Any mixture whose compositionis represented by a point which lies within this area is flammable.

2) Area HDFC. Any mixture whose composition is represented by apoint which lies within this area is capable of forming aflammable mixture when mixed with air, but contains too muchmethane to ignite.

3) Area ABEDH. Any mixture whose composition is represented bya point which lies within this area is not capable of forming aflammable mixture when mixed with air.

Using the DiagramAssume that point Y on the oxygen-nitrogen axis is joined by a straight line topoint Z on the methane-nitrogen axis. If an oxygen-nitrogen mixture ofcomposition Y is mixed with a methane-nitrogen mixture of composition Z,the composition of the resulting mixture will at all times be represented bypoint X, which will move from Y to Z as increasing quantities of mixture Z areadded.

(Note! That in this example point X, representing changing composition,passes through the flammable zone EDF, that is, when the methane content ofthe mixture is between 5.5% at point M, and 9.0% at point N.)

Applying this to the process of inerting a cargo tank prior to cooldown, assumethat the tank is initially full of air at point B. Nitrogen is added until the oxygencontent is reduced to 13% at point G. The addition of methane will cause themixture composition to change along the line GDC which, it will be noted,does not pass through the flammable zone, but is tangential to it at point D. Ifthe oxygen content is reduced further, before the addition of methane, to anypoint between 0% and 13%, that is, between points A and G, the change incomposition with the addition of methane will not pass through the flammablezone.

Theoretically, therefore, it is only necessary to add nitrogen to air wheninerting until the oxygen content is reduced to 13%. However, the oxygencontent is reduced to 5% during inerting because, in practice, complete mixingof air and nitrogen may not occur.

When a tank full of methane gas is to be inerted with nitrogen prior to aeration,a similar procedure is followed. Assume that nitrogen is added to the tankcontaining methane at point C until the methane content is reduced to about14% at point H. As air is added, the mixture composition will change alongline HDB, which, as before, is tangential at D to the flammable zone, but doesnot pass through it. For the same reasons as when inerting from a tankcontaining air, when inerting a tank full of methane it is necessary to go wellbelow the theoretical figure to a methane content of 5% because completemixing of methane and nitrogen may not occur in practice.

The procedures for avoiding flammable mixtures in cargo tanks and piping aresummarised as follows:

a) Tanks and piping containing air are to be inerted with nitrogenbefore admitting methane until all sampling points indicate 5% orless oxygen content;

b) Tanks and piping containing methane are to be inerted withnitrogen before admitting air until all sampling points indicate 5%methane.

It should be noted that some portable instruments for measuring methanecontent are based on oxidising the sample over a heated platinum wire andmeasuring the increased temperature from this combustion. This type ofanalyser will not work with methane-nitrogen mixtures that do not containoxygen. For this reason, special portable instruments of the infrared type havebeen developed and supplied to the ship for this purpose.

Behaviour of LNG in the Cargo Tanks

When loaded in the cargo tanks, the pressure of the vapour phase is maintainedsubstantially constant, slightly above atmospheric pressure.

The external heat passing through the tank insulation generates convectingcurrents within the bulk cargo, heated LNG rises to the surface and is boiledoff.

The heat necessary to the vaporization comes from the LNG, and as long as thevapour is continuously removed by maintaining the pressure as substantiallyconstant, the LNG remains at its boiling temperature.

If the vapour pressure is reduced by removing more vapour than generated, theLNG temperature will decrease. In order to make up the equilibrium pressurecorresponding to its temperature, the vaporization of LNG is accelerated,resulting in an increased heat transfer from LNG to vapour.

If the vapour pressure is increased by removing less vapour than generated, theLNG temperature will increase. In order to reduce the pressure to a level cor-responding to the equilibrium with its temperature, the vaporization of LNG isslowed down and the heat transfer from LNG to vapour, reduced.

LNG is a mixture of several components with different physical properties,particularly the vaporization heat: the more volatile fraction of the cargovaporizes at a greater rate than the less volatile fraction. The vapour generatedby the boiling of the cargo contains a higher concentration of the more volatilefraction than the LNG.

The properties of the LNG i.e. the boiling point, density and heating value,have a tendency to increase during the voyage.



LNG, Nitrogen and Inert GasPhysics of GasesThis chapter provides some basic information on chemistry of gases in general.It is expected to give an outline of the important physical and chemicalproperties of liquid gases.

Gas LawsAlthough strictly speaking a perfect gas is an ideal which can never be realisedin practice, the behaviour of many real gases is very similar to the behaviourof a perfect gas. Two of the laws describing the behaviour of perfect gases areBoyle’s Law and Charles’ Law.

Boyle’s LawThis law may be stated as follows:Provided the temperature T of a perfect gas remains constant, then the volumeV of the gas is inversely proportional to its pressure P, ie.

P x V = constantif the temperature remains constant.

If a gas changes from a state 1 to a state 2 during a constant temperatureprocess (isothermal), then

P1 x V1 = P2 x V2 = constant

If the process is represented on a graph having axes of pressure P and volumeV, the result will be as shown in the figure above. The curve is known as arectangular hyperbola, having the mathematical equation:

xy = constant

Charles’ Law (Gay Lussac’s Law)Provided the pressure P of a given mass of gas remains constant, then thevolume V of the gas will be directly proportional to the absolute temperatureT of the gas, ie.

V = constant x T.

Therefore = constant for constant pressure P.

If a gas changes from state 1 to 2 during a constant pressure process, then

= = constant

If the process is represented on a P - V diagram, the result will be as shown inthe figure above.

Combination of the Laws of Boyle and CharlesThe pressure, volume and temperature of a gas may all change at once from P1V1 and T1 to P2 V2 and T2. In this case, because pressure changes, Charles’Law will not apply and because the temperature changes, Boyle’s Law willalso not apply.

This change of state may therefore be regarded as taking place in two stages:

By a change according to Boyle’s Law;

A change according to Charles’ Law.

By doing this it will be found that the following will apply

This result may be expressed thus: The product of the pressure and volume ofa quantity of gas divided by its absolute temperature is a constant and this maybe written as

= C or PV = CT where C is a constant.

Dalton’s Law of Partial PressuresThe sum of the partial pressure of the constituent gases of a mixture of gasesis equal to the total pressure of the gas mixture.

P = P1 + P2 + Pn

DefinitionsAbsolute Pressure (abs.)The total pressure of a gas called Absolute Pressure is the sum of gaugepressure plus the barometric or atmospheric pressure.

Absolute TemperatureThe fundamental temperature scale with its zero at absolute zero and expressedin degrees Kelvin. One degree Kelvin is equal to one degree Celsius or onedegree Centigrade. For the purpose of practical calculations in order to convertCelsius to Kelvin add 273. It is normal for the degree Kelvin to be abbreviatedin mathematical formulae to ‘K’ with the degree symbol being omitted.

Absolute ZeroThe temperature at which the volume of a gas theoretically becomes zero andall thermal motion ceases. It is generally accepted as being -273.16°C.

Activated AluminaA desiccant (or drying) medium which operates by adsorption of watermolecules.

AdiabaticDescribes an ideal process undergone by a gas in which no gain or loss of heatoccurs.

Aerating Aerating means the introduction of fresh air into a tank with the object ofremoving toxic, flammable and inert gases and increasing the oxygen contentto 21% by volume.

Airlock A separation area used to maintain adjacent areas at a pressure differential. Forexample, the airlock to an electric motor room on a gas carrier is used tomaintain pressure segregation between a gas-dangerous zone on the open deckand the gas-safe motor room which is pressurised.



P1V1

T1

P2V2

T2=

P2

V1 V2

P1

P

V

1

2

Boyle's Law

P

V0

1 2

Charles Law

V1

T1

V2

T2

VT

PVT

Approved Equipment Equipment of a design that has been type-tested and approved by anappropriate authority such as a governmental agency or classification society.Such an authority will have certified the particular equipment as safe for use ina specified hazardous atmosphere.

Auto-Ignition TemperatureThe lowest temperature at which a solid, liquid or gas combusts spontaneous-ly without initiation by spark or flame.

Avogadro’s Law Avogadro’s Hypothesis states that equal volumes of all gases contain equalnumbers of molecules under the same conditions of temperature and pressure..

BLEVEThis is the abbreviation for a Boiling Liquid Expanding Vapour Explosion. Itis associated with the rupture, under fire conditions, of a pressure vesselcontaining liquefied gas.

Boil-OffBoil-off is the vapour produced above the surface of a boiling cargo due toevaporation. It is caused by heat ingress or a drop in pressure.

Boiling PointThe temperature at which the vapour pressure of a liquid is equal to thepressure on its surface. The boiling point varies with pressure.

Booster PumpA pump used to increase the discharge pressure from another pump such as acargo pump.

British Thermal UnitThe quantity of heat required to raise 1 pound of water through one degreeFahrenheit, expressed in Btu.

Bulk CargoCargo carried as a liquid in cargo tanks and not shipped in drums, containersor packages.

CalorieThe quantity of heat required to raise 1 gramme (1g) of water through 1°C. Akilo calorie is equal to 1000 calories.In the ISO system, the unit used is the JOULE (J).

1 calorie (cal) 4.185J1 thermie (th) = 106 cal

Calorific ValueThe calorific value or heat of combustion is defined as the amount of heatreleased when a unit quantity of gas is burned at atmospheric pressure and atambient temperature (25°C). The gross value is obtained when the contribution

from the latent heat of condensation of the water vapour formed is recovered;the net calorific value is a more realistic parameter pertaining to practicalconditions when flue gases are usually maintained above 100°C. However, thegross heating value is the standard adopted almost universally for thecalculation of thermal efficiencies of fuel burning appliances.

Canister Filter RespiratorA respirator consisting of mask and replaceable canister filter through whichair mixed with toxic vapour is drawn by the breathing of the wearer and inwhich the toxic elements are absorbed by activated charcoal or other material.A filter dedicated to the specific toxic gas must be used. Sometimes thisequipment may be referred to as cartridge respirator. It should be noted that acanister filter respirator is not suitable for use in an oxygen deficientatmosphere.

CarcinogenA substance capable of causing cancer.

Cargo AreaThat part of the ship which contains the cargo containment system, cargopumps and compressor rooms, and includes the deck area above the cargocontainment system. Where fitted, cofferdams, ballast tanks and void spaces atthe after end of the aftermost hold space or the forward end of the forward mosthold space are excluded from the cargo area. Refer to the Gas Codes for a moredetailed definition.

Cargo Containment SystemThe arrangement for containment of cargo including, where fitted, primary andsecondary barriers, associated insulations, interbarrier spaces and the structurerequired for the support of these elements. Refer to the Gas Codes for a moredetailed definition.

Cascade Reliquifaction CycleA process in which vapour boil-off from the cargo tanks is condensed in acargo condenser in which the coolant is a refrigerant gas such as R 22. Therefrigerant gas is then compressed and passed through a conventional seawater-cooled condenser.

CavitationA process occurring within the impeller of a centrifugal pump when pressureat the inlet to the impeller falls below that of the vapour pressure of the liquidbeing pumped. The bubbles of vapour which are formed collapse withimpulsive force in the higher pressure regions of the impeller. This effect cancause significant damage to the impeller surfaces and, furthermore, pumpsmay lose suction.

Certificate of FitnessA certificate issued by a flag administration confirming that the structure,equipment, fittings, arrangements and materials used in the construction of a

gas carrier are in compliance with the relevant Gas Code. Such certificationmay be issued on behalf of the administration by an approved classificationsociety.

Certified Gas FreeA tank or compartment is certified to be gas-free when its atmosphere has beentested with an approved instrument and found in a suitable condition by anindependent chemist. This means it is not deficient in oxygen and sufficientlyfree of toxic or flammable gas for a specified purpose.

CofferdamThe isolating space on a ship between two adjacent steel bulkheads or decks.This space may be a void space or ballast space.

Compression RatioThe ratio of the absolute pressure at the discharge from a compressor dividedby the absolute pressure at the suction.

CondensateReliquified gases which collect in the condenser and which are then returnedto the cargo tanks.

Critical DensityDensity at critical temperature and pressure.

Critical Pressure The pressure at which a substance exists in the liquid state at its criticaltemperature. In other words it is the saturation pressure at the criticaltemperature.

Critical Temperature and PressureThe critical temperature of a gas is the temperature above which the substancecannot be liquid however great the pressure.

The critical pressure of a gas is the pressure required to compress a gas to itsliquid state at its critical temperature.

Cryogenics The study of the behaviour of matter at very low temperatures.

Dalton’s Law of Partial Pressures This states that the pressure exerted by a mixture of gases is equal to the sumof the separate pressures which each gas would exert if it alone occupied thewhole volume.



Dangerous Cargo Endorsement Endorsement issued by a flag state administration to a certificate ofcompetency of a ship’s officer allowing service on dangerous cargo carrierssuch as oil tankers, chemical carriers or gas carriers.

DensityThe density of a substance is the weight per unit volume at standardtemperature of 15°C. This is usually quoted in kg/m3 or g/cm3 or kg/dm3.

Deepwell Pump A type of centrifugal cargo pump commonly found on gas carriers. The primemover is usually an electric or hydraulic motor. The motor is usually mountedon top of the cargo tank and drives, via a long transmission shaft, through adouble seal arrangement, the pump assembly located in the bottom of the tank.The cargo discharge pipeline surrounds the drive shaft and the shaft bearingsare cooled and lubricated by the liquid being pumped.

Dew Point The temperature at which condensation will take place within a gas if furthercooling occurs.

Endothermic A process which is accompanied by the absorption of heat.

EnthalpyThe enthalpy of a mass of a substance is a measure of its thermodynamic heatcontent whether the substance is liquid or vapour or a combination of the two.Enthalpy (H) is defined as:

H = U + PV

where U is the internal energyP is the absolute pressure

and V is the total volume of the system (liquid + vapour)

EntropyThe entropy of a liquid or vapour is its enthalpy divided by the absolutetemperature. It is expressed as kilocalories per kilogramme per degree Celsius(kcal/kg/°C) and remains constant while the liquid or vapour volume changeswithout absorption or release of heat. However, entropy increases or decreasesif the material receives or surrenders heat from or to its surroundings. Over aninfinitely small change in temperature, the increase or decrease of entropy,when multiplied by the absolute temperature, gives the heat absorbed or lost bythe fluid.

Explosive LimitsThe limits of the explosive range, that is, the range between the minimum andmaximum concentrations of hydrocarbon vapour in air which form explosive(flammable) mixtures: usually abbreviated to LEL (Lower Explosive Limit)and UEL (Upper Explosive Limit). Sometimes referred to as LFL (LowerFlammable Limit) and UFL (Upper Flammable Limit).

Explosion-Proof/Flameproof EnclosureAn enclosure which will withstand an internal ignition of a flammable gas andwhich will prevent the transmission of any flame able to ignite a flammable gaswhich may be present in the surrounding atmosphere.

Flame ArrestorA device fitted in gas vent pipelines to arrest the passage of flame into enclosedspaces.

Flame ScreenA device incorporating corrosion resistant wire meshes. It is used forpreventing the inward passage of sparks (or, for a short period of time, thepassage of flame), yet permitting the outward passage of gas.

Flash PointThe lowest temperature at which a liquid gives off sufficient vapour to form aflammable mixture with air near the surface of the liquid or within theapparatus used. This is determined by laboratory testing in a prescribedapparatus.

Gas-Safe SpaceA space on a ship not designated as a gas-dangerous space.

Hard ArmAn articulated metal arm used at terminal jetties to connect shore pipelines tothe ship’s manifold.

HeelThe amount of liquid cargo retained in a cargo tank at the end of discharge. Itis used to maintain the cargo tanks cooled down during ballast voyages byrecirculating through the sprayers. On LPG ships such cooling down is carriedout through the reliquifaction plant and on LNG ships by using the spraypumps.

Hold Space The space enclosed by the ship’s structure in which a cargo containmentsystem is situated.

Hydrates The compounds formed by the interaction of water and hydrocarbons at certainpressures and temperatures. They are crystalline substances.

Hydrate Inhibitors An additive to certain liquefied gases capable of reducing the temperature atwhich hydrates begin to form. Typical hydrate inhibitors are methanol, ethanoland isopropyl alcohol.

IACS International Association of Classification Societies.

IAPH International Association of Ports and Harbours.

lCSInternational Chamber of Shipping.

IMO International Maritime Organization. This is the United Nations specialisedagency dealing with maritime affairs.

Incendive Spark A spark of sufficient temperature and energy to ignite a flammable gas mixedwith air.

Inert Gas A gas, such as nitrogen, or a mixture of gases containing insufficient oxygento support combustion.

Inerting Inerting means:

(i) The introduction of inert gas into an aerated tank with the objectof attaining an inert condition suited to a safe gassing-upoperation.

(ii)The introduction of inert gas into a tank after cargo discharge and warming-up with the object of:

Reducing existing vapour content to a level below whichcombustion cannot be supported if aeration takes place.

Reducing existing vapour content to a level suited to gassing-upprior to the next cargo.

Reducing existing vapour content to a level stipulated by localauthorities if a special gas-free certificate for hot work is required.

Insulation FlangeAn insulating device inserted between metallic flanges, bolts and washers toprevent electrical continuity between pipelines, sections of pipelines, hosestrings and loading arms or other equipment.



Interbarrier SpaceThe space between a primary and a secondary barrier of a cargo containmentsystem, whether or not completely or partially occupied by insulation or othermaterial.

Intrinsically SafeEquipment, instrumentation or wiring is deemed to be intrinsically safe if it isincapable of releasing sufficient electrical or thermal energy under normalconditions or specified fault conditions to cause ignition of a specifichazardous atmosphere in its most easily ignited concentration.

ISGOTTInternational Safety Guide for Oil Tankers and Terminals.

IsothermalDescriptive of a process undergone by an ideal gas when it passes throughpressure or volume variations without a change of temperature.

Latent HeatThe latent heat of a liquid is the quantity of heat absorbed on vaporization atnormal boiling point, or conversely, it is the amount of heat given out when thevapour is condensed at atmospheric pressure. As the heat content of the liquidincreases with temperature, the latent heat decreases.The value of latent heatdata lies in calculating the quantity of gas that will be vaporized at a givenliquid temperature by a specific heat input.

Latent Heat of VaporizationQuantity of heat to change the state of a substance from liquid to vapour (orvice versa) without change of temperature.

Liquefied GasA liquid which has a saturated vapour pressure exceeding 2.8 bar absolute at37.8°C and certain other substances specified in the Gas Codes.

Liquefied Natural Gas (LNG)Liquefied methane and mixtures of other hydrocarbon gases in which methanepredominates.

Lower Flammable Limit (LFL)The concentration of a hydrocarbon gas in air below which there is insufficienthydrocarbon to support combustion.

LPGThis is the abbreviation for Liquefied Petroleum Gas. This group of productsincludes propane and butane which can be shipped separately or as a mixture.LPGs may be refinery by-products or may be produced in conjunction withcrude oil or natural gas.

MARVSThis is the abbreviation for the Maximum Allowable Relief Valve Setting on aship’s cargo tank as stated on the ship’s Certificate of Fitness.

mlcThis is the abbreviation for metres liquid column and is a unit of pressure usedin some cargo pumping operations.

Molar VolumeThe volume occupied by one molecular mass in grams (g mole) under specificconditions. For an ideal gas at standard temperature and pressure it is 0.0224m3/g mole.

MoleThe mass that is numerically equal to the molecular mass. It is most frequentlyexpressed as the gram molecular mass (g mole) but may also be expressed inother mass units, such as the kg mole. At the same pressure and temperaturethe volume of one mole is the same for all ideal gases. It is practical to assumethat petroleum gases are ideal gases.

Mole FractionThe number of moles of any component in a mixture divided by the totalnumber of moles in the mixture.

Mollier DiagramA graphic method of representing the heat quantities contained in, and thecondition of, a liquefied gas (or refrigerant) at different temperatures.

NGLsThis is the abbreviation for Natural Gas Liquids. These are the liquidcomponents found in association with natural gas. Ethane, propane, butane,pentane and pentanes-plus are typical NGLs.

NPSHThis is the abbreviation for Net Positive Suction Head. This is an expressionused in cargo pumping calculations. It is the pressure at the pump inlet and isthe combination of the liquid head plus the pressure in the vapour space.

OCIMFOil Companies International Marine Forum.

Oxygen AnalyserInstrument used to measure oxygen concentrations in percentage by volume.

Oxygen-Deficient AtmosphereAn atmosphere containing less than 21% oxygen by volume.

Partial PressureThe individual pressure exerted by a gaseous constituent in a vapour mixtureas if the other constituents were not present. This pressure cannot be measureddirectly but is obtained firstly by analysis of the vapour and then by calculationusing Dalton’s Law.

PeroxideA compound formed by the chemical combination of cargo liquid or vapourwith atmospheric oxygen or oxygen from another source. In some cases thesecompounds may be highly reactive or unstable and a potential hazard.

PolymerisationThe chemical union of two or more molecules of the same compound to forma larger molecule of a new compound called a polymer. By this mechanism thereaction can become self-propagating causing liquids to become more viscousand the end result may even be a solid substance. Such chemical reactionsusually give off a great deal of heat.

Primary BarrierThis is the inner surface designed to contain the cargo when the cargocontainment system includes a secondary barrier.

Other refrigerant gases listed in the IGC Code are shown in Appendix 2although many are now controlled with a view to being phased out under theMontreal Protocol (1987).

Relative Liquid DensityThe mass of a liquid at a given temperature compared with the mass of anequal volume of fresh water at the same temperature or at a different giventemperature.

Relative Vapour DensityThis is the relative weight of vapour compared with the weight of an equalvolume of dry air at standard conditions of temperature and pressure, ie 15°Cand atmospheric pressure of 760mm Hg.

Restricted GaugingA system employing a device which penetrates the tank and which, when inuse, permits a small quantity of cargo vapour or liquid to be expelled to theatmosphere. When not in use, the device is kept completely closed.

Rollover The phenomenon where the stability of two stratified layers of liquid ofdiffering relative density is disturbed resulting in a spontaneous rapid mixingof the layers accompanied in the case of liquefied gases, by violent vapourevolution.



Saturation TemperatureThe saturation temperature is that at which boiling occurs. At this temperaturebubbles of vapour form in the liquid and break through the surface to occupythe space above it as a vapour. Supply of heat at this temperature causes furthergeneration of vapour but does not increase the temperature until all the liquidhas been converted into a vapour. Another definition of saturation temperatureis that it is the temperature at which the two phases, liquid and vapour, canexist in equilibrium with each other. As the pressure is increased so is thesaturation temperature, until the critical point is reached.

Saturated Vapour PressureThe pressure at which a vapour is in equilibrium with its liquid at a specifiedtemperature.

Secondary BarrierThe liquid-resisting outer element of a cargo containment system designed toprovide temporary containment of a leakage of liquid cargo through theprimary barrier and to prevent the lowering of the temperature of the ship’sstructure to an unsafe level.

Sensible HeatHeat energy given to or taken from a substance which raises or lowers itstemperature.

Shell and Tube CondenserA heat exchanger where one fluid circulates through tubes enclosed betweentwo end-plates in a cylindrical shell and where the other fluid circulates insidethe shell.

Silica GelA chemical used in driers to absorb moisture.

Sl (Systeme International) UnitsAn internationally accepted system of units modelled on the metric systemconsisting of units of length (metre), mass (kilogram), time (second), electriccurrent (ampere), temperature (degrees Kelvin) and amount of substance(mole).

SIGTTO Society of International Gas Tanker and Terminal Operators Limited.

Slip Tube A device used to determine the liquid/vapour interface during the ullaging ofsemi and fully pressurised tanks.

SOLAS International Convention for the Safety of Life at Sea, 1974; as amended.

Span GasA vapour sample of known composition and concentration used to calibrategas detection equipment.

Specific Gravity (SG)The specific gravity of a gas is normally defined as the ratio of its density tothat of air at the same temperature and pressure (taken as unity).

Specific gravity of liquids expresses the relative weight of these hydrocarbonliquids at their boiling point as compared to water at 4°C.

Specific HeatThis is the quantity of energy in kilo Joules required to change the temperatureof 1kg mass of a substance by 1°C. For a gas the specific heat at constantpressure is greater than that at constant volume.

Specific VolumeThis is the volume occupied by one kg of the substance at 15°C and 760mmHg pressure.

Spontaneous CombustionThe ignition of material brought about by a heat-producing chemical reactionwithin the material itself without exposure to an external source of ignition.

Static ElectricityStatic electricity is the electrical charge produced on dissimilar materialscaused by relative motion between each when in contact.

Submerged PumpA type of centrifugal cargo pump commonly installed on gas carriers and interminals in the bottom of a cargo tank. It comprises a drive motor, impellerand bearings totally submerged by the cargo when the tank contains bulkliquid.

Superheated VapourVapour removed from contact with its liquid and heated beyond its boilingtemperature.

Surge PressureA phenomenon generated in a pipeline system when there is a change in therate of flow of liquid in the line. Surge pressures can be dangerously high if thechange of flow rate is too rapid and the resultant shock waves can damagepumping equipment and cause rupture of pipelines and associated equipment.

ThermThe therm is equal to 100,000 Btu.

Toxicity DetectorAn instrument used for the detection of gases or vapours. It works on theprinciple of a reaction occurring between the gas being sampled and a chemicalagent in the apparatus.

TLVThis is the abbreviation for Threshold Limit Value. It is the concentration ofgases in air to which personnel may be exposed 8 hours per day or 40 hoursper week throughout their working life without adverse effects. The basic TLVis a Time-Weighted Average (TWA). This may be supplemented by a TLV-STEL (Short-Term Exposure Limit) or TLV-C (Ceiling exposure limit) whichshould not be exceeded even momentarily.

Viscosity (Kinematic)The property of a liquid which determines its resistance to flow. The usefulnessof viscosity data lies in specifying pumps for liquid transfer and in predictingpressure losses in pipe systems.

The unit used is the stoke (St) or centistoke (cSt).

Vapour DensityThe density of a gas or vapour under specified conditions of temperature andpressure.

Void SpaceAn enclosed space in the cargo area external to a cargo containment system,other than a hold space, ballast space, fuel oil tank, cargo pump or compressorroom or any space in normal use by personnel.




Illustration 2.2.2a Temperature and Steel Grades

Double Hull and Compartment Temperatures& Steel Grade Selection in way of Tanks No.2, 3, 4

Double Hull and Compartment Temperaturesand Steel Grade Selection in way of Tank No.1

LNG On Secondary Barrier

For Inner HullAir Temperature = -18oC

Sea Water Temperature = 0oCWind Speed = 5 Knots

For Outer HullAir Temperature = 5oC


Air Temperature Inside Compartment

Inner Hull Steel Plating Temperature

-1.3

-2.8

oC

-22

-22

-13

-22

-54

-4.2

-25

-5.7

oC

-25

+0.5

-15

+1.2

Cofferdam WithHeating

Dimensioning case forheating system andfull redundancyie 2 x 100% capacity

CofferdamWithout Heating -57

+5

0

Insulation Thickness Secondary = 0.170m + Primary = 0.080m --------------- 0.250m

LNG CargoTemperature = -163oC

Grade B

Grade B

Grade A Grade D

Grade A

Grade A

Grade E

Grade E

Grade A

Grade AGrade E

Grade A

Grade E

Grade E

Grade E

Grade E

Grade D

Grade D

Grade B

Grade B

Grade B

Grade B

Grade A Grade D

Grade A

Grade A

Grade E

Grade E

Grade A

Grade AGrade E

Grade A

Grade E

Grade E

Grade E

Grade E

Grade D

Grade D

Grade B

Grade B

LNG On Secondary BarrierSteel Grade Selection Steel Grade Selection

For Inner HullAir Temperature = -18oC


For Outer HullAir Temperature = 5oC


Air Temperature Inside Compartment

Inner Hull Steel Plating Temperature

-1.0

-2.8

oC

-21

-22

-13

-22

-53

-4.2

-25

-5.7

oC

-26

+0.5

-15

-15

+1.8

+0.9

+0.9

Cofferdam WithHeating

Dimensioning case forheating system andfull redundancyie 2 x 100% capacity

CofferdamWithout Heating -55

+5

0

0

0

+1.0

+1.0

0

0

Insulation Thickness Secondary = 0.170m + Primary = 0.080m --------------- 0.250m

LNG CargoTemperature = -163oC


Issue: 1 2.3 Health Hazards Page 1 of 2

THE MAIN HAZARDFLAMMABLE.

METHANEFORMULA CH4

U.N. NUMBER 2043

FAMILY Hydrocarbon

APPEARANCE Colourless

ODOUR Odourless

EMERGENCY PROCEDURES

FIRE Stop gas supply. Extinguish with dry powder, Halon or CO2. Cool surrounding area with water spray.

LIQUID DO NOT DELAY. Flood eye gently with clean fresh/sea water. Force eye open if necessary.

IN EYE Continue washing for 15 minutes. Obtain medical advice/assistance.

LIQUID DO NOT DELAY. Treat patient gently. Remove contaminated clothing. Immerse frostbitten area

ON SKIN in warm water until thawed (see Chapter 9). Obtain medical advice/assistance.

VAPOUR Remove victim to fresh air. If breathing has stopped, or is weak/irregular, give mouth-to-mouth/nose

INHALED resuscitation.

SPILLAGE Stop the flow. Avoid contact with liquid or vapour. Flood with large amounts of water to disperse spill andprevent brittle fracture. Inform Port Authorities of any major spill.

EFFECT OF LIQUID

EFFECT OF VAPOUR

Frostbite to skin or eyes. Not absorbed through skin.

Asphyxiation - headache, dizziness, drowsiness. Possible low temperature damage to lungs, skin. Nochronic effect known.

PHYSICAL DATA

FIRE AND EXPLOSION DATA

BOILING POINT @ ATMOSPHERIC -161.5˚CPRESSUREVAPOUR PRESSURE See graphskg/cm2 (A)

SPECIFIC GRAVITY 0.42

COEFFICIENT OF CUBIC EXPANSION 0.0026 per ˚C @ -165˚C

RELATIVE VAPOUR DENSITY 0.554

MOLECULAR 16.04WEIGHT

ENTHALPYLiquid Vapour

(kcal/kg)7.0 @ -165˚C 130.2 @ -165˚C

68.2 @ -100˚C 140.5 @ -100˚CLATENT HEAT OF VAPOURISATION See graphs(kcal/kg)

FLASH POINT -175˚C (approx) FLAMMABLE LIMITS 5.3 -14% AUTO-IGNITION TEMPERATURE 595˚C

HEALTH DATE

TVL 1000 ppm ODOUR THRESHOLD Odourless

“fire damp”“marsh gas”LNG

2.3 Health HazardsREACTIVITY DATA METHANE

AIR

WATER(Fresh/Salt)

OTHER LIQUIDS/GASES

No reaction.

No reaction. Insoluble. May freeze to form ice or hydrates.

Dangerous reaction possible with chlorine.

CONDITIONS OF CARRIAGE

NORMALCARRIAGECONDITIONS

SHIP TYPE

Fully refrigerated.

2G.

GAUGING

VAPOUR DETECTION

Closed, indirect.

Flammable.

MATERIALS OF CONSTRUCTION

UNSUITABLE SUITABLE

Stainless steel, aluminium, 9 or 36% nickel steel, copper.

SPECIAL REQUIREMENTS

Mild steel.


Issue: 1 2.3 Health Hazards Page 2 of 2

THE MAIN HAZARDFROSTBITE.

NITROGENFORMULA N2

U.N. NUMBER 2040

FAMILY Noble Gas

APPEARANCE Colourless

ODOUR Odourless

EMERGENCY PROCEDURES

FIRE Non-flammable. Cool area near cargo tanks with water spray in the event of fire near to them.

LIQUID DO NOT DELAY. Flood eye gently with clean sea/fresh water. Force eye open if necessary.

IN EYE Continue washing for 15 minutes. Seek medical advice/assistance.

LIQUID DO NOT DELAY. Handle patient gently. Remove contaminated clothing. Immerse frostbitten area

ON SKIN in warm water until thawed (see Chapter 9). Obtain medical advice/assistance.

VAPOUR Remove victim to fresh air. If breathing has stopped, or is weak/irregular, give mouth-to-mouth/nose

INHALED resuscitation.

SPILLAGE Stop the flow. Avoid contact with liquid or vapour. Flood with large amounts of water to disperse spill andprevent brittle fracture. Inform Port Authorities of any major spillage.

EFFECT OF LIQUID

EFFECT OF VAPOUR

Frostbite to skin or eyes.

Asphyxiation. Cold vapour could cause damage.

PHYSICAL DATA

FIRE AND EXPLOSION DATA

BOILING POINT @ ATMOSPHERIC -195.8˚CPRESSUREVAPOUR 2 @ -190˚C PRESSURE 10 @ -170˚Ckg/cm2 (A)

SPECIFIC GRAVITY 0.9

COEFFICIENT OF CUBIC EXPANSION 0.005 @ -198˚C

RELATIVE VAPOUR DENSITY 0.967

MOLECULAR 28.01WEIGHT

ENTHALPYLiquid Vapour

(kcal/kg)7.33 @ -196˚C 54.7 @ -195˚C

34.7 @ -150˚C 52.0 @ -150˚CLATENT HEAT OF VAPOURISATION

47.5 @ -196˚C

(kcal/kg) 17.3 @ -150˚C

FLASH POINT Non-flammable FLAMMABLE LIMITS Non-flammable AUTO-IGNITION TEMPERATURE Non-flammable

HEALTH DATE

TVL 1,000 ppm ODOUR THRESHOLD Odourless

REACTIVITY DATA NITROGEN

AIR

WATER(Fresh/Salt)

OTHER LIQUIDS/GASES

No reaction.

No reaction. Insoluble.

No reactions.

CONDITIONS OF CARRIAGE

NORMALCARRIAGECONDITIONS

SHIP TYPE

Fully refrigerated.

3G.

GAUGING

VAPOUR DETECTION

Closed, indirect.

Oxygen analyser required.

MATERIALS OF CONSTRUCTION

UNSUITABLE SUITABLE

Stainless steel, copper, aluminium.

SPECIAL REQUIREMENTS

High oxygen concentrations can be caused by condensation and enrichment of the atmosphere in way of equipment at the lowtemperatures attained in parts of the liquid nitrogen system; materials of construction and ancillary equipment (e.g. insulation)should be resistant tot he effects of this. Due consideration should be given to ventilation in areas where condensation mightoccur to avoid the stratification of oxygen-enriched atmosphere.

Mild steel.


2.2.2 Supplementary Characteristics

When Spilled on Water:

1) Boiling of LNG is rapid due to the large temperature difference between theproduct and water.

2) LNG continuously spreads over an indefinitely large area, it results in amagnification of its rate of evaporation until vaporization is complete.

3) No coherent ice layer forms on the water.

4) Under particular circumstances, with a methane concentration below 40%,flameless explosions are possible when the LNG strikes the water. It resultsfrom an interfacial phenomenon in which LNG becomes locally superheated ata maximum limit until a rapid boiling occurs. However, commercial LNG isfar richer in methane than 40% and would require Iengthy storage beforeageing to that concentration.

5) The flammable cloud of LNG and air may extend for large distancesdownward (only methane when warmer than -100°C is lighter than air)because of the absence of topographic features which normally promoteturbulent mixing.

Vapour Clouds1) If there is no immediate ignition of an LNG spill, a vapour cloud may form.The vapour cloud is long, thin, cigar shaped and, under certain meteorologicalconditions, may travel a considerable distance before its concentration fallsbelow the lower flammable limit. This concentration is important, for the cloudcould ignite and burn, with the flame travelling back towards the originatingpool. The cold vapour is denser than air and thus, at least initially, hugs thesurface. Weather conditions largely determine the cloud dilution rate, with athermal inversion greatly lengthening the distance travelled before the cloudbecomes nonflammable.

2) The major danger from an LNG vapour cloud occurs when it is ignited. Theheat from such a fire is a major problem. A deflagrating (simple burning) isprobably fatal to those within the cloud and outside buildings but is not a majorthreat to those beyond the cloud, though there will be burns from thermalradiations.

3) When loaded in the cargo tanks, the pressure of the vapour phase ismaintained as substantially constant, slightly above atmospheric pressure.

4) The external heat passing through the tank insulation generates convectingcurrents within the bulk cargo, heated LNG rises to the surface and boils.

5) The heat necessary for the vaporization comes from the LNG and, as longas the vapour is continuously removed by maintaining the pressure as substan-tially constant, the LNG remains at its boiling temperature.

6) If the vapour pressure is reduced by removing more vapour than generated,the LNG temperature will decrease. In order to make up the equilibriumpressure corresponding to its temperature, the vaporization of LNG isaccelerated resulting in an increased heat transfer from LNG to vapour.

ReactivityMethane is an asphyxiant in high concentrations because it dilutes the amount ofoxygen in the air below that necessary to maintain life. Due to its inactivity,methane is not a significant air pollutant, and due to its insolubility, inactivity,and volatility it is not considered a water pollutant.

Cryogenic TemperaturesContact with LNG or with materials chilled to its temperature of about -160°Cwill damage living tissue.

Most metals lose their ductility at these temperatures; LNG may cause thebrittle fracture of many materials. In case of LNG spillage on the ship’s deck,the high thermal stresses generated from the restricted possibilities ofcontraction of the plating result in the fracture of the steel. The illustration2.2.2a shows a typical ship section with the minimum acceptable temperaturesof the steel grades selected for the various parts of the structure.



Part 3Integrated Automation System (IAS)

Issue: 1


Integrated Automation System (IAS)

3.1 Centralised Administration and Control Centre (CACC)Arrangement

This ship is provided with a Centralised Administration and Control Centre(CACC) on D-deck. Normal control of all cargo and machinery operations iscarried out from here.

The ship’s IAS (see 3.2) is used for all normal and some emergency operationsincluding monitoring, planning, control and alarm functions. The main CACCconsole is split into cargo (port side) and machinery (starboard side) sections.

A computer room on the starboard side is used for administrative functions.Here are installed the SMS (ship management system) terminals etc.

The Cargo Hard Mimic board is located on the aft bulkhead to the rear of thecargo console. It indicates valve positions but does not allow control.

3.1 Centralised Administration and Control Centre Arrangement Page 1 of 1

Issue: 1

Illustration 3.2.1a IAS OverviewWheelhouse Console

Universal Station

TrainingConsole

Local ControlNetwork

ExpanderESCR

Console

Duplex FibreOptic Link

UCN

No.2Boiler

KHI Boiler System ACC

NetworkInterfaceModule

History Module(442Mb HardDisk Unit x 2)

Universal Control Network

FTA FTA FTA FTA FTA FTA

SMSCargo

SMSMachinery

Float LevelGaugesShip Performance

ComputerLoading

ComputerCustodyTransfer

Colour ScreenHard Copy

Colour ScreenHard CopyAlarmLogging AlarmLogging

Cargo SystemPrinters

Machinery SystemPrinters

PC NetworkInterface

PortableNotebook computer

Captain'sOffice Room

(20")

Chief Officer'sDay Room

(20")

1st Officer'sRoom(20")

2nd Officer'sDay Room

(15")

Chief Engineer's

Office Room(20")

1st Engineer'sDay Room

(20")

2nd Engineer'sRoom (15")

3rd Engineer'sRoom (15")

Ship'sOffice(15")

Gas EngineersDay Room

(20")

LAN

Local Control Network(Dual Highway)

HighPerformance

ProcessManagers

No.1Boiler

Dual HPPM

Network InterfaceModule

Network InterfaceModule

PC NetworkInterface

E

O

E

O

E

O

E

O

Universal Control Network

UCN


Dual I/OFiles

Field Transmittable

Arrays

Serial Data 5-106A 8-106A 1-103A 1-107B 8-106B 5-106B

5 sets; 20 sockets

CACC Console


Expander

E

O

E

O L.C.N

L.C.N

E

O

E

O


Expander

3.2 Integrated Automation System Page 1 of 12


3.2 Integrated Automation System

3.2.1 IAS Overview

Maker: Yamatake Industrial Systems Co. LtdType: TDC 3000 LCN

General

The Integrated Automation System (IAS) is based on the Yamatake system,previously Yamatake-Honeywell which is a distributed process control systemdeveloped from the Honeywell TDC3000.

As implemented on this ship, the IAS system controls and monitors almost allsystems and equipment on board. The functions of the IAS are as follows:

System monitoring

System control manipulating and operation

Alarm handling, summary and acceptance

Data logging and trending

Data interfaces to other systems

Control of the extension alarm system

Operation planning and control

Data output to the PC based LAN

System Architecture

The IAS system comprises:

Universal Stations - These are workstation processors with a local TDC stylekeyboard and single or dual VDU/CRT monitors.

These are located:

CACC Dual universal stations on port side for cargo

Training console Single universal station for both cargo and machineryoperations

Wheelhouse Single universal station for machinery operations

In addition there are:

CACC Dual universal stations on starboard side for machinery

ESCR Dual universal stations for machinery operations

Both sets of mimics and functions can be accessed from either universalstation. There is a QWERTY keyboard fitted under a cover which can beaccessed via a supervisor level keyboard.

HPPM - High performance process managers which convert input analoguesignals to digital and output control digital signals and analogue signals. Theseare linked by a dual data bus Universal Control Network over which all datasignals are exchanged.

These are located in the APM cabinets in the ESCR and the electric equipmentroom on C-deck.

FTA-Serial Interfaces to Other Systems

FTAs (Field Transmittable Arrays) which manage serial data exchange byModbus protocol with other systems and devices are used. These are linked tothe HPPMs located in the APM cabinets in the ESCR and the electricequipment room on C-deck.

The FTAs provide an interface to the following other systems:

Cargo

CTS Custody transfer system

LC Loading computer

FLG Float level gauging

SMS (cargo) Shipboard management system

Machinery

SPM Ship performance monitor

SMS (machy) Shipboard management system

Network Interface Modules - Link the Universal Control Network to theLocal Control Network (LCN). This in turn links all the universal stations, thePC network Interface and the History Module. The Network Interface Modulesalso link the Boiler Control System to the IAS.

These network interface modules are located in the APM cabinets in the ESCRand the electrical equipment room on C-deck and in the control consoles.

The universal control network uses fibre-optic transmission to link the ESCRconsole and the KHI boiler control sub-system to the main universal controlnetwork.

History Module

The history module is a dual hard disk unit with 2 x 442Mb disks for datastorage. It communicates with all modules on the local control network andany process connected device on the universal control networks. It storesprocess and system information as below, which can be displayed or printed atthe universal station. All analogue input data is recorded on the hard disk of thehistory module for 168 hours, automatically. The operator can call up any setsof data on the group trend display.

Continuous process history

Sample data

Averages

Event journals Process eventsSystem eventsSequence of events (fast alarms)

Active system files

Graphic display abstracts

Database checkpoints

User files

System configuration files

Static system files

Loadable software images (mimics)

Valve Position ControllerThe valve position controllers have two operation modes for manipulating theremote control valves.

Auto ModeThe system outputs open/close signals by comparing therequested valve position and the valve position feedback. Therequested valve position is set by entry of a set point value.

Man ModeThe operator can control the open/close signal directly.

Sensor Monitoring

The IAS monitors the process value of the analogue inputs. If the input fails,the system will indicate a sensor abnormal condition. Out of range inputs areshown as ‘------’

Issue: 1 3.2 Integrated Automation System Page 2 of 12


Issue: 1

C. SysOverview

C-1

H/DCompressor

C-11

3 Tk./BarrierSpace Monitor

C-21

Ope. Plan(Load/Unload)

C-31

A

K

U

Manifold(Cargo Piping)

C-2

B.O./W.U.HeaterC-12


C-22

Ope. Planning(Ballast)

C-32

B

L

V

1 / 2 C. Tk(Cargo Piping)

C-3

LNG/ForcingVapourizer

C-13

Loading(Monitor)

C-23

Ope. Planning(De-Ballast)

C-33

C

M

W

3 / 4 C. Tk(Cargo Piping)

C-4

N2Generator

C-14

Unloading(Monitor)

C-24

V.V. Fail ListFor Seq.

C-34

D

N

X

Mach. Rm(Cargo Piping)

C-5

I.G.G.UnitC-15

Ballast(Monitor)

C-25

SystemOperation

C-35

E

O

Y

Ball. SysOverview

C-6

MotorAux. 1C-16

De-Ballast(Monitor)

C-26

Ope. Index(Ope. Select)

C-36

G. M. S.Set Point

C-41

Line Up 1(Around Tank)

C-42

Line Up 2(Liq. Man/Head)

C-43

Line Up 3(Vap. Line)

C-44

Loading(Line Flow)

C-45

Ope. Guide(Load/Unload 3)

C-51

Ope. Guide(Loading 1)

C-52

Ope. Guide(Loading 2)

C-53

Unloading(Line Flow)

C-54

Ope. Guide(Unloading 2)

C-55

Inerting P/D(Ope. Flow)

C-61

Gassing Up(Ope. Flow)

C-62

Init. Cooldown(Ope. Flow)

C-63

Warm Up(Ope. Flow)

C-64

Inerting P/D(Ope. Flow)

C-65

Ope. Guide(Gassing Up 2)

C-71

Init. Cooldown(Line Flow)

C-72

Ope. GuideInit. Cooldown

C-73

Warm Up(Line Flow)

C-74

Ope. Guide(Warm Up 1)

C-75

Unloading(Ope. Flow)

C-46

F

P

Z

W.B.T.Piping

C-7

MotorAux. 2C-17

G. M. S.

C-27

G

Q

SP

W.B.Pump Piping

C-8

CLRSCREEN

CHANGEOVER

GasDetectC-18

CooldownMonitor

C-28

H

R

F/Bilge &Water Spray P.P.

C-9


C-19

G.W. System(Heating Cont.)

C-29

I

S

Hyd FanControlC-10


C-20

Barrier N2 Sys.(Press.Cont.)

C-30

J

T

AlphaShift

MSGSUMM

GROUP

SYSTSTATS

CONSSTATS

RECRD FAST CANCELPRINT

PRINTDISP

PRINTTREND

SYSTMENU

LOAD

UNITTREND

BATCH

SCHEM

DISPSET

PRIORDISP

DISPBACK

PAGEBACK

DETAIL

TREND

GO TO

HELP

HOURAVG

ASSOCDISP

DISPFWD

PAGEFWD

7

4

1

.

ENTER

ACK SIL

8

5

2

0

9 MAN

CLRENTR

SELECT

SP OUT

AUTO

TAB

NORM

TAB TAB TAB

6

3

-

MSGCONFM

MSGCLEAR

UNITALMSUM

ALARMSUMM

ALARMANNC


C-76

Ope. Guide(Gassing Up 1)

C-70

G. M. S.(Ope. Flow)

C-47

Loading(Line Flow)

C-48


C-50

Ope. Guide(Unloading 1)

C-56

Ope. Guide(Line C/D)

C-57

Ope. IGuide(G. M. S.)

C-58

S.T P/P Start Guide

C-59

C/D and Forc.InputC-60

Aeration(Ope. Flow)

C-66

Inerting P/D(Line Flow)

C-67

Ope. Guide(Inerting P/D)

C-68

Gassing Up(Line Flow)

C-69


C-77

Inert. P/D(Line Flow)

C-78

Ope. Guide(Inerting P/D)

C-79


C-49

Fresh W.Cooling Sys.

C-37

Bilge/WaterDet. Alarm

C-38

GasDetector (3)

C39

UPP VDUTREND

FASTALARM

Illustration 3.2.1b IAS Cargo Operator's Keyboard


These keys directly call up the display as labelled.

To call up other displays key in the Schematic Display Numberand press ENTER. Remember to use the ALPHA-SHIFT key.

Switches the active display between top and bottom CRTs inCACC only. Has no function on single screen UCS.

Displays the alarm summary list.

Press once and display shows previous display; press again anddisplay returns to new display.

Prints a colour Screen Dump of current display to hard copyprinter.

Press this key, and use numeric to enter group number and pressENTER - Display shows group display selected.

Use numeric to enter group number and press ENTER - Selectpoint to be trended from touch-screen. Press TREND key todisplay trend.

Active in group display, increases data update rate from 4s to 1s.

Press this key, display shows SYSTEM MENU. Use touchscreen to select item required. eg ORGANISATIONALSUMMARY accesses GROUP TITLES pages to list all groupsselectable by numeric keys.

In group screen selects Hourly Average data instead of instan-taneous data.

Has no function.

In group screen selects next or previous group screen.

Acknowledges new alarm message and removes it from thedisplay top line.

Silences audible alarm.

C. SysOverview

C-1

AlphaShift

CHANGEOVER

ALARMSUMM

PRIORDISP

PRINTDISP

Group

TREND

FAST

SYSTMENU

HOURAVG

HELP

DISPFWD

ACK

SIL

DISPBACK


Training Mode

The IAS provides a training mode for the operator to study and familiarise theuniversal station operation for control and monitoring. The training mode isprocessed in the Universal Station, Network Interface and Advanced ProcessManager Modules.

3.2.2 IAS Universal Control Station Operation

The universal station is the main operator interface to the system. It is one ofthe modules on the Local Control Network. Each station can communicatewith other modules on the LCN and with connected devices on the UniversalControl Network (UCN).

The universal station provides a single window to the entire system, whetherthe data is resident in one of the LCN modules or in one of the devices on theUCN. A single station can be used by an operator to access the followingfunctions via displays, mimic diagrams, or trending or diagnostic displays.

System and Process Operation Functions

Monitoring and manipulating operations

Display of current alarms, acceptance of alarms and summary displayof all current alarms

Displaying and printing trends, logs, journals

Monitoring and controlling system status and diagnostics

Operator Keyboard and Touch ScreenSee illustration 3.2.1b

Each universal control station has an operator keyboard for normal operation.The CRTs have a touch screen overlay for operator input. Avoid touching thescreen directly, this will smear the screen. Use a softwood pointer.

Display Layout

The top two lines are reserved for the integrated automation system, wherenew alarms, any system prompts and error messages are displayed. The dateand time are displayed at the right hand side.

The schematic display title is indicated at the top of the graphic display. Thegraphic display is composed of pipelines, pump or valve symbols, numericalvalues etc.

The bottom three lines of the display are reserved for the Change Zone. Thisarea is used for manipulating controllers, pumps and switches, which appear inthis area when the operator selects the desired object on the graphic display. Ifno object is selected, the change zone displays system titles that are availablefor selection.

Operation - Direct Keyboard

There are several levels at which the user can access functions. The main onesare listed as follows:

The keyboard has the following functions:

Directly call up information about the status of system components

Directly call up process displays at several levels of detail

Move between different displays at the same level of detail

Select items on a particular display to be manipulated

Control the process setpoint

Enter both alpha and numerical data

Operation - Target Selection

By selecting items from the graphic display their status can be altered. Pumpscan be started and stopped, placed on auto or manual and standby statusaltered. Valves can be manually opened and closed and placed on auto andmanual. Process set points can be altered.

The touch screen controls an arrow-type pointer which can be moved aroundthe screen.

When it is positioned over a control element, it will change to a flashing crosshair type pointer. Touching this will activate the control function within thechange zone. Certain displays are configured so that the target areas outlinedby a box show status of components within the IAS. Most diagnostic displaysuse this feature.

Group and Detail DisplayThese show groups of parameters and allow the operator to take actions. Theyare selected from the yellow boxes in the change zone for certain schematicsor can be selected by entry of the group number from the GROUP key. Theseare updated at 4 second intervals or 1 second when the FAST key is pressed.The graphic displays can indicate numeric values and conditions and certainvalves etc can be controlled from the touch display.



Group Trend DisplaysIf one or more group parameters is selected and TREND key is pressed, a trendgraph as shown below is displayed. Up to 8 values in the group are displayedin different colours. Variable scaling and time window step back/forward maybe selected using the 20min-8 hour box and the R-axis, C-line and H-Lineboxes.

The Area Alarm Summary Display

This lists up to 100 of the most recent alarms. Twenty of such alarms can belisted on each of five pages of this display. In addition, all units assigned to thestation are represented at the bottom of the screen by targets for calling up theunit alarm summary displays. Alarms may be acknowledged on the top line ofthe screen or the display page.

Time Management

The IAS operates with dual time data. One is the system’s standard time, whichcould be GMT and the other is the ship’s time supplied from the ship’schronometer. The ship’s time is used for alarm summary displays, statuschanges and report print outs. Standard time is applied to trend data and otherprintouts. Use schematic display C-35 to change times as required.

Alarm Management

The IAS initiates alarms from various processes by analogue or digital signalssuch as temperature high, level low, pressure high, etc. It also initiates alarmsfor abnormalities in the integrated automation system itself.

Alarm PrintoutThe historical alarm information is printed out on the alarm printer withreference to time.

The alarm printout provides the time that the alarm occurred, time the alarmwas acknowledged and the time the process recovered from the alarmsituation.

The red printout signifies that the channel/point has gone into alarm; the blackwhen it has returned to normal.

The meaning of the abbreviations is as follows:

RTJ BEGIN Real time journal begin

RTJ END Real time journal end

OFFNORM Digital alarm in alarm state

PVHH Process variable high high alarm

PVHI Process variable high alarm

PVLL Process variable low low alarm

PVLO Process variable low alarm

BAD PV Process variable out of range

The alarm set point is indicated and also the current value on the alarm line.

Fast Alarm Function

The fast alarm function is a high speed scanning function for finding out thecause of any trip. The data is recorded on the hard disk of the history module(HM) automatically. Time resolution is to within 20ms. The operator can printrecorded fast alarms if necessary. Fast alarms selected can be displayed on thescreen and printed in sequence.

Data Logging

The IAS provides a data logging function. It can produce a fixed time report,which is printed out automatically in accordance with a selected time interval.It will also print out a demand report in response to the operator’s request onthe system operation display.

3.2.3 Cargo Part Displays and Operation Planning

In addition to the display of real time data for control and monitoring on theschematic screens, the IAS includes comprehensive operation planning,operation flow, line flow and operation guidance schematics for most normaland out-of-service operations.

Line flow schematics indicate the position of the valves required and the flowsin each line only.

The operation flow mimic schematics are a sequence chart showing the stagesin each operation. Boxes allow access to group control operations and alsomonitoring schematics

The guidance schematics comprise a checklist for the operator. Associatedschematics can be selected and switched to.

Line-ups are a quick reference to indicate the valve settings. Valves can becontrolled via this schematic so that they correspond to the required settingsbefore the operation proceeds. In each case, the colour of the block after settingshould correspond to the colour of the required setting (right hand) block.

3.2.4 Personal Computer Network

The personal computer network interface is composed of a global user station.A Local Area Network (LAN) of 9 PCs are connected to the LAN. Currentdata is updated in the personal computer network interface and stored in thereal time database that can be accessed easily by the PCs which run aHoneywell GDi 3.2 Windows 95 application allowing any monitoring andcontrol schematic display to be set up and viewed within a DOS sub-windowon the PC screen.

No control functions are accessible via the personal computers.



3.2.5 Extension Alarm System

An alarm extension alarm system is provided for the cargo and machinerysystems. All alarms detected by the integrated automation system are sent toselected extension alarm panels located in the officers’ cabins and the publicspaces.

Locations are

Wheelhouse Officers’ recreation roomChief Engineer’s dayroom Crew’s recreation room1st engineer’s dayroom Gymnasium2nd engineer’s dayroom Duty messroom3rd engineer’s dayroom Conference roomGas engineer’s dayroom Swimming poolChief officer’s dayroom Sauna lobby1st officer’s dayroom Lecture roomOfficers’ messroom Health centreCrew’s messroom

All IAS alarms are grouped and the group alarms status is indicated at theextension alarms panels.

Duty Engineer/Officer Selector

A selector on the CACC console is provided for both the cargo and machinerysystems to divert the alarms to the selected duty engineer/officer’s cabin.

For the cargo system,

Gas Engineer

Chief Officer

1st Officer

can be called and the LED indicates the required officer at all Ext AlarmPanels.

If the alarm is not acknowledged at the selected station or the public spacesstation within 60 seconds all stations are alerted.

There is also an Officer Calling switch that alerts all alarm stations.



Issue: 1

No Schematic display title Detail Associated Display

Associated Control / Data Groups

C-1 CARGO SYSTEM OVERVIEW

Piping mimic diagram - shows all valves tanks and pumps in cargo system.

C-2, C-3, C-5, C-6, C-29, C-30

C-2 MANIFOLD (CARGO PIPING)

Piping mimic diagram - shows manifold valves

LIQ ESD VV VAP ESD VV N2 ESD VV

C-3 1/2 C TANK (CARGO PIPING)

Piping mimic diagram - shows all valves in cargo tank No.1 and No.2

C-1, C-10, C-11, C-12, C-13

1/2 C TK S LINE VV EMCY C.P/P DEL VV C.P/P_1(S) AND DEL VV C.P/P_2(P) AND DEL VV C FIL/BRANCH VV 1/2 TK S P/P AND DEL VV 1/2 TK S NOZZLE VV

C-4 3/4 C TANK (CARGO PIPING)

Piping mimic diagram - shows all valves in cargo tank No.3 and No.4

C-1, C-10, C-11, C-12, C-13

3/4 C TK SLINE VV EMCY C.P/P DEL VV C.P/P_3 (S) AND DEL VV C.P/P_4 (P) AND DEL VV C FIL/BRANCH VV 3/4 TK S P/P AND DEL VV 3/4 TK S NOZZLE VV

C-5 MACH ROOM (CARGO PIPING)

Piping mimic diagram C-1, C-10, C-11, C-12, C-13

VAP CONN VV 1/2 VAP CONN VV 2/2 VAP RETURN TO SHORE

C-6 BALLAST SYSTEM OVERVIEW

Piping mimic diagram shows levels, contents in tonnes and drafts

C-1, C-7, C-8, C-9

DRAFT CONDITION

C-7 WATER BALLAST TANK PIPING

Piping mimic diagram – allows valve control

C-6, C-8 FPT/APT SUCT VV LEVEL D WBT SUCT VV LEVEL 1 WBT SUCT VV LEVEL 2 WBT SUCT VV LEVEL 3 WBT SUCT VV LEVEL 4 WBT SUCT VV LEVEL

C-8 WATER BALLAST PUMP PIPING

Piping mimic diagram C-6, C-7, C-9 1 WB PP AUTO START 2 WB PP AUTO START 3 WB PP AUTO START 1 EDUCT VV WB PP CONN VV 1/2

C-9 FIRE BILGE AND WATER SPRAY PUMP PIPING

Piping mimic diagram Control of emergency fire pump, jockey pump, No.1 and 2 fire and GS pumps, water spray pump

C-6, C-7, C-8, C-49

BILGE FIRE PP BILGE CONN VV W SPRAY PP

C-10 HYD/FAN CONTROL Machinery control and monitoring. Control of cargo hydraulic power unit, ballast hydraulic power unit, compressor room fans, electric motor room fans

C-1, C-5, C-6, C-17

C HYD UNIT B HYD UNIT FAN C MR ROOM

C-11 HD COMPRESSOR Machinery control and monitoring control of HD compressors

C-5, C-53, C-70, C-73

VAP CONN VV 1/2 VAP CONN VV 2/2 1 H/D COMP CONT 2 H/D COMP CONT


C-12 B.O/W.U HEATER Machinery control and monitoring Control of boil-off and warm-up heaters Mode selection BO/WU

C-5 VAP CONN VV 1/2 VAP CONN VV 2/2 1 G HTR CONTROL 2 G HTR CONT G HTR CONT HTR DRAIN CONT

C-13 LNG/FORCING VAPORIZER

Machinery control and monitoring Control of LNG and forcing vaporizers Mode selection LNG/FORCING VAP

C-5, C-30 VAP CONN VV 1/2 VAP CONN VV 2/2 VAP DRAIN CONTR M/VAP CONTROL F/VAP CONTROL

C-14 N2 GENERATOR Machinery control and monitoring C-15 IGG UNIT Machinery control and monitoring

Control for IGG plant. Modes selectable via IGG MODE SEL GROUP are purge, IG production, air production

C-1, C-30 IGG VALVE IGG IGG MODE SELECT

C-16 MOTOR-AUX1 Machinery control and monitoring Control indicates operation status and running hours of cargo pumps, stripping/spray pumps HD compressor ballast pumps emergency cargo pump

C-1, C-5, C-17

C-17 MOTOR-AUX2 Machinery control and monitoring Control indicates operation status and running hours of cargo valve hydraulic oil pump main and topping up, ballast engine room valve hydraulic oil pump main and topping up cargo compressor room exhaust fan electric motor room exhaust fan N2 generator compressor fire and GS pumps water spray pump jockey pump glycol water pumps auxiliary CFW pump auxiliary CSW pump emergency fire pump

C-1, C-5, C-6, C-10, C-16

C-18 GAS DETECTION (1) Machinery control and monitoring Control indicates gas levels and alarm status in insulated spaces and vent masts, passageways, forward spaces deck

C-87, C-88

C-19 1TK/BARR SPACE MONITOR

Tank monitoring 6 secondary barrier temperatures 13 cofferdam, trunk deck and duct keel temperatures 4 tank and barrier pressures 2 glycol water temperatures control of tank pressure

C-1, C-20, C-21, C-22, C-29, C-30

PRESS No.1 C Tk

3.2.6 IAS Mimics




C-20 2TK/ BARR SPACE MONITOR

Tank monitoring 6 secondary barrier temperatures 13 cofferdam, trunk deck and duct keel temperatures 4 tank and barrier pressures 2 glycol water temperatures Control of tank pressure

C-1, C-19, C-21, C-22, C-29, C-30

PRESS No.2 C Tk



C-1, C-19, C-20, C-22, C-29, C-30

PRESS No.3 C Tk



C1, C19, C20, C21, C29, C30

PRESS No.4 C Tk

C-23 LOADING MONITOR Operation monitoring - tank levels target levels and calculated volumes vapour flow to shore HD compressor

C-1, C-11 C-36 (index) C-45, C-53

C FILL VV & LEVEL

C-24 UNLOADING MONITOR Operation monitoring - tank levels target levels and calculated volumes tapour flow to shore HD compressor

C-1, C-46, C-55

C PP 1 S AND DEL VV C PP 2 P AND DEL VV

C-25 BALLAST MONITOR Operation monitoring Graphic with H and HH alarms and calculated tank volumes draught and calculated trim (aft – fwd) and list calculated in degrees from draughts and Lpp and beam

C-6, C-7,C-8 C-33 C-36 (index) C-86

C-26 DEBALLAST MONITOR Operation monitoring Graphic with H and HH alarms and calculated tank volumes draught and calculated trim (aft – fwd) and list calculated in degrees from draughts and Lpp and beam

C-6, C-7, C-8 C-33 C-36(index) C-86

C-27 GMS MONITOR Control block schematic for operation monitoring

C-13, C-28, C-41, C-58, C-60

C-28 SPRAYING MONITOR Operation monitoring vapour header and 4 tanks

C-13, C-58, C-60, C-63, C-73

C-29 G.W SYS (HEATING CONTROL)

Operation monitoring Glycol water heaters and pumps enables selection of main and standby lines Temperature control of liquid domes and cofferdams

C-1, C-19 1 GW HTR OUT 2 GW HEATER OUT E GW HEATER C TK CASING TEMP (liq dome) C/D TEMP CONT (cofferdams)

C-30 BARRIER SYSTEM N2PRESS CONTROL

Operation monitoringControl of vacuum pumps

C- 1, C-5 N2 ESD CONT VVN2 BLEED LINE1 N2 GEN2 N2 GENN2 INL PRESS CONTN2 OUTL PRESS CONT

C-31 OPE PLANLOAD/UNLOAD

Operation planning

C-32 OPE PLAN BALLAST Operation planningC-33 OPE PLAN DEBALLAST Operation planningC-34 VV FAIL LIST FOR SEQ Operation planningC-35 SYSTEM OPERATION System operation

Setup of system and ship time, logsfrequency 1-12hour

M-33

C-36 OPE INDEX (OPESELECT)

Operation indexLists of screens for operator planningand guides

C-41 GMS SETPOINT Operation planningSelection of vap pressure headercontrol gauge/absolute

C-42 LINEUP1 (AROUNDTANK)

Line-up screenLists valves required for operationallows control of each from screencolours of actual position shouldcorrespond with required indication

C-19, C-20,C-43

C P/P DEL VVC FILL BRANCH VVS P/P DEL VV1/2 TK S NOZZLE VV3/4 TK S NOZZLE VV

C-43 LINEUP2(LIQ.MAN/HEAD)

Line-up screenLists valves required for operationallows control of each from screencolours of actual position shouldcorrespond with required indication

C-44 LIQ ESD VVSTRIP XOVER VVVAP IN/OUT VVLIQ STRIP HDR VV

C-44 LINEUP3 (VAP LINE) Line-up screenLists valves required for operationallows control of each from screencolours of actual position shouldcorrespond with required indication

C-45, C-46 VAP MANI/XOVER VVCOMP IN OUT VVG/HTR IN/OUT VVVAP IN/OUT VVVAP CONN VVVENT CONN VV

C-45 UNLOADING (OPEFLOW)

Operation flow mimic for unloading C-36 (index)C-42, C-48,C-49, C-50,C-51, C-52,C-53

C-46 LOADING (OPE FLOW) Operation flow mimic for loading C-36 (index)C-42, C-48,C-49, C-50,C-51, C-52,C-53

C-47 GMS (OPE FLOW) Operation flow mimic for GMS C-27,C-36 (index)C-41, C-58,C-60

C-48 LOADING (LINE FLOW) Line flow mimic overview forloading showing required valvepositions

Issue: 1

C-49 OPE. GUIDE(LOAD/UNLOAD1)

Operation guidance checklist forloading and unloading stage 1

C-9, C-10,C-1, C-16C-45, C4-6C-70

LIQX-O/HDR PRESS/TEMP



C-2, C-46,C-62

LIQ ESD VVVAP ESD CONN



C-2, C-45,C-46

1/2 C TKS LINE VVLIQ ESD VVVAP ESD CONN VVBILGE FIRE PP C HYDUNIT

C-52 OPE GUIDE(LOADING1)

Operation guidance checklist forloading stage 1

C-2, C-11,C-45

LIQ ESD VVH/D COMP CONT

C-53 OPE GUIDE(LOADING2)

Operation guidance checklist forloading stage 2

C-11, C-45 C FILL VV AND LEVELH/D COMP CONTVAP RETURN TO SHORE

C-54 UNLOADING(LINEFLOW)

Line flow mimic overview forunloading showing required valvepositions

C-1, C-42,C-43, C-44,C-46

C-55 OPE GUIDE (UNLOAD1) Operation guidance checklist forunloading stage 1For 8-step and 4-step operation

C-24, C-46 1 C TK C P/P AUTO START2 C TK C P/P AUTO START3 C TK C P/P AUTO START4 C TK C P/P AUTO STARTVAP. ESD CONN VV

C-56 OPE GUIDE (UNLOAD2) Operation guidance checklistUnloading stage 2For 8-step and 4-step operation

C-56, C-24,C-59, C-46

VAP. ESD CONN. VVC P/P-1(S) AND DEL VVC P/P-2(P) AND DEL VVC FILL VV AND LEVEL

C-57 OPE GUIDE (LINE C/D) Operation guidance checklist forunloading cooldown for 8-step and4-step operation

C-36 (index)C-59

C FILL/BRANCH VV

C-58 OPE GUIDE (GMS) Operation guidance checklist for GMS C-5, C-47,C-59, C-28

G/HTR1 C TKS LINE COOLDOWNF VAP CONTCOOLDOWN (C.TK)

C-59 S.P/P START GUIDE Operation guidance checklist for spraypump

C-34, C-56,C-57, C-58,C-5

1 SP/P AUTOSTART2 SP/P AUTOSTART3 SP/P AUTOSTART4 SP/P AUTOSTART

C-60 GMS INPUT Operation planning for GMSfor planning ballast and laden voyagevapour pressure curve

C-13, C-27,C-28, C-47,C-58

VPR HDR PRESS CONT

C-61 INERTING P/D (OPE.FLOW)

Operation flow sequence diagram forinerting

C-36 (index)C-42, C-67C-68, C-82

C-62 GASSING UP (OPE.FLOW)

Operation flow sequence diagram forgassing-up

C-36 (index)C-42, C-43,C-44, C-50,C-69, C-70,C-71

C-63 INIT COOLDOWN OPE.FLOW

Operation flow sequence diagram forintial cooldown

C36 (index)C-42, C-43,C-44, C-72,C-73



C-64 WARM UP OPE. FLOW Operating flow sequence diagram forwarm-up

C-36 (index)C-42, C-43,C-44, C-74

C-65 INERTING P/D (OPE.FLOW)

Operation flow sequence diagram forinerting

C-36 (index)C-42, C-43,C-44, C-78,C-79, C-82

C-66 AERATION (OPE.FLOW)

Operation flow sequence diagram foraeration

C-36 (index)C-42, C-43,C-44, C-80,C-81, C-82

C-67 INERT P/D (LINEFLOW)

Line flow mimic for inerting C-1,C-36 (index)C-42, C-43,C-44,

C-68 OPE GUID (INERTINGA/D)

Operation guidance checklist C-1, C-10C-15, C-30,

LOW VOLT HTR FOR C.P/PVENT. VV (VAP TO ATM)C. FILL/BRANCH VV

C-69 GASSING UP (LINEFLOW)

Line flow mimic for gassing up C-1, C-42,C-43, C-44,C-62

C-70 OPE GUID (GASSINGUP1)

Operation guidance checklist forgassing up stage 1

C-1, C-2C-11, C-13C-49, C-62

H/D COMP CONT

C-71 OPE GUID(GASSINGUP2)

Operation guidance checklist forgassing up stage 2

C-11, C-13C-62

M/VAP CONTH/D COMP CONTVAP. MANI/X-OVER VVC. FILL.VV AND LEVEL

C-72 INITCOOLDOWN(LFLOW)

Line flow mimic for initial cooldown C-1, C-42,C-43, C-44,C-63,

C-73 OPE.GUID INITCOOLDOWN

Operation guidance checklist forcooldown

C-11, C-28C-30, C-63

HD COMP CONT1/2 TKS NOZZLE VV3/4 TKS NOZZLE VV

C-74 WARM UP(LINE FLOW) Line flow mimic for warm-up C-1, C-42,C-43, C-44,C-64

C-75 OPE GUID(WARM UP 1) Operation guidance checklist forwarm-up stage 1

C-1, C-10C-16, C-64


C-1, C-19C-64

1 H/D COMP CONT2 G/HTR CONTC TK BTM TEMP


C-1, C-19C-64

1 H/D COMP CONT2 G/HTR CONTC TK BTM TEMP

C-78 INERT B/D(LINE FLOW) Line flow mimic for inerting C-1, C-42,C-43, C-44,C-65

C-79 OPE GUID(INERTINGB/D)

Operation guidance checklist forinerting

C-1, C-30,C-1, C-15,C-65

VENT VV (VAP TO ATM)C. FIL BRANCH VV

C-80 AERATION(LINEFLOW)

Line flow mimic for aeration C-1, C-42,C-43, C-44,C-66

Issue: 1

C-81 OPE GUID (AERATION) Operation guidance checklist for aeration

C-1, C-10, C-15, C-30, C-66

VENT VV (VAP TO ATM) C FILL VV AND LEVEL

C-82 OPE GUID (INERT/AERAT1)

Operation guidance checklist for aeration stage 1

C-2, C-13, C-83

LIQ COOLDOWN VV (2/3) LIQ STRIP HDR VV

C-84 OPE GUID (INERT/AERAT3)

Operation guidance checklist for aeration stage 3

C-3, C-4 C-85

1/2 TANKS NOZZLE VV 3/4 TANKS NOZZLE VV

C-85 BAL. START(GUID) Operation guidance checklist for ballasting. Advises valve line-up

C-64, C-65, C-66

STRIP X-OVER VV VAP. MANI/X OVER VV VAP. CONN. VV COMP IN/OUT VV G/HTR IN/OUT VV

C-86 DEBAL.START(GUID) Operation guidance checklist for deballasting

C-8 BILGE/WATER DET. ALARM

C-87 FRESH W COOLING SYSTEM

Piping mimic diagram. Allows start/stop of cooling water pumps from mimic

C-88 BILGE/WATER DET ALARM

Piping mimic diagram. Indicates alarm status

C-89 GAS DETECTION 2 Machinery control and monitoring control. Indicates gas levels and alarm status in accommodation

C-18, C-88

C-90 GAS DETECTION 3 Machinery control and monitoring control. Indicates gas levels and alarm status in boiler hood and pipe trunk

C-94 REPOSE GROUP SUMMARY

Alarm group summary status



Issue: 1

C36

C47

C45 C31

C46 C31

C61

C62

C63 C31

C42

C43

C44

C32

C33

C64

C65

C66

C48

C54

C23

C24

C25

C26

C57

C67

C69

C72

C74

C78

C80

C41 C60 C27 C28

OPE. INDEX (OPE. SELECT)

OPERATION TO BE SELECTED

NEXT

OPERATION SELECTION

GMS

LOADING

UNLOADING

INERT POST DOCK

GASSING UP

INITIAL COOLDOWN

WARM UP

INERT BEFORE DOCK

AERATION

BALLASTING

DEBALLASTING

LINE COOLDOWN

OPE. FLOW OPE. PLAN LINE UP LINE FLOW OPE. MONITOR OTHERGAS HEATER AND COMPRESSOR START

OPEN INLET AND OUTLET VALVES C05OF SELECTED GAS HEATER.SUCTION AND DISCHARGE VALVESOF SELECTED L/D COMPRESSORAND CHECK THAT VCG873, VCG920 ARE OPEN.

ON GAS HEATER LOCAL PANELSET TCV LOADERTO MANUAL WITH MINIMUM SET POINTAND WARM THROUGH HEATER.

START L/D COMPRESSOR (MACHINERY OP)

FULLY OPEN STEAM TO HEATER AND G121SWITCH TO REMOTE CONTROL WITHSET POINT ADJUSTED TO ABOUT 40OC

NEXT C47

CHIME CAUSE

FORCING VAPORIZER START REQUEST

FORCING VAPORIZER STOP REQUEST

LOW TANK PRESSURE WARNING

OPTIONS : FUEL OIL BACK UPSTART FORC VAPORIZERREDUCE SHAFT SPEED

CHIME RESET

FORCING / COOLDOWN START / STOPSTART OR STOP PUMP C59

SPRAYING

FORCING

MONITORING

COOLDOWN SPRAY HEADER BY ENTERINGSEQUENCE START KEYS FOR EACH TANK

IN TURN : TANKS 1 / 2 G058 TANKS 3 / 4 G059

START OR STOP INTENTIONAL CURVEBY ENTERING SPRAYING SEQUENCE KEY G133

AFTER WARMING THROUGH. FULLY OPENSTEAM TO VAPORIZER AND SWITCH FLOWAND TEMPERATURE CONTROLS TO REMOTE.SET TEMPERATURE CONTROL TO - 40OC G133ENTER CURVE START OR STOP KEY G133

TANK PRESSURE TO BE MONITORED C28

NEXT

C58 OPE. GUIDE (GMS)

C47

Absolute

Absolute

Tank PressureControl Setpoint

Gauge

Gauge

Laden

Manual Auto SprayControl

ToAtmosphere

VentValve

Ballast

DumpMode

To BoilerACC

BoilerGas Flow

Min Gas FlowFrom ForcingVaporzer

ForcingVaporzerSet Point

StopRunSpray

Stand ByTime SchedulePre Set Via C60

+

+

+

Estimated BOG FlowLoaded Voyage

kPa abs.

Tank PressureControl Setpoint

kPa g.

+

PID Automatic SprayControl

Vent Cont.C05C13

PIDPID

Spray ControlMode Auto/Man

Spray PumpRun/Stop

SP/FV ofAbove WorkCont.

Dump/VentMode

Spray NozzleValves

To GasComp.

To F/V SprayHeader

Detail

C28

Detail

C27 GMS Monitor

BallastLaden Cargo Tank Press. ControlDetail G054

OPE. INDEX(OPE. SELECT)

GAS MANAGMENT SYSTEM

GMS (OPE.FLOW)

OPE. GUIDE(GMS)

GMSINPUT

OPE. GUIDE(GMS)

GMS SETPOINT

GMSINPUT

GMS SETPOINT

VAP. HDRPRESSCONT.

C COMPROOM

GMS (OPE.FLOW)

S P/PSTARTGUIDE

SPRAYINGMONITOR

G / HTRI C TKSCOOLDOWN

F VAPCONT.

COOLDOWN(C. TK)

C47

C41

C27NEXT C27

C41

C58

C60

GMS (OPE. FLOW)

LADEN VOYAGE BALLAST VOYAGE

FINISH

FINISH

NOTE: TOTAL BOG CONT. CONDITION TO BE MONITORED

DATA

SHIP MODE : LADEN

BOG CONT. MODE : NON

SHIP MODE :BALLAST


MANOEUVRING

(BOG CONT. MODE : NON)

SET GMS CONT.

SET GMS CONT.

DATA FOR DAY OR NIGHT

WHEN CHIME SOUND.

REFER TO THE DISP. C58

WHEN CHIME SOUND.

REFER TO THE DISP. C58

INTENTIONAL CURVE

START

MANOEUVRING

(BOG CONT. MODE : NONOR DUMP)

GAS BURN STOP

GAS HTR / COMP START


LOADING

UNLOADING

-

-

+



Issue: 1


3.2.7 Use of Ope. Index, Guide and Flow Mimics

The cargo system part of the IAS is configured so that the user is provided withguidance in executing most operations. The IAS has pre-programmed mimicswhich allow the user to:

Select an operation from the Operation Index (Ope. Index Mimic C-36).

Select an Operation Plan (Ope. Plan) from C-36.

Select the Operation Flow (Ope. Flow). This mimic shows inalgorithm form, the sequence of processes within an operation.

Select the Operation Monitor for the operation. This is a mimicwhich shows the process variables, allows control and using thechange zone, allows setpoints to be monitored and varied.

The following explains how the user follows through this process in the controlof the Gas Management System:

a) Select the Operation Index (Ope. Index Mimic C-36).

b) Select the Operation Plan (Ope. Plan) from C36 by touching theC41/C80 items.

c) Select the Operation Flow (Ope. Flow) C-47.

d) Select UNLOADING or LOADING as appropriate (In this example, ballast voyage is used).

e) Touch the SHIP MODE: BALLAST box to initiate the sequence.

f) Follow the sequence, touching the box to select the Ope. Plan.

g) Check through the Ope. Plan C-41 and action accordingly.It is necessary to set GMS control via C-41.

h) If in the Laden mode as in this case, start the gas compressor viaC-58.

i) The intentional curve sets the preprogrammed pressure control via C-60, changes can be made from experience and conditions.

j) The Ope. Guide C-58 is displayed when the chime alerts theoperator.

k) Monitor this sequence throughout by the GMS Monitor C-27 untilthe end of the loaded passage.

The operator uses the change zone boxes to select control group (VAP. HDRPRESS CONT). Exit from the monitor to the Ope. Guid C-58 using the changezone boxes.

l) The operation is terminated by touching the LOADING (finish)box.

m) The laden voyage is less complex and may be operated in thesame way by touching the SHIP MODE: LADEN box.

For cargo operations in-service and out-of-service, line-ups are used. Thesecan be used to check the setting of the valves used in the operation. The line-up screen indicates the valve required and valve actual positions with BLUEopen, WHITE closed. For correct operation both should be set to the samecolour.

! CautionThe correct valve settings are given in the detailed operations in Part 6. Insome cases, particularly for out-of-service operations, valves and otherline devices not controlled via the IAS are used. Also settings may bepartly open, therefore the procedures given in Part 6 should be followedtogether with the sequences from the IAS.


Part 4Cargo and Ballast System

4.1 Cargo Containment System

Introduction

The cargo containment system consists of four insulated cargo tanks, separatedfrom each other by transverse cofferdams, and from the outer hull of the vesselby wing and double bottom ballast tanks.

The containment system serves two purposes:

To contain LNG cargo at cryogenic temperature (-160°C)

To insulate the cargo from the hull structure

The materials used for the hull structure are designed to withstand varyingdegrees of low temperature. At temperatures below their specified limits, thesesteels will crystallise and embrittle. The materials used for the containmentsystem are required to reduce the heat transfer from the hull structure tominimise the boil-off gas from the cargo, as well as to protect the hull structurefrom the effects of cryogenic temperature.

The inner hull is lined with the GTT Mark III integrated tank system,consisting of a thin and flexible membrane, called the primary barrier, whichbears against a supporting insulation structure embodying a secondary barrier.This construction ensures that the entire cargo hydrostatic load is transmittedthrough the membrane and insulation to the hull plating of the vessel.

Membrane or Primary BarrierThe membrane is an assembly of corrugated sheets 1.2 mm thick, made ofAISI304L stainless steel. The sheets, lap-welded together, have two sets oforthogonal corrugations of ogival shape, where the nominal pitch is equal to340mm by 340mm. The corrugations cross each other by means of geometricalsurfaces which are termed knots.

So that the elongation of the sheets in the two directions of the corrugationswill be the same for the same applied load, it is necessary to give differentdimensions to the corrugations of the two sets. Consequently there is one setof large corrugations, parallel to each other, and one set of small corrugations,also parallel to each other but at right-angles to the first set. Each sheet isformed on an automatic folding machine using special tools.

On each of the tank walls, the corrugations present a pattern of squares, witheach set of corrugations being parallel to one of the axes of the vessel.

Along the edges of the tank the joining of the corrugations on two adjacentwalls takes place by means of angle pieces, each one formed by foldingcorrugation into a specially designed knot.

The sheets are fixed to the supporting insulation along half their perimeter bywelding onto small stainless steel blocks solidly fixed in the insulationstructure. This anchoring has three purposes; it takes up the unbalanced forces

set up by non-uniform or transient temperature conditions, it supports theweight of the sheets on the vertical walls and roof of the tank and it allows asmall vacuum in the tank. The half perimeter is overlapped by, and lap-weldedto, the adjacent sheet. Along the edges and corners of the tank, the sheets areanchored to rigid stainless steel corner pieces, and the corners in turn aresecured onto the insulation by hardwood keys.

The welding process is Tungsten Inert Gas (TIG) without filler metal.

Insulation and Secondary BarrierThe insulation and secondary barrier assembly is composed of the followingelements, as shown in illustration 1.3.2a

Level wedges, fixed to the inner hull and forming a rectangular pattern, serveas a support for the insulation panels bonded to them. The plywood panels ofthe insulation barrier are secured to the inner hull by studs. The level wedgethickness is individually calculated to take into account any slight irregulari-ties in the inner hull surface.

Insulating sandwich panels, composed of an outer plywood face, onto which isbonded the membrane sheets and two layers of insulating foam, form the actualinterbarrier and insulation space barrier. Between the IBS and IS foam layersthere is a triplex membrane (scab) bonded onto the IS foam and forms theimpervious barrier to the nitrogen circulation.

The insulating sandwich panels are assembled by bonding with polyurethaneor epoxy glue. Insulation continuity between the panels is assured byglasswool (flat joint) which are sandwiched between PVC films. Tightness andcontinuity of the secondary barrier is achieved by means of a bonded scab-splice made of prefabricated riged polyurethane foam with reinforcing glassfibres.

For the corners of the tank, the sandwich panels are cut and assembled to formdihedral and trihedral corners, the joints between the panels of these cornersbeing formed of pre-compressed expanded PVC.

The insulation dimensions have been determined to ensure that:

The heat flow into the tank is limited to such an extent that theevaporation, or boil-off rate, is about 0.15% per day.

The inner hull steel does not attain a temperature below itsminimum design value, even in the case of failure of the primarybarrier.

Any deflections resulting from applied strains and stresses are acceptable bythe primary barrier.

In addition to these requirements, the insulation acts as a barrier to prevent anycontact between ballast water and the primary barrier, in the event of leakagethrough the inner hull.

The insulation system is designed to maintain the boil-off losses from the cargoat an acceptable level, and to protect the inner hull steel from the effect ofexcessively low temperature. If the insulation efficiency should deteriorate forany reason, the effect may be a lowering of the inner hull steel temperature, iea cold spot and an increase in boil-off from the affected tank. Increased boil-off is of no direct consequence to the safety of the vessel, as any excess gasmay be vented to atmosphere via the forward riser at No.1 tank. The inner hullsteel temperature must, however, be maintained within acceptable limits toprevent possible brittle fracture.

Thermocouples are distributed over the surface of the inner hull, but unless acold spot occurs immediately adjacent to a sensor, these can only serve as ageneral indication of steel temperature. To date, the only sure way of detectingcold spots is by frequent visual inspection of the ballast spaces on the loadedvoyage. (See Section 5.1.)

The grade of steel required for the inner hull of the vessel is governed by theminimum temperature this steel will reach at minimum ambient temperatureand assuming the primary barrier, the stainless steel membrane, has failed, sothat the LNG is in contact with the secondary barrier.

In addition to failure of the membrane, local cold spots can occur due to failureof the insulation.

While the inner hull steel quality has been chosen to withstand the minimumtemperature likely to occur in service, prolonged operation at steel tempera-tures below 0°C will cause ice build-up on the plating, which in turn will causea further lowering of steel temperature due to the insulating effect of the ice.To avoid this, glycol heating coils are fitted in each cofferdam space, ofsufficient capacity to maintain the inner hull steel temperature at 5°C under theworst conditions.

If a cold spot is detected either by the inner hull temperature measurementsystem, or by visual inspection, the extent and location of the ice formationshould be recorded. Small local cold spots are not critical, and provided a closewatch and record are kept as a check against further deterioration andspreading of the ice formation, no immediate action is required. If the cold spotis extensive, or tending to spread rapidly, flooding of the ballast space shouldbe carried out. The thermal capacity of the water, plus the improved heattransfer from outside, should maintain the steel temperature at, or near, theambient sea water temperature. In the unlikely event that this remedy is insuf-ficient and it is considered unsafe to delay discharge of cargo until arrival atthe discharge port, the final recourse will be to jettison the cargo via a portablenozzle fitted to one of the midships liquid manifolds, using a single main cargopump.

Issue: 1 4.1 Cargo Containment System Page 1 of 1


Issue: 1 4.2 Cargo Piping System Page 1 of 4

Key

Illustration 4.2a Cargo Piping System

LNG Liquid

LNG Vapour

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

1

2

1

LD Compressor No.2(Inboard)

Boil Off/Warm UpHeaters

LNGVaporizer

Demister

ForcingVaporizer

HD Compressor No.2(Inboard)

HD Compressor No.1(Outboard)

LD Compressor No.1(Outboard)

Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1

From Inert Gas/Dry Air Plant

For Inerting CargoMachinery Room

To Engine RoomFuel Gas Burning

FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100

CS751

CS250

CS208CS207

CS251

CS252

CS255

CS254CS256

CL200CL203

CS150

CS151CS152

CG770

CS155

CS154CS156

CL110

CL700

CL103

CS058

CS068

CS056

CS066CS768

CS766

CS762

CS764

CS054

CS064

CS052

CS062

CS750

CS057

CS067

CS065

CS055

CS053

CS063

CS061

CS051

CS761

CS763

CS765CS767

CS754

CS753

CL303

CS350

CS351

CS352

CL308CL307

CS354CS356

CS355

CS752

CG876

CG872

CG875

CG913

CG904

CG901

CG922

CG918

CS951

CS902

CS901

CG906

CG903

CG921

CG914

CG916

CG919

CS952

CS903

CS904

CS450

CL403

CS451

CS452CS455

CS456

002

056

CL201CL202

CL101CL102

CL302CL301

CL402

CS454CL401

CG079

CL042

CL044CL034

CL022CG072

CG078

CL032

CL012

CL024 CL014

CG900

CG920CG915 CG910

CG912

CG909

CG907

CL041CL031

CG071

CG077

CL021CL011

CL013CL023

CL033CL043

CG873

CG874


4.2 Cargo Piping System

Description

The cargo piping system is illustrated in a simplified perspective drawingshowing only the principal features of the system.

Liquid cargo is loaded and discharged via the two crossover lines at midshipsand is delivered to and from each cargo tank liquid dome via the main liquidline which runs fore and aft along the trunk deck. Each crossover line atmidships separates into two loading/discharging connections, port andstarboard, making a total of four loading/discharge connections on each side ofthe ship.

The cargo tank vapour domes are maintained in communication with eachother by the vapour main running fore and aft along the trunk deck. The vapourmain also has a cross connection at the midship manifold for use in regulatingtank pressures when loading and discharging.

When loading, the vapour main and crossover, together with the HDcompressors are used to return the displaced gas from the tanks back to theshore installation. When discharging, the vapour main is used in conjunctionwith either the vapour crossover, or a vaporizer, to supply gas to the tanks toreplace the outgoing liquid cargo.

The stripping/spray line can be connected to the liquid crossover lines and canbe used to drain or to cool down each cargo tank, and also to spray duringdischarging if the return vapour is insufficient. The spray line on each tankconsists of two spray assemblies inside the tank at the top to distribute theincoming liquid into several spray nozzles in order to assist in evaporation andthus achieve a better cooldown rate.

The vapour main lines are connected to the vapour dome of each tank. Thevapour domes also house the N2 exhaust control valves for the IBS and ISbarriers, which also includes a set of relief valves from the IBS and IS spaces.Additionally there are pressure pick up and three sample points.

The stripping/spray, liquid line and vapour mains have branches to and fromthe cargo machinery room with connections to the compressors, heaters andvaporizer for various auxiliary functions. Removable bends are supplied forfitting where necessary to allow cross-connection between the variouspipework for infrequent uses such as preparing for dry dock and recommis-sioning after dry dock.

The vapour main connects the gas domes to each other for the venting of boiloff gas, which discharges to atmosphere through vent mast riser No.1. Thevapour main also directs the boil-off cargo vapour to the engine room for gasburning, via the LD compressors and boil-off gas heaters.

The Inert Gas and Dry-Air System (section 4.10), located in the engine room,is used to supply inert gas or dry-air to the cargo tanks via piping whichconnects with the main cargo system through a double non-return valve toavoid gas returning to the engine room.

All of the cargo piping is welded to reduce the possibility of joint leakage.Flanged connections are electrically bonded by means of straps providedbetween flanges to ensure that differences in potential due to static electricitybetween cargo and other deck piping, tanks, valves and other equipment areavoided.

Both liquid and vapour systems have been designed in such a way thatexpansion and contraction are absorbed in the piping configuration. This isdone by means of expansion loops and bellows on the liquid and vapour pipingrespectively.

Fixed and sliding pipe supports and guides are provided to ensure that pipestresses are kept within acceptable limits.

All sections of liquid piping that can be isolated, and thus possibly trappingliquid between closed valves, are provided with safety valves which relieveexcess pressure to the nearest vapour dome. This is a safety measure, althoughnormal working practice is to allow any remaining liquid to warm up and boiloff before closing any such valves.

All major valves such as the midships manifold (port and starboard) valves,also called ESDS manifold valves, individual tank loading and dischargevalves and the BOG valve to the engine room are remotely power operatedfrom the cargo console, so that all normal cargo operations can be carried outfrom the Centralised Administration and Control Centre (CACC).

When an ESDS is activated, the closing of the manifold valves is effected, thusdiscontinuing loading or unloading operations.

A non-return valve is fitted at the discharge flange of each cargo pump. A 5mmhole is drilled in the valve disc to allow the tank discharge lines to drain downand be gas freed. Non-return valves are also fitted at the discharge flange of thecompressors. The spray/stripping and emergency cargo pump discharge lineshave non-return valves sighted directly after the hydraulically operateddischarge valves.

A small 6mm diameter spray nozzle is also fitted at the top of each cargo pumpdischarge line inside the tank to cool down the auxiliary pump tower leg inorder to maintain a cold temperature throughout the complete discharge.

(Note ! Electrical bonding by means of straps is provided between boltedflanges. Whenever a section of pipe or piece of equipment is unbolted, thebonding straps MUST be replaced when the flanged joint is remade.)

4.2.1 Liquid LineThe system comprises a 650/450mm butt welded cryogenic stainless steelpipeline connecting each of the four cargo tanks to the loading/dischargemanifolds at the ship side by means of a common line.

At each tank liquid dome there is a manifold which connects to the loading anddischarge lines from the tank to allow for the loading and discharge of cargo.

This manifold on the liquid dome connects to the tank discharge lines from theport and starboard cargo pumps, the loading line, emergency pump well andspray line.

No.2 and No.3 tanks have the facility to fill the discharge line prior to startingthe cargo pumps in order to prevent pressure surge.

At certain points along the liquid line, blank flanges and sample points arefitted to facilitate inerting and aeration of the system during refit.

All sections of the liquid line outside the cargo tanks are insulated with a rigidpolyurethane foam covered with a moulded GRP cover to act as a tough waterand vapour tight barrier.

4.2.2 Vapour Line

The system comprises a 500/400mm flanged cryogenic stainless steel pipelineconnecting each of the four cargo tanks by means of a common line to theshipside vapour manifold, the compressor house and the forward vent mast.

The line to the compressor house allows for the gas vapour to be used in thefollowing manner:

Sent ashore during cargo loading by means of the HD compressors in order tocontrol pressure in the cargo tanks.

During ballast/loaded voyages the boil-off gas is sent to the engine room viathe LD compressors and heater for use as fuel in the boilers.

During repair periods the gas to be vaporized and used to purge-dry the cargotanks.

The line to the forward vent mast acts as a safety valve to all tanks and is usedto control the tank pressure during normal operations.

At certain points along the vapour line, blank flanges and sample points arefitted to facilitate inerting and aeration of system during refit.

All sections of the vapour line outside the cargo tanks are insulated with a rigidpolyurethane foam covered with a moulded GRP cover to act as a tough waterand vapour tight barrier.




Key

Illustration 4.2a Cargo Piping System

LNG Liquid

LNG Vapour

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100

CS751

CS250

CS208CS207

CS251

CS252

CS255

CS254CS256

CL200CL203

CS150

CS151CS152

CG770

CS155

CS154CS156

CL110

CL700

CL103

CS058

CS068

CS056

CS066CS768

CS766

CS762

CS764

CS054

CS064

CS052

CS062

CS750

CS057

CS067

CS065

CS055

CS053

CS063

CS061

CS051

CS761

CS763

CS765CS767

CS754

CS753

CL303

CS350

CS351

CS352

CL308CL307

CS354CS356

CS355

CS752

CG876

CG872

CG875

CG913

CG904

CG901

CG922

CG918

CS951

CS902

CS901

CG906

CG903

CG921

CG914

CG916

CG919

CS952

CS903

CS904

CS450

CL403

CS451

CS452CS455

CS456

002

056

CL201CL202

CL101CL102

CL302CL301

CL402

CS454CL401

CG079

CL042

CL044CL034

CL022CG072

CG078

CL032

CL012

CL024 CL014

CG900

CG920CG915 CG910

CG912

CG909

CG907

CL041CL031

CG071

CG077

CL021CL011

CL013CL023

CL033CL043

CG873

CG874


4.2.3 Spray Line

The system comprises a 65mm butt welded cryogenic stainless steel pipelineconnecting the spray pump in each of the four cargo tanks to the spray mainline and serves the following functions by supplying liquid gas to:

Spray rails in each tank, used for tank cooldown and gas generationMain liquid line, used for cooling down lines prior to cargo operationsPriming of discharge lines in No.2 and No.3 cargo tanks to prevent linesurge when starting main cargo pumpsSupply of liquid to vaporizers for gas generation to compressors and heaters

At certain points along the spray line, blank flanges and sample points arefitted to facilitate the inerting and aeration of the system during refit.

All sections of the spray line outside the cargo tanks are insulated with a rigidpolyurethane foam covered with a moulded GRP cover to act as a tough waterand vapour tight barrier.

4.2.4 Emergency Vent Line (One Tank Operation)

The system comprises a 300mm flanged pipeline which can be connected tothe vapour line and the forward riser for use when ‘One Tank Operation’ isrequired.

The use of this line enables a single tank to be isolated and repair work carriedout without having to warm up and inert the whole vessel.

Connection to each individual tank is by means of a portable flexible hosebetween the 300mm blank flanges situated at each vapour dome on the vapourand emergency vent lines.

Connection to the forward vent mast line is by means of a portable elbow bend.

During single tank operations it is possible to connect to the inert gas/dry airplant by means of a portable elbow bend.

In the unlikely event of a cargo spill into the ballast tanks, it is possible toconnect the inert gas/dry air plant via the emergency vent line to the ballastsystem using flexible hoses and purge the ballast tank.

At certain points along the emergency vent line, blank flanges and samplepoints are fitted to facilitate the inerting and aeration of the system during refit.

4.2.5 Fuel Gas Line

During transportation of LNG at sea, gas vapour is produced due to the transferof heat from the outside sea and air, through the tank insulation. Also energyis absorbed from the cargo motion due to the vessel’s movement.

Under normal power conditions, the boil-off gas is used as a means of fuel inthe ship’s boilers.

The gas vapour is taken from the main vapour line and is passed through themist separator then on into the LD compressors. It then passes through the boil-off/warm-up heater before going to the ship’s boilers where it is burnt as fuel.

4.2.6 Vent Line

During normal operations the pressure in the tanks is controlled by the use ofthe boil-off gas in the boilers as fuel, or controlled via the forward vent mastand the common vapour line.

Each cargo tank is also fitted with an independent means of venting. Thiscomprises of two 250mm lines exiting the tank top into their own pilotoperated relief valve. From here the gas passes through a 400mm line into avent stack where it is vented to atmosphere.

All vent stacks are protected by a nitrogen purge fire smothering system.

At certain points along the vent line, sample points are fitted to facilitate theinerting and aeration of the system during refit.

Sections of the vent line outside the cargo tanks are insulated with a rigidpolyurethane foam covered with a moulded GRP cover to act as a tough waterand vapour tight barrier.

4.2.7 Inerting/Aeration Line

The system comprises of a 450mm flanged line which supplies inert gas/dry airto the cargo tanks and pipelines for inerting and drying during refit periods.

The inert gas/dry air is supplied from the inert gas plant situated in the engineroom.

The line is connected to the emergency vent line and the liquid line by meansof portable elbow bends.

By selective use of the bends and flexible hoses it is possible to inert/aerate allor a single cargo tank.

The cargo machinery room can also be flooded with inert gas/air by swingingthe spectacle flange on the line leading to this space.



Issue: 1 4.3 Cargo Pumps Page 1 of 10

Pump Characteristic CurveMain Cargo Pump

Representative Motor Performance Data (Calculated)522.2kW / 3 phase / 440V / 60Hz / Y5000

1800

1799

1798

1797

1796

1795

1794

1793

1792

1791

1790

1789

1100

1000

900

800

700

600

500

400

300

200

100

0

110

100

90

80

70

60

50

40

30

20

10

0 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700

Shaft Power Output (kW)

Efficiency (%)

Power Factor (%)

Speed (RPM)Current (Amperes)

KW Input (kW)

Flow (m3/h)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 22000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0

50

100

150

200

250

300

350

400

450

500

0

25

50

75

100

125

150

175

200

225

250

0

10

20

30

40

50

60

70

80

90

100

Liquid: LNGSpecific Gravity: 0.500Rated Flow: 1,700 m3/hRated Head: 155 metresImpeller Dia: 628 mm

Total HeadShaft Power at 0.50 SP GR (kW)

Efficiency

Pumpdown

NPSHR

Min

imum

Con

t. F

low

Max

imum

Flo

w

Speed(rpm)

kW Input (kW) andCurrent (Amperes)

Efficiency andPower Factor (%)

Efficiency(%)

NPSH andPumpdown (m)

Shaft Power(kW)

Head(m)

Electrical Cable

Lifting Eyebolt

Pump Discharge

Junction BoxCooling/Lubricating Filter

Stator

Rotor

Impeller

Automatic ThrustBalancing Device

Pump Inlet

Lower Bearing

Upper Bearing

Illustration 4.3.1a Main Cargo Pumps


4.3 Cargo Pumps

General Description

The ship is fitted with submerged, electric, single-stage (the stripping/spraypumps are two-stage), centrifugal cargo pumps manufactured by EbaraCryodynamics. They are installed at the bottom of each tank.

Two sizes of pump, main cargo and stripping/spray pumps are installed as fixedunits, i.e. two main cargo pumps and one stripping/spray pump per tank.

In addition, provision is made at each tank to introduce an auxiliary emergencycargo pump in case of total cargo pump failure. One emergency pump is carriedon each ship.

Operation

The cargo pumps are started and stopped from the CACC via IAS mimics. Thecontrol is obtained through the different mimics where the cargo pumps arepresent. They will also be automatically stopped in the event of variousshutdown trips being activated both in relation to the cargo system and thepumps themselves.

Each cargo pump electric motor is protected from:

Thermal overload (overcurrent)

Under-current (no load operation)

Imbalance between phases (single-phasing)

Too long starting

Under normal circumstances, the cargo pumps are started directly on-line.Under emergency conditions there is a facility to connect either of the cargopumps to the emergency switchboard via the soft starting control, which islocated between the cargo switchboard rooms on U deck. Only one pump at atime can be connected in this manner, via portable flexible cables.

The power supply to the cargo pump motors is made available via cargo switch-boards which are arranged in two independent sections that are normallyoperated as coupled via a bus-tie connection or independently. No.1 cargoswitchboard supplies the starboard pumps in all four tanks, while No.2 cargoswitchboard supplies the port cargo pumps.

Each of the cargo switchboards can be supplied by either or both of the mainswitchboards.

Due to high electrical load imposed on the cargo switchboards by the runningof main cargo pumps, there is a limitation on the number of pumps that can berun depending on the electrical power availability, i.e.:

Eight main cargo pumps when at least two generators are in parallel

Four main cargo pumps when only one generator is in use and or bothcargo switchboards are coupled

The pumps should be started individually and sequentially, as required, withthe pump discharge valve open (approximately 15%). The minimum level atwhich the main cargo pumps can pump is 300mm at even keel, whichrepresents a total of 206 m3 in tank No.1, 372 m3 in tank No.2, 372 m3 in tankNo.3 and 328 m3 in tank No.4.

4.3.1 Main Cargo Pumps(See illustration 4.3.1a)

Specification

Manufacturer: Ebara International CorporationPump model: 12EC-24No. of stages: 1Operating temperature: -163°CCapacity rated flow: 1,700 m3/hRated head: 155 mPower rated: 465 kWEfficiency: 77.1 %Rotational speed: 1,780 rpm

Each main cargo pump is rated to discharge 1,700 m3/h at 155 metres head ofLNG. For optimum discharge results, bulk discharge will be carried out with 8pumps running in parallel.

The pump discharge valves will be throttled to ensure optimum performance asindicated by the pump performance graph.

During the course of discharge, changes in flow rate and tank levels will alterthese readings and the discharge valve will have to be re-adjusted accordingly.

Under normal conditions it should be possible to maintain full discharge rateuntil the tank level approaches approximately 0.7 metres at which time thepump will start to cavitate and lose suction as indicated by fluctuations in thedischarge pressure and ammeter readings.

The discharge valves should be throttled to stabilise conditions and one pumpstopped if necessary. The remaining pump is progressively throttled in tomaintain suction and to prevent operation of the low discharge pressure trip,until a level of 0.3 m is reached. This is the unpumpable level at even keel.

By trimming the vessel 1 m or more by the stern, it should be possible to reducethe amount of liquid remaining in the tanks before the pumps are stopped.Adjust the trim carefully at the end of discharging cargo to give an even keelfor gauging.

The cargo pumps may be run in closed circuit on their own tanks by openingthe loading valve. This may be required if the discharge is temporarily haltedwhen the tanks are at low level, thereby avoiding the problems of restartingwith low level and low discharge pressure.

The pumps must not be started if the tank level is 1 m or below. If the pumpshave to be restarted after a shut down, then a period of not less than 5 minutesmust have elapsed. A further 15 minutes must have elapsed before eachsubsequent restart can take place, with a maximum number of 4 restartsallowed per hour.

The cargo pumps will be automatically stopped should any of the followingoccur:

Cargo tank pressure below or equal to IBS pressure plus 0.5kPa(ESDS)

Vapour header pressure below or equal to atmospheric pressureplus 0.3kPa

Extreme high level in cargo tank (99% volume)

Activation of emergency shut down trip(10 pushbuttons and 11 fusible elements) (ESDS)

Activation of ship/shore pneumatic, fibre-optic or electrical shut-down (ESDS)

Motor single-phasing

Low motor current

High motor current (electrical overload)

Low discharge pressure with time delay at starting

CACC emergency stop

ESDS signifies that all cargo plant is shut down in addition to the pump(s) onthe tank(s) in question.

(Note ! An insulation test of all pumps is to be carried out after leaving theloading port in order to establish that all pumps are operational and to allowtime for the installation of the emergency cargo pump should it be necessary.)




Start

Seq Start/StopSwitch = 'Start'

Operation Mode isSelected

Own Cargo Pumpis Running

Another Pump in SameTank is Running


8 Step or 4 Step

8 Step or 4 Step

Another Cargo PumpStart Function in

Same Tank is Running

Seq Start/StopSwitch Stop


Seq AbnormalStop Processing


8 Step or 4 Step

8 Step or 4 Step

Pump Stop

Seq AbnormalStop Processing

Full Open Filling Valve

Load Controller Mode : Auto

Activate Chime (10 sec)


Run Pump

Wait (5 sec)

Wait (60 sec)

Stop Pump

Set Pre-Set Value of CargoPump Discharge ValvePosition To Controller

Pre-Set Value of PumpLoad to Pump

Load Controller

Discharge valve PositionController Mode : CAS

Load ControllerMode : Manual

Reduce PositionDischarge Valve

Full CloseDischarge Valve

Cargo Pump Start Functionis Completed

Discharge Start OperationFinish Check

Filling Valve Position < 2%and

Liquid Branch Valve Position > 50%

Stop Level > LO*2

Tank Level < LO*2 + α1*4Tank Level <

Stop Level + α2*5


8 Step or 4 Step

8 Step or 4 Step


Discharge Start ConditionCheck Filling Valve Position > 95%

andLiquid Branch Valve Position < 2%

FullOpen

FullClose

LiquidBranchValve

FillValve

Discharge Operation Start

Time (sec)

Time (sec)

FullOpen

FullClose

20 sec 40 sec

60 sec

Illustration 4.3.1b Unloading Flow Diagram


Following cooldown after the cargo tanks have been inerted, it is mostimportant that the cargo pumps are fully submerged in liquid LNG and remainin that condition for 1 hour. This is in order that thermal stabilisation can takeplace. Only after this point can the pumps be started. Failure to do so mayresult in severe damage to the pump.

Caution !The cargo pumps must not be started or operated against a closeddischarge valve, due to potential insufficient cooling, lubrication andexcessive vibration.

Caution !The cargo pumps must only be operated between the minimumcontinuous capacity (562m3/h) and maximum capacity (2,040m3/h).

Caution !If there is a situation of a sustained rotor lock during starting, then arestart may only be initiated after a period of 30 minutes has elapsed witha total two restarts allowed under this condition.

Procedure for Starting the Main Cargo Pumps

The IAS system guides the operator through the operational steps to bring themain cargo pumps on line for discharging cargo.

a) Select schematic display C-36, this will allow the operator toselect UNLOADING from the Operation Selection.

b) Schematic C-46 OPE. FLOW should now be selected. Thisschematic should be followed, working through the various subareas.

c) Select the cargo mimic display C-31OPE. PLAN. This will allowthe operator to make the selection for the manifold to be used andalso the data selection for AUTO. OPE Unload. The relevant datafor pump(s), stop levels and motor loads can be input.

d) Schematic C-54 LINE FLOW should now be selected for theopening of the requisite valves and starting of the pumps.

e) Open the discharge valve 18-20% (maximum). If the valveposition does not correspond to the request, a time-out (valvefailed) alarm is displayed. The valve will change to the lineprocess colour when the request condition is met.

f) Choose the pump symbol for starting the pump. The followinginformation appears on the lower side of the screen in the ChangeZone.

Start the associated main cargo pump. The IAS goes through a sequence oflogic events to verify conditions, see illustration 4.3.1b.

Once the pump has started (the pump symbol changes from white stop to rungreen) open the discharge valve gradually from the operator station via theincremental button to give the required flow rate.

The discharge pressure and pump motor amps are monitored and adjusted toensure the most efficient operation as indicated on the pump performancegraph, with due regard being taken of the head of liquid on the pump dischargeflange.

The manifold on/off valves are controlled from the mimic screen, the positionstatus of which are indicated by limit switches.

(Note ! The number of starts on the main cargo pump is limited to four startsper hour.)




Pump Characteristic CurveStripping/Spray Pump

Representative Motor Performance Data (Calculated)22.4 kW / 3 phase / 440V / 60Hz / Y250

100

90

80

70

60

50

40

30

20

10

0

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

40

36

32

28

24

20

16

12

8

4

0

200

180

160

140

120

100

80

60

40

20

0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Liquid: LNGSpecific Gravity: 0.500Rated Flow: 50 m3/hRated Head: 145 metresImpeller Dia: 214 mm

Flow (m3/h)

Total Head

Efficiency

Pumpdown

NPSHR

Shaft Power at 0.50 SP GR (kW)

Min

imum

Con

t. F

low

Max

imum

Flo

w

3600

3590

3580

3570

3560

3550

3540

3530

3520

3510

0

100

90

80

70

60

50

40

30

20

10

0 0 5 10 15 20 25 30


Speed (rpm) Efficiency (%)

Power Factor (%)

kW Input (kW)Current (Amperes)

kW Input (kW), Current (Amperes)Efficiency and Power Factor (%) Speed (rpm)

Efficiency (%)NPSH andPumpdown (m)

Shaft Power(kW)

Head(m)

Electrical Cable

Lifting Eyebolt Pump Discharge

Junction Box

Cooling/Lubricating Filter

Rotor

Stator

Upper Impeller

Automatic ThrustBalancing Device

Lower Impeller

Pump Inlet

Inlet Filter

Lower Bearing

Upper Bearing

Lifting Eyebolt

Illustration4.3.2a Stripping/Spray Pumps


4.3.2 Stripping/Spray Pumps(See Illustration 4.3.2a)

Specification

Manufacturer: Ebara International CorporationPump model: 2EC-092No. of stages: 2Operating temperature: -163°CCapacity rated flow: 50 m3/hRated head: 145 mPower rated: 18 kWEfficiency: 54.7%Rotational speed: 3,560 rpm

A stripping/spray pump is installed in each tank for cooling purposes and forforced vaporization of LNG. It is rated at 50 m3/h at 145 metres head of LNG.

The pumps are started and stopped from the CACC via the IAS. In anemergency all pumps will be stopped by activation of an ESDS trip.

The instances when these pumps can be used are:

To cool down the main liquid lines prior to discharging

To cool the tank membranes and insulation during ballast voyageprior to arrival at loading terminal by discharging LNG to thespray header in the tanks

To pump LNG from the tanks to the forcing vaporizer whenforced vaporization of LNG in the boilers is required

To enable each cargo tank to be stripped as dry as possible forreasons such as technical stop involving cargo tank entry

Whenever possible the stripping/spray pump should be started early enough toavoid possible starting problems due to very low tank levels (about 0.5 mminimum). The spray pumps should not be started at a level below 0.25 m,with an unpumpable level at even keel of 0.15 m.

The pumps must not be started if the tank level is 0.25 m or below. If the pumpshave to be restarted after a shutdown, then a period of not less than 5 minutesmust have elapsed. A further 15 minutes must have elapsed before eachsubsequent restart can take place, with a maximum number of four restartsallowed per hour.

Following cooldown after cargo tanks have been inerted, it is most importantthat the cargo pumps are fully submerged in liquid LNG and remain in thatcondition for one hour. This is in order that thermal stabilisation can take place.Only after this point can the pumps be started. Failure to do so may result insevere damage to the pump.

Caution !The spray pumps must not be started or operated against a closeddischarge valve, due to potential insufficient cooling, lubrication andexcessive vibration.

Caution !The spray pumps must only be operated between the minimumcontinuous capacity (16.4 m3/h) and maximum capacity (59.6m m3h).


The stripping/spray pumps will be stopped automatically should any of thefollowing occur:

Cargo tank pressure below or equal to IBS space pressure plus0.5kPa (ESDS)

Vapour header pressure below or equal to atmospheric pressureplus 0.3kPa (ESDS)

Extreme high level in cargo tank (99% volume)

Activation of ESDS trip: (10 pushbuttons, and 11 fusible elements) (ESDS)

Activation of ship/shore pneumatic, fibre-optic or electricalshutdown (ESDS)

Motor single-phasing

Low motor current

High motor current (electrical overload)

Low discharge pressure with time delay at starting

CACC emergency stop


Procedure for Starting the Stripping/Spray Pumps

The IAS system guides the operator through the operational steps to bring themain cargo pumps on line for discharging cargo.

a) Select schematic display C-59, this will allow the operator tofollow the Spray/Stripping Pump Start Guide. The start guideallows the operator to select the process function, i.e. ArmCooldown, Line Cooldown or GMS as well pump selection andvalve operation via the relevant sub schematic mimics.

e) Open the discharge valve 15% (maximum). If the valve positiondoes not correspond to the request, a time-out (valve failed) alarmis displayed. The valve will change to the line process colourwhen the request has been met.

Start the associated stripping/spray pump. The IAS goes through a sequence oflogic events to verify conditions, see illustration 4.3.2b and c.

Once the pump has started (the pump symbol changes from white stop to rungreen) open the discharge valve gradually from the operator station via theincremental button to give the required flow rate.

The discharge pressure and pump motor amps are monitored and adjusted toensure the most efficient operation as indicated on the pump performancegraph, with due regard being taken of the head of liquid on the pump dischargeflange.

(Note ! The number of starts on the main cargo pump is limited to four startsper hour, with a starting duration of 1.2 seconds for each pump.)




Start4.3.2b Spray Start Sequence

No

No

Mode : P-Auto

Mode : P-Auto

Yes

Yes

End


Spray Cool DownSeq is Running


Run Pump

Wait (5 sec)

Start Control *1

*1 Discharge Valve Position Controller Mode : CAS

Return Valve Position Controller Mode : CAS

Spray Pump Load Controller Mode : CAS

*1 Discharge Valve Position Controller Mode : AUTO

Spray Header Pressure Controller Mode : AUTO

Pre-Set PositionDischarge Valve

Full OpenSpray Master Valve

and Spray Return Valve

Set Pre-Set Value ofspray Nozzle Inlet Press

to Controller

Set Pre-Set Value OfPump Load to

Pump Load Controller




Start

4.3.2c Spraying Control Start Sequence

No

No

No

No

No

No

No

No

No.1 No.2

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

End


Laden / BallastMode is Ballast

Operation Mode isSelected

Intentional Curve ControlSeq is Running

Spray Nozzle ValveNo.1 or No. 2 Select

Tank Press. > Upper Limit *1

Seq Start/StopSwitch Start

Start Intentional CurveControl

Close No. m Spray NozzleValve All Tank

Open No. m Spray NozzleValve All Tank

Open No. m Spray NozzleValve All Tank

Close No. m Spray Nozzle

Valve Most Cooled Tank

Open No. m Spray Nozzle ValveCargo Tank Temp (50%)

Max Tank

Selected No.1m = 1

Selected No. 2m = 2

Tank Press. < Lower Limit *2

Cargo Tank Temp (50%)Check T > max *3

Cargo Tank Temp (50%)Check T < T max *3

*3

*1 Upper Limit = Value of Intentional Curve + 1 (kPa)

*2 Lower Limit = Value of Intentional Curve - 1 (kPa)

*3 T = Cargo Tank Temperature (50%) Max - Cargo Tank Temperature (50%) Min

T max : Differential MAXT min : Differential MIN

*4 Seq Stop Request and Intentional Curve Seq Complete, Then The Seq Goes to

*3

Seq StopCheck *4



Pump Characteristic CurveEmergency Pump

Representative Motor Performance Data (Calculated)223.8kW / 3 phase / 440V / 60Hz / Y400

100

90

80

70

60

50

40

30

20

10

0

200

180

160

140

120

100

80

60

40

20

0 0 100 200 300 400 500 600 700 800 900 1000

250

225

200

175

150

125

100

75

50

25

0

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

Flow (m3/h)

Liquid: LNGSpecific Gravity: 0.500Rated Flow: 550 m3/hRated Head: 155 metresImpeller Dia: 332 mm

NPSHR

Total Head

Effic

ienc

y

Pumpdown

Min

imum

Con

t. F

low

Max

imum

Flo

w

Shaft Power at 0.50 SP GR (kW)

3600

3590

3580

3570

3560

3550

3540

3530

3520

3510

0

100

90

80

70

60

50

40

30

20

10

0

500

450

400

350

300

250

200

150

100

50

0 0 50 100 150 200 250 300


Efficiency (%)

Power Factor (%)Speed (RPM)

KW Input (kW)Current (A

mperes)

NPSHR andPumpdown (m)

Shaft power(kW)

Head(m)

Efficiency(%)

KW Input (kW) andCurrent (Amperes)

Efficiency andPower Factor (%)

Speed(rpm)

Top Bearing

Shaft

Rotor

Stator

Lower Bearing

Automatic Thrust Balancing Device

Impeller

Pump Inlet

Illustration 4.3.3a Emergency Cargo Pump


4.3.3 Emergency Cargo Pump(See Illustration 4.3.3a)

Specification

Manufacturer: Ebara International CorporationPump model: 8ECR-12No. of stages: 1Operating temperature: -163°CCapacity rated flow: 550 m3/hRated head: 155 mPower rated: 171 kWEfficiency: 67.8%Rotational speed: 3,560 rpm

Each cargo tank is equipped with an emergency pump well.

This pump well has a foot valve which is held in the closed position by highlyloaded springs.

Should a failure of either one or both main cargo pumps in one tank require theuse of the emergency pump, it is lowered into the emergency pump well afterthe well has been purged with nitrogen.

The weight of the emergency pump overcomes the compression of the springsto open the foot valve.

A small flow of nitrogen should be maintained whilst the pump is beinginstalled. (See section 7.4 Emergency Cargo Pump Installation.)

(Note ! Before undertaking this operation it is important to reduce the tankpressure to near to atmospheric pressure and to keep at this level throughoutthe entire operation.)

Electrical connections are made to the fixed junction box which is locatedadjacent to each pump well.

A dedicated starter is available with one circuit breaker which is placed in No.1cargo switchboard (panel CGP-O13). A changeover selection switch is fittedon the same panel for whichever tank the emergency pump is placed.

All safety devices are transferred to the emergency pump when the circuitbreaker is engaged, as they are the same for the main cargo pumps. The samestarting procedures and schematic mimics are used as that for the main cargopumps.


Following installation into a cargo tanks, it is most important that theemergency cargo pump is fully submerged in liquid LNG and remains in thatcondition for a minimum of one hour. This is in order that thermal stabilisationcan take place. Only after this point can the pumps be started. Failure to do somay result in severe damage to the pump.

Caution !The emergency cargo pump must not be started or operated against aclosed discharge valve, due to potential insufficient cooling, lubricationand excessive vibration.

Caution !The emergency cargo pump must only be operated between the minimumcontinuous capacity (195.7 m3/h) and maximum capacity (650 m3/h).




Issue: 1 4.4 Cargo Compressors Page 1 of 8

TIIAS

ZT

ElectricMotor

GearBox

Vapour In

Vapour Out

InletGuideVanesActuator

Gas Tight Bulkhead

DPT

DPT

Key

LNG Vapour

Gaseous Nitrogen

Lub Oil

Instrument Air

Steam Supply

Electric

Instrumentation

Illustration 4.4.1a HD Gas Compressor

TIIAS

ZI

ZT

ZIIAS

ZAHIAS

ZAHHIAS

ZSH ZSHH ZAHH

XI

XSH

XSHH

TTTT

XI

XAH

TSHTAH TSHH

TAHIAS

XAH

TAHHIAS

TAHH

XAH

XAHH

XT

ZAH

TIIAS

ZT

TIHD9n6

THHD9n3HDTRIP08

ElectricDriven

L.O.Pumpin Safe Area

PLHD9n3

CN911CN912

CN907CN908

HDTrip09

TIHD9n7

DIHD9n1

TIHD9n5

XIHD9n1FCHD9n

VIHD9n1-P

TICG9n2

HDTrip01

SurgeLine

PICG9n2

XBHD9n3

TIHD9n9 HDTrip05

HDTrip06

XBHD9n1

HDTrip02

HDTrip04

CN903CN904

HDTrip07 HD

Trip03

To VentMastNo.4

PSLPALPAL

IAS

PSL

TIIAS

TIIAS

TSHH

PI

PALLPALLIAS

Trip

Trip

Trip

Trip

Trip

Trip

Trip Trip

Trip

Trip

Trip

Trip

XAHH Trip

HDTrip10

Trip

Trip

Trip

Trip

TSH TSH

XT XT

XE XE

TE TE

PALL

ZLH

ZLHIAS

ZLL

FIC ZIIAS

FIIAS

ZLLIAS

PI

PIIAS

PALLIAS

PAL

PALIAS

PSL

ZSL ZLLIAS

PALL

PAL

PALL PALLIAS

PALIAS PALL

IAS

TIIAS

TIIAS

PSLL

TT TSH TAH TSHH TAHH

TALIAS

TIIAS

TAHIAS

TAHHIAS

TSLTAL

TE

PSLL

ZI

ZSHZSL

ZC

PT

PT

TT

TAHHTSHH

TAHH

TE

TT TIIAS

TSH

TAH

TAHIAS

TE

PT

ZI

PILL

PSL

TT

TE

ZC

ZT

ZSL

L.O. Sump

FI


4.4 Gas Compressors

4.4.1 HD Compressors

Two high duty (HD) compressors, installed in the cargo machinery room ondeck, are provided for handling gaseous fluids; LNG vapour and variousmixtures of LNG vapour, inert gas or air during the cooling down, cargooperation and tank treatments.

Two low duty (LD) compressors, installed in the cargo machinery room ondeck, are provided for handling the LNG vapour for the boiler produced by thenatural boil off and forced vaporization, which is used as fuel.

The HD and LD compressors are driven by electric motors, installed in anelectric motor room segregated from the compressor room by a gas tightbulkhead; the shaft penetrates the bulkhead with a gas tight shaft seal.

HD CompressorsManufacturer: Atlas Copco ACEModel: GT 050 T1K1Type: Centrifugal, single stage, fixed speed with

adjustable guide vanesVolume flow: 32,000 m3/hInlet pressure: 103.0kPa abs.Outlet pressure: 200.0kPa abs.Inlet temperature: -140°CDischarge temperature: -109°CShaft speed: 11,531 rpmMotor speed: 3,560 rpmRated motor power: 950 kW

The compressors are operated locally or from the CACC.

The following conditions trip the compressors:

Safeties in ESDS

Differential pressure: vapour header/atmospheric pressure = 0.3kPa

Differential pressure: vapour header/IBS pressure header = 0kPa

Tank No.1, 2, 3 or 4 - very high liquid level

Safeties on local control system (oil temperature, oil pressure, discharge gas temperature, seal gas pressure)

Electric power failure

Ventilation flow failure in the electric motor room

Compressor Systems

Seal Gas System

The seal gas system is provided to seal the compressor shaft opening from therelease of explosive LNG vapour. The seal consists of two chambers. The firstchamber on the impeller side allows any leak off gas to be drawn back to thesuction side of the compressor, while the second chamber is fed with drynitrogen. Seal gas is nitrogen produced by the nitrogen generators on board.

The system is maintained by a pressure control valve where seal gas pressureis always higher than the suction pressure (usually adjusted at 30kPa). To avoidLNG vapour leaking to the atmosphere during standstill, a vent line valve isfitted which leads to No.4 vent mast. This vent line valve must be closed priorto starting the compressor.

Lubricating Oil System

Lubricating oil in the system is stored in a vented 320 litre sump. An integratedsteam immersion heater with thermostatic switch is fitted in the sump tomaintain a constant positive temperature of at least 25°C and avoid condensa-tion when the compressors are stopped.

Lubricating oil is supplied from the sump through separate suction strainerscreens and one of the two LO pumps. The discharge from the pumps isthrough check valves to a common LO supply line feeding the gearbox andbearings. The main operational pump is driven by the high speed shaft gear.Upon failure of the driven pump, the standby electric motor driven auxiliarypump is energised immediately and a remote alarm is initiated to indicateabnormal conditions. The standby electric motor driven auxiliary pump is alsoused to start the compressors.

The LO passes through a fresh water cooled oil cooler and a thermal bypasstemperature control valve, to maintain the LO inlet temperature at approxi-mately 48°C. The oil supply to the bearings is fed via a 25 micron duplex filterwith an automatic continuous flow switch changeover valve.

A pressure control valve regulates the oil flow to the bearings. Excess oil isbypassed and discharged to the sump. Pump relief valves act as back up andare set at 4 bar.

The LO system feeds the following:

Journal bearing on both sides of the high speed shaft

Journal bearing on the driven end of the low speed shaft

Integral thrust and journal bearing on the non-driven end of low speedshaft

Sprayers for the gear wheelss

Surge Control System

An automatic surge control system is provided to ensure that the compressorflow rate does not fall below the designed minimum. Below this rate, the gasflow will not be stable and the compressor will be liable to surge, causing shaftvibration which may result in damage to the compressor.

All the gas compressors are equipped with an automatic surge control systemwhich consists of:

A flow transmitter

A compressor differential pressure transmitter

A ratio station

An anti-surge controller

A bypass valve on the gas stream

On the basis of a preset ratio between the gas flow and compressor differentialpressure signals, the anti-surge controller produces a signal which modulatesthe compressor bypass valve.

Inlet Guide Vanes

To achieve the required gas flow, the compressors have inlet guide vanes fittedat the suction end.

The vanes are operated by pneumatic actuators which receive control signalsfrom the flow controller.

Rotation of the vanes is possible through an angle of 100°. The position isindicated both locally and at the CACC.

Bulkhead Shaft Seals

Each compressor shaft is equipped with a forced nitrogen bulkhead shaft seal,preventing any combustible gas from entering the electric motors room.

The seals are of flexibox supply. They are fixed on the bulkhead and float onthe shafts, supported by two ball bearings.




TIIAS

ZT

ElectricMotor

GearBox

Vapour In

Vapour Out


Gas Tight Bulkhead

DPT

DPT

Key

LNG Vapour

Gaseous Nitrogen

Lub Oil

Instrument Air

Steam Supply

Electric

Instrumentation

Illustration 4.4.1a HD Gas Compressor

TIIAS

ZI

ZT

ZIIAS

ZAHIAS

ZAHHIAS

ZSH ZSHH ZAHH

XI

XSH

XSHH

TTTT

XI

XAH

TSHTAH TSHH

TAHIAS

XAH

TAHHIAS

TAHH

XAH

XAHH

XT

ZAH

TIIAS

ZT

TIHD9n6

THHD9n3HDTRIP08

ElectricDriven


PLHD9n3

CN911CN912

CN907CN908

HDTrip09

TIHD9n7

DIHD9n1

TIHD9n5

XIHD9n1FCHD9n

VIHD9n1-P

TICG9n2

HDTrip01

SurgeLine

PICG9n2

XBHD9n3

TIHD9n9 HDTrip05

HDTrip06

XBHD9n1

HDTrip02

HDTrip04

CN903CN904

HDTrip07 HD

Trip03

To VentMastNo.4

PSLPALPAL

IAS

PSL

TIIAS

TIIAS

TSHH

PI

PALLPALLIAS

Trip

Trip

Trip

Trip

Trip

Trip

Trip Trip

Trip

Trip

Trip

Trip

XAHH Trip

HDTrip10

Trip

Trip

Trip

Trip

TSH TSH

XT XT

XE XE

TE TE

PALL

ZLH

ZLHIAS

ZLL

FIC ZIIAS

FIIAS

ZLLIAS

PI

PIIAS

PALLIAS

PAL

PALIAS

PSL

ZSL ZLLIAS

PALL

PAL

PALL PALLIAS

PALIAS PALL

IAS

TIIAS

TIIAS

PSLL


TALIAS

TIIAS

TAHIAS

TAHHIAS

TSLTAL

TE

PSLL

ZI

ZSHZSL

ZC

PT

PT

TT

TAHHTSHH

TAHH

TE

TT TIIAS

TSH

TAH

TAHIAS

TE

PT

ZI

PILL

PSL

TT

TE

ZC

ZT

ZSL

L.O. Sump

FI


Operating Procedures

To prepare the HD compressors for running.

a) Check the LO level in the sump tank.

b) Start the LO heater about 30 minutes (depending on ambienttemperature) prior to the expected compressor start up.

c) Close the seal chamber vent line valve.

d) Open the nitrogen seal gas supply manual valve.

e) Open the compressor suction and discharge valves.

f) Run the auxiliary LO pump to warm up the gearbox and bearings.Check the LO system for leaks.

g) Open the cooling water inlet and outlet for the LO cooler.

h) Open the instrument air supply to the control panel.

i) Switch on power to the control cabinet. Reset any alarms.

j) At least two alternators should be coupled to the mainswitchboard so that there is sufficient power available at the cargoswitchboards.

In the CACC

k) Select mimic C-19 (HD compressor) for the appropriateoperation.

l) The anti-surge controller is to be set at minimum i.e. the bypassvalve is fully open.

m) Start the compressor. The shaft vibration monitoring system isreleased after approximately 14 seconds.


Instrument Number

Description

HD compressor shaft seal-gas pressure lowPAL 6305 0.15 bar g. H6HD compressor bulkhead seal-gas pressure lowPAL 6307 0.05 bar g. H32HD compressor bearing temperature shaft highTAH 8301 95°C H11HD compressor bulkhead seal-gas temp. highTAH 8307 70 °C H14HD compressor Suction Pressure lowPAL 6312 1.2kPa H29HD compressor LO temperature after cooler highTAH 8350 60°C H12HD compressor LO tank level lowLAL 5357 230mm H9HD compressor shaft vibration highXAH 9201/2 31µm H15HD compressor LO filter differential pressure lowPDAH6353 0.8 bar g.HD compressor LO pressure lowPAL 6355 1.2 bar g. H7HD compressor discharge temperature highTAH 8317 80 °C H10HD compressor shaft displacement highZAH 3201 ± 0.15 mm H27HD compressor LO temperature before cooler lowTAL 8350 25 °C H31HD compressor LO tank oil temperature lowTSL 8457 25 °C

Pre-alarm Switch Point Yellow Indication Light

Instrument Number

Description

HD compressor LO pressure low lowPALL 6454 0.9 bar g. H18HD compressor shaft seal-gas pressure low lowPALL 6405 0.1 bar g. H22HD compressor bulkhead seal-gas press. low lowPALL 6407 0.03 bar g. H16HD compressor bulkhead seal-gas temp. high HighTAHH 8407 130°C H21HD compressor discharge temperature high highTAHH 8416 95°C H19HD compressor bearing temp. shaft high highTAHH8401 105°C H20HD compressor shaft displacement high highZAHH 3201 ± 0.20 mm H24HD compressor suction pressure low lowPALL 6411 0.9 kPa H17HD compressor shaft vibration high highXAH 9021/2 48µm H23HD compressor motor failureES 1400 Failure H25External troubleES Trouble H25LO temperature after cooler high highTAHH 8450 65°C H28

Shut-down Trip Setting Yellow Indication Light

HD Alarm Points

HD Compressor Shutdown Trip Points

HD compressor LO tank oil temperature highTSH 8457 70 °C



TIIAS

ZT

ElectricMotor

GearBox

Vapour In

Vapour Out


Gas Tight Bulkhead

DPT

DPT

Key

LNG Vapour

Gaseous Nitrogen

Lub Oil

Instrument Air

Steam Supply

Electric

Instrumentation

Illustration 4.4.2a LD Gas Compressor

TIIAS

ZI

ZT

ZIIAS

ZAHIAS

ZAHHIAS

ZSH ZSHH ZAHH

XI

XSH

XSHH

TTTT

XI

XAH

TSHTAH TSHH

TAHIAS

XAH

TAHHIAS

TAHH

XAH

XAHH

XT

ZAH

TIIAS

ZT

TILD9n6

THLD9n3LDTRIP08

ElectricDriven


PLLD9n3

CN913CN914

CN909CN910

LDTrip09

TILD9n7

DILD9n1

TILD9n5

XILD9n1FCLD9n

XCLD9nVF

TICG9n2

LDTrip01

SurgeLine

PICG9n2

XBLD9n3

TILD93n LDTrip05

LDTrip06

VCGD902/905

LDTrip02

LDTrip04

CN905CN906

LDTrip07 LD

Trip03

To VentMastNo.4

PSLPALPAL

IAS

PSL

TIIAS

TIIAS

TSHH

PI

PALLPALLIAS

Trip

Trip

Trip

Trip

Trip

Trip

Trip Trip

Trip

Trip

Trip

Trip

XAHH Trip

LDTrip10

Trip

Trip

Trip

Trip

TSH TSH

XT XT

XE XE

TE TE

PALL

ZLH

ZLHIAS

ZLL

FIC ZIIAS

FIIAS

ZLLIAS

PI

PIIAS

PALLIAS

PAL

PALIAS

PSL

ZSL ZLLIAS

PALL

PAL

PALL PALLIAS

PALIAS PALL

IAS

TIIAS

TIIAS

PSLL


TALIAS

TIIAS

TAHIAS

TAHHIAS

TSLTAL

TE

PSLL

ZI

ZSHZSL

ZC

PT

PT

TT

TAHHTSHH

TAHH

TE

TT TIIAS

TSH

TAH

TAHIAS

TE

PT

ZI

PILL

PSL

TT

TE

ZC

ZT

ZSL

L.O. Sump

FI


4.4.2 LD Compressors

Manufacturer: Atlas Copco ACEModel: GT 026 T1K1Type: Centrifugal, single stage, variable

speed with adjustable guide vanes.Volume flow: 8,500 m3/hInlet pressure: 103kPa abs.Outlet pressure: 200kPa abs.Minimum inlet temperature: -140°CMaximum shaft speed: 13,997 ~ 27,994 rpmMotor speed: 1,780 ~ 3,560 rpmRated motor power: 430kW

The compressors are operated locally or from the CACC.

The following conditions trip the compressors:

Safeties in ESDS

Differential pressure: vapour header/atmospheric pressure = 0.3kPa

Differential pressure: vapour header/IBS pressure header = 0kPa

Tank No.1, 2, 3 or 4 very high liquid level

Safeties on local control system (oil temperature, oil pressure, discharge gas temperature, seal gas pressure)

Electric power failure

Ventilation flow failure in the electric motor room

Compressor sub-systems

Seal Gas System

The seal gas system is provided to seal the compressor shaft opening from therelease of explosive LNG vapour. The seal consists of two chambers. The firstchamber on the impeller side allows any leak off gas to be drawn back to thesuction side of the compressor, while the second chamber is fed with drynitrogen. Seal gas is nitrogen produced by the nitrogen generators on board.

The system is maintained by a pressure control valve where seal gas pressureis always higher than the suction pressure (usually adjusted at 30kPa). To avoidLNG vapour leaking to the atmosphere during standstill, a vent line valve isfitted which leads to No.4 vent mast. This vent line valve must be closed priorto starting the compressor.

Lubricating Oil System

Lubricating oil in the system is stored in a vented 320 litre sump. An integratedsteam immersion heater with thermostatic switch is fitted in the sump tomaintain a constant positive temperature of at least 25°C and avoid condensa-tion when the compressors are stopped.

Lubricating oil is supplied from the sump through separate suction strainerscreens and one of the two LO pumps. The discharge from the pumps isthrough check valves to a common LO supply line feeding the gearbox andbearings. The main operational pump is driven by the high speed shaft gear.Upon failure of the driven pump, the standby electric motor driven auxiliarypump is energised immediately and a remote alarm is initiated to indicateabnormal conditions. The standby electric motor driven auxiliary pump is alsoused to start the compressors.

The LO passes through a fresh water cooled oil cooler and a thermal bypasstemperature control valve, to maintain the LO inlet temperature at approxi-mately 48°C. The oil supply to the bearings is fed via a 25 micron duplex filterwith an automatic continuous flow switch changeover valve.

A pressure control valve regulates the oil flow to the bearings. Excess oil isbypassed and discharged to the sump. Pump relief valves act as back up andare set at 4 bar.

The LO system feeds the following:

Journal bearing on both sides of the high speed shaft

Journal bearing on the driven end of the low speed shaft

Integral thrust and journal bearing on the non-driven end of low speed shaft

Sprayers for the gear wheels

Surge Control System

An automatic surge control system is provided to ensure that the compressorflow rate does not fall below the designed minimum. Below this rate, the gasflow will not be stable and the compressor will be liable to surge, causing shaftvibration which may result in damage to the compressor.

All the gas compressors are equipped with an automatic surge control systemwhich consists of:

A flow transmitter

A compressor differential pressure transmitter

A ratio station

An anti-surge controller

A bypass valve on the gas stream

On the basis of a preset ratio between the gas flow and compressor differentialpressure signals, the anti-surge controller produces a signal which modulates acompressor bypass valve.

Inlet Guide Vanes

To achieve the required gas flow, the compressors have inlet guide vanes fittedat the suction end.

The vanes are operated by pneumatic actuators which receive control signalsfrom the flow controller.

Rotation of the vanes is possible through an angle of 100°. The position isindicated both locally and at the CACC.

Bulkhead Shaft Seals

Each compressor shaft is equipped with a forced nitrogen bulkhead shaft seal,preventing any combustible gas from entering the electric motors room.

The seals are of flexibox supply. They are fixed on the bulkhead and float onthe shafts, supported by two ball bearings.




TIIAS

ZT

ElectricMotor

GearBox

Vapour In

Vapour Out


Gas Tight Bulkhead

DPT

DPT

Key

LNG Vapour

Gaseous Nitrogen

Lub Oil

Instrument Air

Steam Supply

Electric

Instrumentation

Illustration 4.4.2a LD Gas Compressor

TIIAS

ZI

ZT

ZIIAS

ZAHIAS

ZAHHIAS

ZSH ZSHH ZAHH

XI

XSH

XSHH

TTTT

XI

XAH

TSHTAH TSHH

TAHIAS

XAH

TAHHIAS

TAHH

XAH

XAHH

XT

ZAH

TIIAS

ZT

TILD9n6

THLD9n3LDTRIP08

ElectricDriven


PLLD9n3

CN913CN914

CN909CN910

LDTrip09

TILD9n7

DILD9n1

TILD9n5

XILD9n1FCLD9n

XCLD9nVF

TICG9n2

LDTrip01

SurgeLine

PICG9n2

XBLD9n3

TILD93n LDTrip05

LDTrip06

VCGD902/905

LDTrip02

LDTrip04

CN905CN906

LDTrip07 LD

Trip03

To VentMastNo.4

PSLPALPAL

IAS

PSL

TIIAS

TIIAS

TSHH

PI

PALLPALLIAS

Trip

Trip

Trip

Trip

Trip

Trip

Trip Trip

Trip

Trip

Trip

Trip

XAHH Trip

LDTrip10

Trip

Trip

Trip

Trip

TSH TSH

XT XT

XE XE

TE TE

PALL

ZLH

ZLHIAS

ZLL

FIC ZIIAS

FIIAS

ZLLIAS

PI

PIIAS

PALLIAS

PAL

PALIAS

PSL

ZSL ZLLIAS

PALL

PAL

PALL PALLIAS

PALIAS PALL

IAS

TIIAS

TIIAS

PSLL


TALIAS

TIIAS

TAHIAS

TAHHIAS

TSLTAL

TE

PSLL

ZI

ZSHZSL

ZC

PT

PT

TT

TAHHTSHH

TAHH

TE

TT TIIAS

TSH

TAH

TAHIAS

TE

PT

ZI

PILL

PSL

TT

TE

ZC

ZT

ZSL

L.O. Sump

FI



To prepare the LD compressors for running.

a) Check the LO level in the sump tank.

b) Start the LO heater about 30 minutes (depending on ambienttemperature) prior to the expected compressor start up.

c) Close the seal chamber vent line valve.

d) Open the nitrogen seal gas supply manual valve.

e) Open the compressor suction and discharge valves.

f) Run the auxiliary LO pump to warm up the gearbox and bearings.Check the LO system for leaks.

g) Open the cooling water inlet and outlet for the LO cooler.

h) Open the instrument air supply to the control panel.

i) Switch on power to the control cabinet. Reset any alarms.

j) At least two alternators should be coupled to the mainswitchboard so that there is sufficient power available at the cargoswitchboards.

In the CACC

k) Select the mimic for the LD compressor appropriate operation tobe carried out.

l) The anti-surge controller is to be set at minimum i.e the bypassvalve is fully open.

m) Start the compressor. The shaft vibration monitoring system isreleased after approximately 14 seconds.

n) Switch the compressor to automatic mode.


Instrument Number

Description

LD Compressor Shaft Seal-Gas Pressure LowPAL 6305 0.15 bar g. H6LD Compressor Bulkhead Seal-Gas Pressure LowPAL 6307 0.05 bar g. H32LD Compressor Bearing Temperature Shaft HighTAH 8301 95°C H11LD Compr.. Bulkhead Seal-Gas Temperature HighTAH 8307 70 °C H14LD Compressor Suction Pressure LowPAL 6312 1.2 kPa H29LD Compr Lub Oil Temp. After Cooler HighTAH 8350 60°C H12LD Compressor Oil Tank Level LowLAL 5357 230mm H9LD Compressor Shaft Vibration HighXAH 9201/2 31µm H15LD Compressor Lub Oil Filter Diff. Pressure LowPDAH6353 0.8 bar g.LD Compressor Lub Oil Pressure LowPAL 6355 1.2 bar g. H7LD Compressor Discharge Temperature HighTAH 8317 80 °C H10LD Compressor Shaft Displacement HighZAH 3201 ± 0.15 mm H27LD Compr..Lub Oil Temp. Before Cooler LowTAL 8350 25 °C H31LD Compressor L.O. Tank Oil Temperature LowTSL 8457 25 °C

Pre-alarm Switch Point Yellow Indication Light

Instrument Number

Description

LD Compressor Lub Oil Pressure Low LowPALL 6454 0.9 bar g. H18LD Compressor Shaft Seal-Gas Pressure Low LowPALL 6405 0.1 bar g. H22LD Comp. Bulkhead Seal-Gas Pressure Low LowPALL 6407 0.03 bar g. H16LD Comp. Bulkhead Seal-Gas Temp. High HighTAHH 8407 80°C H21LD Compressor Discharge Temperature High HighTAHH 8416 95°C H19LD Comp. Bearing Temperature Shaft High HighTAHH8401 105°C H20LD Compressor Shaft Displacement High HighZAHH 3201 ± 0.20 mm H24LD Compressor Suction Pressure Low LowPALL 6411 0.9 kPa H17LD Compressor Shaft Vibration High HighXAH 9021/2 48µm H23LD Compressor Motor FailureES 1400 Failure H25External TroubleES Trouble H25LD Lub Oil Temperature After Cooler High HighTAHH 8450 65°C H28


LD Alarm Points

LD Compressor Shut-down Trip Points

LD Compressor L.O. Tank Oil Temperature HighTSH 8457 70 °C


Issue: 1 4.5 Boil-Off/Warm-Up Heaters Page 1 of 4

Illustration 4.5a Boil-Off/Warm-Up Heater

Key

LNG Vapour

Instrument Air

Steam Supply

Electric

Instrumentation

TISTM95TISTM96

XACG93XACG94

Common TripAlarm

LHX3M

G/HTRTrip01

G/HTRTrip02

G/HTRTrip03

Trip

Trip

Trip

HS

ZS

HY

Trip

Trip

LS

TE TSHH

LS

TSLL

TELI

LSHH TSLL

LSH TT

ZLHIAS

HIC HS ZS

TTTI

TIIAS

TICIAS

TALIAS

TAHIAS

TSHH

TAHHIAS

HY

PI

ZLHIAS

TALLIAS

TIIAS

TALIAS

TALIAS

TALIAS

TALIAS

LAHIAS

LAHHIAS

Trip

Trip

HIC

SD546FSD550F

SD548FSD552F

SD545FSD549F

Vent

ST522 ST521

ST526 ST525

CG913CG915

CG914CG916

Boil-Off Warm-up Heater

FromCompressorRoom

PT

Steam

Split Range Temperature

Control


4.5 Boil-Off/Warm-Up Heater

General description

There are two steam heated boil-off/warm-up heaters located in the cargomachinery room, which is situated on the starboard side of the main deck.

The heaters are of the shell and tube type.

The heaters are used for the following functions:

Heating the LNG vapour which is delivered by either of the HDcompressors at the specified temperature for warming up of cargotanks before gas freeing.

Heating product from the forcing vaporizer in conjunction withthe HD compressors, for the operation of purging cargo tanks withLNG prior to cooldown.

Heating boil-off gas supplied to the main boilers via the LDcompressors (or free flow).

! CautionWhen returning heated vapour to the cargo tanks, the temperature at theheater outlet should not exceed +85°C, to avoid possible damage to thecargo tank insulation and safety valves.

Specification:

Manufacturer: Cryostar Model: 65-UT-38/34-3.2 Type: Horizontal shell and U-tube heat

exchangerRated capacity: 16,000 ~ 24,500 kg/hHeating medium (steam): 1,750 ~ 3,030 kg/hVapour outlet temperature: +15°C ~ +80°CNo. of sets: 2

Operating Procedure in Warming Up Configuration

a) Open the shell side vent valve.

b) Open the shell side condensate valves and check the drains.

c) Crack open the manual steam supply valve on the respectiveheater. (Ensure the steam to deck is available and the cargomachinery room isolating valve is open, ST576, located outboardof No.1 LD compressor.)

d) When all the air has been expelled from the shell, shut the ventvalve.

e) When water has been drained from the shell, shut the drain valve.

The temperatures and pressures for the venting and warming up of the heatershould be approximately 30 minutes.

f) Slowly open up the steam inlet valve.

g) Set the LNG vapour lines as detailed for the operation and theheater to be put in use.

h) In the CACC, set the controls for the heater to the ON position onthe IAS, mimic C-12.

i) Open the instrument air supply to the controls for the heater.

j) Check the condensate level in the sight glass.

k) Set the temperature and level controller to the correct settings forthe operation being undertaken (+80°C for tank warm-up).

l) Open the hydraulic operated gas inlet and manually operatedoutlet valves.

m) Monitor the gas vapour outlet and condensate temperatures.

On completion of the operation.

a) Switch the auto-control to manual.

b) Close the gas supply and outlet valve on the heater.

c) Close the steam supply valve to the heater when the temperatureat the heater outlet is above 0°C.

d) Open the steam side vent, then open the drain when all the steamhas vented.

Controls and Settings

The gas outlet temperature is controlled by controllers CG941, CG945 on theinlet and CG945, CG947 on the gas heater bypass lines respectively.

The steam condensate from the heater is returned to the drains system via thegas-vent drains tank, which is fitted with a gas detector sampling point.

Boil-Off Gas Heater Configuration

The same procedure is followed for venting and warming through the heater asdescribed above, except that the temperature control is set for a gas outlettemperature of approximately +25°C.

The LNG lines will be set for using one of the LD compressors to deliver thegas to one of the heaters. No.1 heater is the designated heater for this operation,although No.2 heater can be used by opening the cross connecting isolatingvalve CG920.

When the heater has been vented and warmed through, proceed as follows:

a) Slowly open the manually operated steam inlet valve ST521.

b) Check the condensate level.

c) Set the LNG vapour lines as detailed for the operation to be taken.

d) Open the vapour outlet valve CG914 and vapour inlet valveCG913.

e) In the CACC, set the controls for the boil-off heater on the IAS,mimic C-12.

f) Open the control air supply to the boil-off gas heater controls.

g) Set the temperature and level controllers to the correct settings forgas burning of +25°C.

h) Monitor the gas vapour outlet and condensate temperatures.




Illustration 4.5a Boil-Off/Warm-Up Heater

Key

LNG Vapour

Instrument Air

Steam Supply

Electric

Instrumentation

TISTM95TISTM96

XACG93XACG94

Common TripAlarm

LHX3M

G/HTRTrip01

G/HTRTrip02

G/HTRTrip03

Trip

Trip

Trip

HS

ZS

HY

Trip

Trip

LS

TE TSHH

LS

TSLL

TELI

LSHH TSLL

LSH TT

ZLHIAS

HIC HS ZS

TTTI

TIIAS

TICIAS

TALIAS

TAHIAS

TSHH

TAHHIAS

HY

PI

ZLHIAS

TALLIAS

TIIAS

TALIAS

TALIAS

TALIAS

TALIAS

LAHIAS

LAHHIAS

Trip

Trip

HIC

SD546FSD550F

SD548FSD552F

SD545FSD549F

Vent

ST522 ST521

ST526 ST525

CG913CG915

CG914CG916

Boil-Off Warm-up Heater

FromCompressorRoom

PT

Steam

Split Range Temperature

Control


On completion of the operation:

a) After the LD compressor has been shut down and the gas supplyvalve to the engine room shut, close inlet valve to the heaterCG913.

b) Shut the steam inlet valve ST521.

c) Open the steam side vent and open the drain valve when all thepressure is off the heater.

Controls and Settings

The gas outlet temperature is controlled by controllers CG941 on the inlet andCG943 on the bypass respectively.

The steam condensate from the heater is returned to the drains system via thegas-vent drains tank, which is fitted with a gas detector sampling point.

The following alarms and trips are available:

Issue: Draft 1 4.5 Boil-Off/Warm-Up Heaters Page 4 of 4

Instrument Number

Description

Boil-Off/Warm-Up Heater Cond. Level HighLSH4 Level SwitchBoil-Off/Warm-Up Heater Cond. Temp. LowTAL4 95°C IASBoil-Off/Warm-Up Heater Temp. Control ValveNo.1 Remote/Local PositionBoil-Off/Warm-Up Heater Temp. Control ValveNo.2 Remote/Local Position

Pre-alarm Switch Point Remark

Instrument Number

Description

Boil-Off/Warm-Up Heater Cond. Level High HighLSHH4 Level Switch Heater TripBoil-Off/Warm-Up Heater Cond. Temp. Low LowTSLL4 80°C Heater Trip, IASBoil-Off/Warm-Up Heater Outlet Temp. High HighTAHH2 200°C Heater Trip, IASBoil-Off/Warm-Up Heater Local Hand TripHSBoil-Off/Warm-Up Heater Common Alarm TripBoil-Off/Warm-Up Heater Outlet Temp. High/LowTT2 IAS Internal Alarm


Boil-Off/Warm-Up Heater Alarm Points

Boil-Off/Warm-Up Heater Shut Down/Trip Points


Issue: 1 4.6 LNG Vaporizer Page 1 of 2

Illustration 4.6a LNG Vaporiser

Key

LNG Vapour

Instrument Air

Steam Supply

Electric

Instrumentation

TISTM93XACG90

Common TripAlarm

LHX10

LNG/VPRTrip03

LNG/VPRTrip02

LNG/VPRTrip01

Trip

Trip

HS

ZS

HY

Trip

Trip

LS

LS

TSLL

TELI

PT

TI

LSHH TSLL

LSH TT

PIALIAS

HIC HS ZS

TIPI

PIT

PIIAS

FICFIIAS

TI

TICIAS

TT

TIIAS

TALIAS

TAHIAS

HY

PI

XAIAS

TALLIAS

TIIAS

TALIAS

TALIAS

XAIAS

HS

LAHIAS

LAHHIAS

TripTrip

HIC

Vent

LNG Vaporiser

VapourInlet

DTPTE FI

Steam

ST523F

CS951

CS903

CS904

ST527F

FlowMeter

TCCG93

TCCG93

FCCG91 FCCG91PCCG91

SD554F

SD521F

SD553F


4.6 LNG Vaporizer

General Description(See Illustration 4.6a)

The LNG vaporizer is used for vaporizing LNG liquid, to provide gas whendisplacing inert gas from the cargo tanks with LNG vapour and for maintainingthe pressure in the tanks when LNG is being discharged and vapour is notsupplied from shore.

Both the LNG and forcing vaporizers are situated in the cargo machineryroom.

SpecificationManufacturer: CryostarModel: 65-UT-38/34 -5 9Type: Horizontal Shell and ‘U’ tube designHeating medium (steam): 4,160 ~ 5,810 kg/hInlet temp of the medium: 170°C Maximum gas flow: 21,300kg/hInlet LNG temperature: -163°COutlet gas temp: -140 to 20°C

Alarms are provided on the outlet gas temperature, high level and lowtemperature of the condensate water.

The LNG vaporizer is used for the following operations:

Discharging cargo at the design rate without the availability of avapour return from the shore.

If the shore is unable to supply vapour return, liquid LNG is fedto the vaporizer by using one stripping pump or by bleeding fromthe main liquid line. The vapour produced leaves the vaporizer atapproximately -140°C and is then supplied to cargo tanks throughthe main vapour header. Vapour pressure in the cargo tanks willnormally be maintained at 110kPa abs. (minimum 104kPa abs.)during the whole discharge operation. Additional vapour isgenerated by the tank sprayer rings, the LNG being supplied bythe stripping/spray pump.

If the back pressure in the discharge piping to shore is notsufficient to have a minimum of 300 kPa at the inlet to thevaporizer, a stripping/spray pump will be used to supply liquid tothe vaporizer.

Purging of cargo tanks with gaseous NG after inerting with inertgas and prior to cooldown. LNG is supplied from the shore to thevaporizer via the stripping/spray line. The vapour produced at therequired temperature +20°C is then passed to the cargo tanks.

(Note ! This operation is the normal procedure if the cargo tanks have beeninerted with inert gas containing carbon dioxide.)

Operating ProceduresSet the LNG or nitrogen pipelines as detailed for the operation about to beundertaken. For vaporizing liquid nitrogen, a removable bend must be fitted atthe inlet to the vaporizer.

Main VaporizerTo prepare the LNG vaporizer for use.


b) Crack open the shell side drain valve. Check that the condensatedrain valves SD554 and SD556 are open.

c) Crack open the steam supply manual valve ST523. Ensure thesteam to deck is available and the cargo machinery room isolatingvalve ST576 is open, located outboard of No.1 LD compressor.

d) When all air is expelled from the shell, shut the vent valve.

After about 30 minutes when pressures and temperatures have stabilised on thevaporizer.

e) Slowly open fully the steam inlet manual valve.

f) Open the instrument air supply to the vaporizer controls.

g) In the CACC, set the controls for the LNG vaporizer on the IASmimic C-13.

h) Fill up the vaporizer with liquid using manual control. Check allflanges and joints for any signs of leakage.

i) When vapour is produced switch the control for liquid valve toremote and automatic.

! CautionThorough checks around the LNG vaporizer and associated flangeconnections must be conducted during operation.

On completion of operations.

a) Shut the liquid valve CS951.

b) Shut the steam supply valve ST523 when no LNG remains.

c) Open the steam side vent and then open the drain when all steamhas been vented.

d) Keep the vapour side valve open to the system until the vaporizerreaches ambient temperature.

Control

Process control is on the outlet temperature from vaporizer, with high and lowtemperature alarms, this is controlled on the temperature control valve (TCV)CS902.

The steam condensate from the vaporizer is returned to the drains system viathe gas-vent drains tank, which is fitted with a gas detector sampling point.

Issue: 1 4.6 LNG Vaporizer Page 2 of 2

Instrument Number

Description

LNG Vaporizer Cond. Level HighLSH4LNG Vaporizer Cond. Level High HighTAL4LNG Vapr. Flow Cont. Valve Remote/Local PositionLNG Vapr. Temp. Cont. Valve Remote/Local PositionLNG Vapr. Outlet Temp. High / LowTT2

RemarksSet Point

Level SwitchIAS

IAS Int. Alarm

Instrument Number

Description

LNG Vaporizer Cond. Level High High (Level Switch)LSHH4LNG Vaporizer Cond. Temp Low LowTSLL4LNG Vaporizer Local Hand Trip HSLNG Vaporizer Common Trip Alarm

RemarksSet Point

Vaporizer TripVapr. Trip IAS


Issue: 1 4.7 Forcing Vaporizer Page 1 of 2

Illustration 4.7a Forcing Vaporiser

Key

LNG Vapour

Instrument Air

Steam Supply

Electric

Instrumentation

TISTM94XACG91

Common TripAlarm

Mist SeperatorCondensate Level

High For Trip

LHX20

FORC VPRTrip01

FORC VPRTrip02

FORC VPRTrip03

Trip

Trip

HS

ZS

HY

FORC VPRTrip04

Trip

Trip

LS

LS

TSLL

TELI

LSHH TSLL

LSH TT

HIC HS ZS

TIPI

PIT

PIIAS

FIIAS

TI

TICIAS

TT

TIIAS

TALIAS

TAHIAS

HY

PI

XAIAS

TALLIAS

TIIAS

TALIAS

TI

XAIAS

HS

LAHIAS

LAHHIAS

Trip

LAHH

LSHH

Trip

Trip

HIC

Vent

Forcing Vaporiser

VapourInlet

DTPTE FI

Steam

ST524F

CS952

CS904

CS903

SD558F

SD560F

SD557F

ST528F

FlowMeter

TCCG94

TCCG94-R

FCCG92 Boiler CombustionDemand (GMS)

PCCG92


4.7 Forcing Vaporizer

General Description(See Illustration 4.7a)

The forcing vaporizer is used for vaporizing LNG liquid to provide gas forburning in the boilers to supplement the natural boil-off. Both the main andforcing vaporizers are situated in the cargo machinery room.

The forcing vaporizer is used to supplement boil-off gas for fuel gas burningup to 105% MCR.

The LNG is supplied by a stripping/spray pump. LNG flow is controlled by anautomatic inlet feed valve which receives its signal from the boilerscombustion control system.

SpecificationManufacturer: CryostarModel: 34-UT-25/21 -3.6. Type: Horizontal shell and ‘U’ tube designHeating medium (steam): 2,660 kg/hInlet temp of the medium: 170°C Maximum gas flow: 7,000 kg/hInlet LNG temperature (°C): -163°COutlet gas temp: -40°C

Alarms are provided on the outlet gas temperature, high level and lowtemperature of the condensate water.

The forcing vaporizer is equipped with a temperature control system to obtaina constant and stable discharge temperature for various ranges of operation.The temperature of the gas produced is adjusted by injecting a certain amountof bypassed liquid into the outlet side of the vaporizer through a temperaturecontrol valve and liquid injection nozzles.

A re-evaporator is also used to ensure that accumulation of non-vaporizedliquid at the vaporizer discharge is avoided and that the output is at a stabletemperature.

This is made possible by:

1) Two knitted mesh filters inserted in the gas flow path tofractionate the droplets and create the necessary turbulence totransform the small droplets injected into a fine fog of liquid gasand also to moisten the mesh wires acting as vaporizing surface.

2) Two conical baffles installed in the tube to allow eventuallyaccumulated liquid to be directed into the gas stream on the pipebottom.

Mist Separator

A mist separator is fitted downstream of the forcing vaporizer to serve as amoisture separator and prevent any carry over of liquid to the LD compressors.

Both the LNG and forcing vaporizer tube stacks are fitted with spiral wires topromote turbulence, thereby ensuring efficient heat transfer and production ofsuperheated LNG vapour at the exit of the tube nests.

SpecificationManufacturer: CryostarModel: VMS-10/12-1000 Type: Shell with in/out nozzles and drainGas flow: 7,800 kg/hService temperature: -40°C

An alarm is provided on the level of the drained LNG.

To prepare the forcing vaporizer for use.


b) Crack open the shell side drain valve. Check the condensate drainvalves SD558 and SD560 are open.

c) Crack open the steam supply manual valve ST524. Ensure thesteam to deck is available and the cargo machinery room isolatingvalve ST576 is open, located outboard of No.1 LD compressor.

d) When all the air is expelled from the shell, shut the vent valve.

After about 30 minutes when pressures and temperatures have stabilised on thevaporizer.

e) Slowly open fully the steam inlet manual valve.

f) Open the instrument air supply to the vaporizer controls.

g) In the CACC, set the controls for the forcing vaporizer on the IASmimic C-13.

h) Fill up the vaporizer with liquid using manual control. Check allflanges and joints for any signs of leakage.

i) When vapour is produced switch the control for liquid valve toremote and automatic.

! CautionThorough checks around the forcing vaporizer and the associated flangeconnections must be conducted during operation.

On completion of the operation.

a) Shut the liquid valve CS903.

b) Shut the steam supply valve ST524 when no LNG remains.

c) Open the steam side vent and then open the drain when all thesteam has been vented.

d) Keep the vapour side valve open to system until the vaporizerreaches ambient temperature.

Control

Process control is on the outlet temperature from vaporizer, with high and lowtemperature alarms, this is controlled on the temperature control valve (TCV)CS903.

The steam condensate from the vaporizer is returned to the drains system viathe gas-vent drains tank, which is fitted with a gas detector sampling point.

Issue: 1 4.7 Forcing Vaporizer Page 2 of 2

Instrument Number

Description

Forcing Vaporizer Cond. Level High (Level Switch)LSH4Forcing Vaporizer Cond. Level High High (Level Switch)LSHH4 Vaporizer. TripForcing Vaporizer Condensate Temp Low TAL4 IASForcing Vaporizer Cond. Temp Low Low (Temp Switch)TALL4 Vapr. Trip IASMist Separator Condensate Level High (Level Switch)LAHH1 Vapr. Trip IASForcing Vaporizer Local Hand TripHSForcing Vaporizer Common Trip AlarmForcing Vaporizer Flow Control Valve Remote/Local Pos.Forcing Vaporizer Temp Control Valve Remote/Local Pos.Forcing Vaporizer Outlet Temperature High / LowTT2

Set Point Remarks


Issue: 1 4.8 Custody Transfer System Page 1 of 7

Liquid Dome

High SensingRange

99%

98%

100%

95%

85%

50%

25%

0%

Mid SensingRange

Low SensingRangeTank

Bottom

Feed Through

Coaxial Cables toControl Unit via Zener Barriers

Illustration 4.8.1a Foxboro CTS

ColumnSupport

StandardSegment4 Per Tank

Main LevelSensor Column

Backup LevelSensor Column

Bottom/ReferenceSegment

InsulatedSupportBrackets

TopSegment

Independent LevelAlarm Sensor

TemperatureSensor

TemperatureSensor

Reference SegmentMain Column

Reference SegmentMain Column

Reference SegmentBack-Up Column

Reference SegmentBack-Up Column

PTFE SheathedCoaxial CablesPTFE SheathedCoaxial Cables

Bottom SegmentBack-Up SegmentBottom Segment

Back-Up Segment

Bottom SegmentMain Segment

Bottom SegmentMain Segment

PTFE SheathedCoaxial CablesPTFE SheathedCoaxial Cables

SegmentsBottom-Mid SegmentsBottom-Mid

TemperatureSensors

TemperatureSensors

InsulatedFlange

BetweenSegments

InsulatedFlange

BetweenSegments

CoaxialConnection

CoaxialConnection


4.8 Custody Transfer System

4.8.1 Foxboro Custody Transfer System

Introduction(See illustration 4.8.1a)

LNG is bought and sold on its calorific content, normally expressed in Btu’srather than on a volume or weight basis. However, at the present time there areno practical instruments available to determine the net calorific contenttransferred during loading and discharge so that for the moment this value isdetermined partly by measurement and partly by analysis of cargo calculationby means of the following formula:

Total energy transferred Q = Vd HL - VTsPvHv

TvPs

where :

V = Cargo volume loaded or discharged at an average temperature TL (m3)

d = Density of cargo at temperature TL (kg/m3)

HL = Gross heating value of the cargo (Btu/kg)

Ts = Standard temperature (°K)

Tv = Average temperature of gas in the cargo tanks (°K)

TL = Average temperature of liquid in cargo tanks (°K)

Pv = The absolute pressure of the gas in the cargo tanks, that is, gauge pressure of gas + barometric pressure (kPa)

Hv = The gross heating value of gas vapour at 15.6°C and 101.3kPa (Btu/m3). This value is assumed to be a constant 36,000 Btu/m3 based on pure methane (MLNG uses Btu/scf)

In establishing the value of the cargo transferred to and from the ship, thevessel’s responsibility is limited to measurement/calculation of the followingvalues: V, Tv, Pv. These measurements/calculations are made by ship and shorerepresentatives and are normally verified by an independent surveyor. Thevalues HL and d are determined ashore at the loading and discharge ports andthe calculations are completed by the buyers and sellers.

The quantity of cargo delivery is expressed in MMBtu or tonnes.

Custody Transfer MeasurementsThe Foxboro Custody Transfer CT-IV System provides the high accuracy mea-surements and data logging of levels, temperatures and pressures required forthe calculation of total LNG cargo loaded or discharged.

All custody transfer measurements can be displayed on a VDU in the CACCand in addition liquid level measurements of each tank can be individuallydisplayed on the remote 5-digit LED-type digital indicators on the cargo areaconsole. The Whessoe remote readout indicator is positioned adjacent.

The system automatically scans and prints the values of the selectedmeasurement. In addition, the data is converted to volumetric and mass measure,corrected for the ship’s list and trim based on manual and automatic inputs froma software configured to handle various functions.

The software configuration includes:

Manually input density data representative of the total cargo from a cargocomposition library stored in memory (up to 10 composition and densityvalues is available).

2 analogue inputs for list and trim

Volume expression in m3

Mass expression in tonnes

Custody transfer measurement takes place before and after loading anddischarging. During gauging, all cargo systems on the ship should be closedand the shore connections isolated or disconnected. No ballast operationsshould take place during measurement and the vessel should, if possible, be oneven keel and upright. However, the operation can be conducted with a slighttrim if the corrections included in the tank calibration tables are applied.

Custody transfer documents are produced detailing the volumes of cargo andvapour transferred during both loading and discharge operations.

Level MeasurementThe level measurement system consists of a long coaxial sensor installed in thetank and extends over the full depth in which the level is to be measured.

The liquid level is determined by measuring the electrical capacitance of thesensor segment intersecting the liquid level. The capacitance of this segment iscompared with the capacitance of a reference segment located below the liquidsurface. The ratio of these two measurements results in the accurate determi-nation of liquid level that is independent of liquid properties such as dielectricconstant, temperature and density.

This ratiometric method of cargo level measurement includes an innovativecalibration assurance feature incorporated to maintain the accuracy of the levelmeasuring sub-system; this system is called the ON-LINE Validation System.

The level measurement accomplished provides an accuracy of ± 7.5mm over theentire gauging height. The display resolution is 1mm at the system workstationand printer.

In the event of failure of the upper or lower segment or reference segment ofthe main column (used for determining level for loading and unloadingoperations) the fault is indicated on the VDU screen. If the EQUIPM screen isselected, equipment status may be displayed and the back-up devices selected.In the event of total failure of the CTS system, level sensing devices, theWhessoe Marine Liquid Level Gauge may be used for level measurementproviding that approval is given by the shore representatives.

The accuracy of the float gauge is the same as the capacitance gauge. The floatof the float gauge must be maintained blocked at the top position except whenduring the actual measurement.

The total gross number of cubic metres of cargo in the tanks before and afterloading or discharging is calculated using the average level readingdetermined. This volume is corrected for heel, trim, volume, vapour pressureand cargo and vapour temperatures.

The difference in these volumes at the start and end of the operation will betaken as the apparent volume (m3) of cargo delivered.

Temperature MeasurementTemperature measurement is accomplished by means of platinum resistancetransducers (500ohms) providing an accuracy of ± 0.2°C from -165°C to145°C, ± 0.3°C up to - 120°C and ± 1 - 5°C up to + 80°C.

Data is displayed at the system workstation and printer with a resolution of0.01°C.

There are five active and five spare temperature sensors in each tank and eachreading is recorded.

The determination of whether the temperature point is in vapour or liquid willbe made from the liquid level indication. It is safe to assume that any point thatindicates a temperature of more than 3° above the LNG temperature must bein the vapour space.

Although the temperature variation over the depth of liquid should be no morethan a fraction of a degree, the variation of vapour temperature, particularly atthe end of discharge, will be more pronounced.




SHIP'S NAME

<MEMBRANE>

[Attachment 4.2] to [Appendix DL-1]

CUSTODY TRANSFER DATABEFORE / AFTER LOADING/UNLOADING

CARGO NO

GAS OFFICER

DATE

TRIM

TEMP(DEG ºC)

TANK 1

TOP

95 % LEVEL

85 % LEVEL

50 % LEVEL

25 % LEVEL

BOTTOM

V

V/L

V/L

V/L

V/L

V/L

V

V/L

V/L

V/L

V/L

V/L

V

V/L

V/L

V/L

V/L

V/L

V

V/L

V/L

V/L

V/L

V/L

TANK 2 TANK 3 TANK 4 TOTAL/AVERAGE

METERS BY HEAD / STERN

VOYAGE NO

PORT NAME

TIME OFMEASUREMENTLIST DEGREES PORT / STARBOARD

ºC

ºC

AVERAGE VAPOR TEMPERATURE:

AVERAGE LIQUID TEMPERATURE:

VAPOR PRESSURE

AVERAGE VAPOR PRESSURE mb A / mmHg A

LEVELMEASUREMENT

(M)

LEVELCORRECTION

(M)

AVERAGE LEVEL (M)

1ST

2ND

3RD

4TH

5TH

TRIM

LIST

DENSITY

TAPE

CORRECTED LEVEL (M)

VOLUME (CUBIC M)

VOLUME SUMMED (CUBIC MAT _160.0 ºC)

DATE: COMPANY PRINT NAME SIGNATURE

SHIP'S MASTER:

BUYER'SREPRESENTATIVE:

TERMINAL'SREPRESENTATIVE:

SURVEYOR:

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

C/F

Shipping

SHIP'S NAME

<MEMBRANE>

[Attachment 5.2] to [Appendix DL-1]

CERTIFICATE OF LOADING / UNLOADING

CARGO NO.

TANK 1

AVERAGE LEVEL (M)

CORRECTED LEVEL (M)

VOLUME (CUBIC M)

VOLUME SUMMED

TANK 2 TANK 3 TANK 4

VOYAGE NO.

PORT NAME

INITIAL GAUGING

DATE

TRIM

AVERAGE LIQUID TEMPERATURE IMMEDIATELY BEFORE LOADING/UNLOADING:

AVERAGE VAPOR TEMPERATURE IMMEDIATELY BEFORE LOADING/UNLOADING:

AVERAGE VAPOR PRESSURE

METERS BY HEAD / STERN

TIME OF MEASUREMENT

LIST DEGREES PORT / STARBOARD

ºC

ºC

mb A / mmHg A

(CUBIC MAT _160.0 ºC) (A)

DATE: COMPANY PRINT NAME SIGNATURE

SHIP'S MASTER:

BUYER'SREPRESENTATIVE:

TERMINAL'SREPRESENTATIVE:

SURVEYOR:

Shipping

TANK 1

AVERAGE LEVEL (M)

CORRECTED LEVEL (M)

VOLUME (CUBIC M)

VOLUME SUMMED

TANK 2 TANK 3 TANK 4

FINAL GAUGING

AVERAGE LIQUID TEMPERATURE IMMEDIATELY BEFORE LOADING/UNLOADING:

AVERAGE VAPOR TEMPERATURE IMMEDIATELY BEFORE LOADING/UNLOADING:

AVERAGE VAPOR PRESSURE

VOLUME LOADED (B) - (A) / UNLOADED (A) - (B) (CUBIC M)

ºC

ºC

mb A / mmHg A

(CUBIC MAT _160.0 ºC) (B)

Illustration 4.8.1b Computer Cargo Record Sheets


Pressure MeasurementAbsolute pressure measurement in each of the cargo tanks is determined byintelligent pressure transmitters. The accuracy of the measurement is ± 0.1%of span to a resolution of 0.1kPa at system workstation and printer.

Range of measurement is 80.0 to 140.0kPa. Ambient temperature effect on thetransmitter is ± 0.2% per 55°C change between limits of -30°C and +60°C.

Independent Very High Level Alarm SystemTwo very high level alarms per tank are provided by independent point sensingelements. Fixed sensors inside the cargo tanks detect the cargo at predeter-mined levels and system accuracy is ± 6mm.

The very high alarm adjusted at 98.6% of the tank height when activated, willclose the corresponding tank filling valve.

The very very high alarm adjusted at 99% of the tank height when activated,will initiate an Emergency Shut Down alarm (ESD) (refer to Section 4.12.2).This involves the shutting of the manifold and tank loading valve of the tankin question. The IAS has facilities to inhibit at 98.6% and 99% to allowopening of the tank valve during the level alarm testing.

In addition, a blocking function is provided to allow all cargo tank level alarmsto be overridden when at sea.

Failure of CTS ComputerIf the computer should fail during custody transfer, it is usually still possible toread and record the individual level, temperature and signal readings from thelocal digital read-out panels otherwise the levels have to be measured using theWhessoe float gauges. The volume calculations and corrections have to bemade by hand using the hard copy of the tank gauge tables.

The cargo record report sheet is used in conjunction with the gauging tables,which contain the correction figures for trim, list, bottom fine gauging andthermal (level gauge) of each individual tank, to give the accurate values of thecargo CV, Btu, m3 and metric tons.

The ship’s trim, list, local tank gauge readings, average tank temperature,vapour space temperature, cargo specific gravity figures are required.

When the computer is back on-line it can be used in the manual mode toperform the level calculations.




Illustration 4.8.2a Whessoe Float Level Gauge

Local Level Indicator

Cushion Spring

CrankingHandle

Inspection Plate

Weather Deck

12" Gate Valve

Tank Ceiling

Barrier


4.8.2 Whessoe Float Level Gauge(see illustration 4.8.2a)

The Whessoe float level measurement system is of conventional tanker type,but uses an Invar tape to compensate for temperature variations.

A guagehead, containing a mechanical indicator, an Invar tape tensioned by anegator spring and a 12” diameter PV float attached to the lower end of thetape, is fitted to each liquid dome.

Two guide wires for the float are attached at the lower ends to an anchor bar130mm above the tank bottom, which is secured to the trellis structure baseplate. The sinkage of the float in LNG is 15mm and the minimum level whichcan be read from the gauge is 145mm.

! CautionTo reduce the risk of tape failure and wear on the gauging mechanism, thefloats should be fully stowed at all times, except when taking a sounding.Care should be taken when stowing the float as excessive tension maycause tape breakage. It is possible for a failed tape to foul the capacitancecolumn, resulting in the loss of gauging facilities for that tank.

To obtain the liquid level, the float is released from its stowage position usingthe release lever, and allowed to descend freely to the liquid surface. The tanksounding may then be read from the meter. The Whessoe gauges are checkedagainst the Foxboro CTS during each alternate loading.

The crank handle on the side of the gauging head is used to re-stow the floatinto the gauging head by turning the handle in the direction of the arrow asmarked. A close inspection of the counter should be maintained as the floatapproaches the top. When resistance of the float against the cushion spring isfelt, proceed with more care until the plunger shaft is positively secured by thelocking shaft.


Crack Handle

Release Lever

Purge Valve

Purge Connection

Level Indication


Issue: 1

4.8.3 Trim-List Indicator

The ship is provided with a fixed Trim-List Indicator system for the custodytransfer system.

Maker: Utsuki Keiki KK, Yokohama, JapanType: Detector CSM-2DD; Indicator TMW-4B and DVF-11ERange: ± 2m trim

± 5° listAccuracy: ± 0.5% FSDOutput: 4 to 20mA both channels

The detector is installed in the electric equipment room on C deck withindicators at the CACC cargo console and a repeater on the bridge console,starboard side. The measurement principle is that a suspended mass within theinclination detector moves from a centre position when the ship trim or listvaries. The movement is detected by linear variable differential transformercoils. A local circuit unit box converts this into a 4 to 20mA signal for eachaxis and these are fed to the CTS interface.

The detector is deck-mounted and contained inside a wooden box, the cover ofwhich is closed and has an official seal. The power on control box is mounteddirectly above.

As the response is set to 0.5s, the system cannot give reliable readings underway.

Alarm Settings

Trim: ≥ 3mList: ≥ 1.5°

The readings should be checked against draught marks in calm weatheralongside periodically.

(Note ! The IAS trim list measurements are derived from the MusasinoDraught System, and not this instrument.)

InclinationDetector

Port Stbd

Aft

Fwd

List Indicator

Electric Equipment Roomon C deck

CACC

Wheelhouse Console

Trim Indicator

List IndicatorTrim Indicator

Trim and ListSignals to CTS

220V AC

Circuit Unit BoxCB-2S

4.8 Custody Transfer System Page 7 of 7


Trim and List Indicator in the CACC

Inclination Detector in the ElectricalEquipment Room

Illustration 4.8.3a Trim-List Indicator

Issue: 1 4.9 Nitrogen Generator Page 1 of 2

PI

PI

DPI DPI DPITS

BufferTank24m3

10Bar

Key

Gaseous Nitrogen

Oxygen Enriched Air

F.W. L.T. Cooling

Air

Illustration 4.9a Nitrogen Generator

WF027

WF029

To BilgePrimary Tank




TI

WF026

WF028

TI

No.2 Feed AirCompressor

260Nm3/h at 12kg/cm2

No.1 Feed AirCompressor

260Nm3/h at 12kg/cm2 DPI DPI DPI

TAH

TIC TT PI TI

MIT

MAH

DIT

DAH

PS

Electric FeedAir Heater

TAH

DAHDAH

TS

TAH

TIC TT

Electric FeedAir Heater

TAH

PAL

PS

PAL

PITAH

PITAH

PSPSPT

PIAL

PIPT

PIAL

DAHH

PI TI

PI TI

MIT

MAH

DIT

DAH DAHDAH

DAHH

PI TI

N2 90m3/h Membrane

N2 90m3/h Membrane

10-5kg/cm2

9kg/cm2

10-5kg/cm2

CN006

Set

9kg/cm2

Nitrogen ToMain Cargo

Line

Nitrogen ForEngine Room

Services

Set

CN002

CN007

CN011

CN010

CN003

To Funnel


4.9 Nitrogen Production System

4.9.1 Nitrogen Production Plant

Two nitrogen generators, installed in the engine room, produce gaseousnitrogen which is used for the pressurisation of the barrier insulation spaces, asseal gas for the HD and LD compressors, fire extinguishing in the vent mastrisers and for purging of various parts of the cargo piping.

The two high capacity units (90Nm3/h each), are able to produce 180m3/h ofnitrogen, which is mainly required for the topping up of the barrier insulationspaces during loading, cooldown and other services, like vent mast fire extin-guishing and compressor sealing.

The operating principle is based on the hollow fibre membranes through whichcompressed air flows and is separated into oxygen and nitrogen. The oxygenis vented to the atmosphere via the engine funnel and the nitrogen stored in a24m3 buffer tank ready for use.

The high capacity units each consists of a Tamrotor FL45-13 screwcompressor, cooled from the LT fresh water cooling system, a single stageair/water separator, three air filters arranged in series, a 4kW electric heater,before passing into the membrane units. An oxygen analyser, after themembrane, monitors the oxygen content and, if out of range, above 5% O2,(although Gaz Transport recommend 3%) redirects the flow to the funnel.

The nitrogen is stored in a 24m3 buffer tank, where high and low servicepressure set points actuate the start and stopping of the generators.

High Capacity UnitManufacturer: Permea Maritime ProtectionNominal flow rate: 90Nm3/h + 90Nm3/h at 97% N2Delivery pressure: 8 barDew point: -70°COutlet gas composition: Oxygen 3% by volume

Carbon dioxide < 30 ppmNitrogen balance to 100%

Screw compressor:Tamrotor FL45-13: 306m3/hCompressed air atmembrane inlet: < 125 kPaMaximum back pressureO2 enriched air: 0.05 kPaNominal power: 52kWSystem operatingtemperature range: 0 to 35°C

Membrane inletoperating temperature: +50°COil residual content: < 0.003 ppmFiltration efficiency forparticles with size =0.01 micron: > 99.99%Dew point (with dryingcapability of membranes,final dew point will be < -55°C): -20°CFour independent time operated condensate drain valves.

Hollow fibre membrane unit with dry filters have the following characteristics(at 50°C inlet temperature) 90 + 90 Nm3/h, N2 97%, O2 residual 3%.

The membranes are provided with a back pressure control valve downstreamof a flow meter, which maintains a constant membrane pressure.

The nitrogen generators are equipped with an oxygen analyser, whichcontinually monitors the oxygen content in the nitrogen output. If the level ofoxygen rises above 1% of the design value, then an alarm is activated on theconsole. If the level of oxygen rises further then the high high alarm operates,redirecting the flow to atmosphere and closing the discharge line to the buffertank.

The gaseous nitrogen generators are operated automatically, locally or from theCACC via the IAS mimic C-14.

Control Systems and Instrumentation

The control panel permits fully automated unmanned operation of the units.The following alarms and controls are mounted on the control panels.

Pushbuttons for start/stop operation

System status indications

Pushbutton for audible alarm acknowledgement

Continuous N2 delivery pressure

Continuous O2 content reading

Dew point analyser

Electrical heater temperature control

Emergency stop pushbutton

Alarms and Shutdowns

Tag No. Description Set point

TAH-1A/B Air heater high temperature (system shutdown) 200°C

TAHH-2A/B Feed air high high temp. (system shutdown) 80°C

TAH-2A/B Feed air temperature high 65°C

MAH-1A/B Dew point level high -60°C

OAH-1A/B Oxygen content high 3.5%

OAHH-1A/B Oxygen content high high 4.0%

PAL-1A/B Feed air pressure low 700kPa g.

FAH-1A/B Nitrogen flow high 103Nm3/h

PAL-5 Nitrogen buffer tank pressure low 300 kPa g.

PAH-5 Nitrogen buffer tank pressure high 800 kPa g.

DPAH-1A/B Differential pressure high 0.08kPa g.

Oxygen Analyser

A fixed O2 content analyser is installed on the package units, which isconnected before the remotely operated three-way valve.

The analyser has the following characteristics, O2 range 0 to 25%, with anoutput signal of 4 to 20 mA for the remote indicator, alarm panel and threeway valve actuation.

Issue: 1 4.9 Nitrogen Generator Page 2 of 2


Nitrogen Control Panel and Filters in the Engine Room

Issue: 1 4.10 Inert Gas and Dry Air Generator Page 1 of 4

PI PI

TAH

TAH TI

PT PI PIC

PIC

DPT

FI

Illustration 4.10a Inert Gas and Dry Air System

Demister

ChillerUnit

WS302

WS336

WS335

Combustion Air

Light Diesel Oil

FW Cooling

Sea Water

Inert Gas

Chilled Water

Key

O2 Analyser

RefrigerationCompressor

and Evaporator

DesiccantVessel

UnitNo.1

DesiccantVessel

UnitNo.2

ZI

zs

To BilgeHolding Tank

LDO Supply toMain Burner and Igniter

Funnel DeckTo IG Main

From BallastPump Discharge

zs

zs

PT

TIIAS

TI

PT

PI

TT TI TAH

MAH MI

MS MI

TS

TI

TS

TAH

TSTSHL

TAHL

TI

TS

TAH

MAH

PIIASPT PI PAH

ZS

ZS

ZS

TAH

PAH

TI

PI

PS

PAHL

PS

PAHL

PS

PI

PAL

Dew PointAnalyser

ElectricHeater

Water Separator

Cooler

Steam Heater


4.10 Inert Gas and Dry Air Generator

General

The inert gas/dry air plant, installed in the engine room, produces dry air orinert gas which is used for the tank and piping treatments prior and after a drydocking or an inspection period. The plant is operated locally or from theCACC, with mimic C-15 used to monitor the system.

The operating principle is based on the combustion of a low sulphur contentfuel and the cleaning and drying of the exhaust gases.

The inert gas plant includes an inert gas generator, a scrubbing tower unit, twocentrifugal fans, an effluent water seal, a fuel injection unit, an intermediatedryer unit (refrigeration type), a final dryer unit (adsorption type) and aninstrumentation / control system.

Manufacturer: Kaverner MossType: LPI 2 x 100% blowersInert gas delivery rate: 14,000Nm3/hDry air delivery rate: 14,000Nm3/hDelivery pressure (bar g.): 0.25 at dryer outletInert gas/dry air dew point: -45°C at dryer outletInert gas composition O2:: 0.5% by volumeInert gas composition CO2: 14%Inert gas composition CO (max): 100ppmInert gas composition NOx (max): 65ppmInert gas composition SO2 (max): 2ppmNitrogen balance to 100%:Inert gas composition ‘soot’: Bacharach 0Gas outlet temperature: Normal +17°C max +50°C at dryer outlet

The dry air/inert gas plant is locally operated.

The connection to the cargo piping system (refer to 2.2.1a) is made throughtwo non-return valves and a spectacle blank which is in the normally closedposition, and the connection to the cargo compressor room is made through aremovable bend (not normally connected).

Working Principle

Inert gas is produced by the combustion of light diesel oil (LDO) supplied bythe fuel pump with air provided by blowers, in the combustion chamber of theinert gas generator.

Good combustion is essential for the production of a good quality, soot free,low oxygen inert gas.

The products of the combustion are mainly carbon dioxide, water and smallquantities of oxygen, carbon monoxide, sulphur oxides and hydrogen. The

nitrogen content is generally unchanged during the combustion process and theinert gas produced consists mainly of 85% nitrogen and 15% carbon dioxide.

Initially, the hot combustion gases produced are cooled indirectly in thecombustion chamber by a sea water jacket. Thereafter cooling of the gasesmainly occurs in the scrubber section of the generator where the sulphur oxides are washed out. The sea water for the IG generator is supplied by oneof the ballast pumps via ballast main isolating valve BA024. The sea waterflow into the scrubber section is adjusted on valve WS336.

Before delivery out of the IG generator, water droplets and trapped moistureare separated from the inert gases by a mist separator. Further removal of wateroccurs in the intermediate dryer stage, where the refrigeration unit cools thegas to a temperature of about 5°C. The bulk of the water in the gas condensesand is drained away with the gas leaving this stage via a mist separator. In thefinal stage, the water is removed by an absorption process in a dual vesseldesiccant dryer. The desiccant dryer units work on an automatic change overcycle, where the out of line desiccant unit is first reactivated with warm dry airwhich has gone through the reactivation dryer system.

A pressure control valve located at the outlet of the dryer unit maintains aconstant pressure throughout the system, thus ensuring a stable flame at thegenerator.

Dew point and oxygen content of the IG produced are permanently monitored.The oxygen level controls the ratio of the air/fuel mixture supplied to theburner. The oxygen content must be below 1% by volume and the dew pointup to a maximum of -65°C with a minimum of -55°C. Both parameters aredisplayed locally and remotely through the IAS.

For delivery of IG to the cargo system, two combined remote air-operatedcontrol valves operated through solenoid valves are fitted on the distributionsystem, i.e. the purge valve and the delivery valve.

Dry-Air ProductionThe IG generator can produce dry-air instead of IG with the same capacity.

However, for the production of dry-air:

There is no combustion in generator

There is no measure of oxygen content

The oxygen signal is overridden when the mode selector is on dry-airproduction

After the processes of cooling and drying, and if the dew point is correct, thedry air is supplied to the cargo system through the delivery valve (with thepurge valve closed).

Burner Description

The combustion air is supplied to the main burner by two ‘roots’ type blowers,each supplying 50% of the total capacity of the generator. The quantity ofcombustion air to the burner can be manually adjusted by a regulating valve inthe excess air discharge line.

LDO is supplied at a constant pressure by the fuel pump which has a built-inpressure overflow valve.

Before ignition or start up of the unit and with the pump running, all the fuelis pumped back via this fuel overflow valve which also serves to regulate thedelivery pressure of the pump.

The fuel flows to the nozzle of the main burner via two solenoid valves andtwo fuel regulating valves.

A programme switch in the local control panel regulates one of the solenoidvalves which also operates the pilot burner and initial firing.

The main burner is ignited by a pilot burner. The main fuel burner is of the highpressure atomizing type. The fuel is directed to the burner orifice throughtangential slots, which imparts a rotation motion ensuring that the fuel leavesthe burner as a thin rotating membrane which is atomized just after the nozzle.

Procedure for Operation of the Inert Gas System

Before the IG plant is put into automatic mode the following must take place.

a) Select and set up one ballast pump to supply sea water to thescrubber and cooling unit.

b) Ensure the POWER ON lamp is illuminated. It is important thatthe power supply is maintained on the IG unit in order that thealarm monitoring continues to function.

c) Any alarm condition on the system is must be reset via theALARM RESET button.

d) Check that the oxygen analyser calibration is correct.

e) Start the selected duty air blower.

f) Press the cooling plant AUTO START button h/s 111 and air dryerAUTO START button h/s 114 to initiate their start up.

The plant can now be started in auto mode.

g) Press the AUTO START button h/s 311.




PI PI

TAH

TAH TI

PT PI PIC

PIC

DPT

FI

Illustration 4.10a Inert Gas and Dry Air System

Demister

ChillerUnit

WS302

WS336

WS335

Combustion Air

Light Diesel Oil

FW Cooling

Sea Water

Inert Gas

Chilled Water

Key

O2 Analyser

RefrigerationCompressor

and Evaporator

DesiccantVessel

UnitNo.1

DesiccantVessel

UnitNo.2

ZI

zs

To BilgeHolding Tank

LDO Supply toMain Burner and Igniter

Funnel DeckTo IG Main

From BallastPump Discharge

zs

zs

PT

TIIAS

TI

PT

PI

TT TI TAH

MAH MI

MS MI

TS

TI

TS

TAH

TSTSHL

TAHL

TI

TS

TAH

MAH

PIIASPT PI PAH

ZS

ZS

ZS

TAH

PAH

TI

PI

PS

PAHL

PS

PAHL

PS

PI

PAL

Dew PointAnalyser

ElectricHeater

Water Separator

Cooler

Steam Heater



h) Ensure there is a flow through the bubbler unit for cleaning thesample gas.

i) Inspect the cooling jacket observation glass to ensure that all theair has been removed.

The plant will run through a start sequence which will be displayed via theindication lamps on the mimic board.

j) After the FLAME ON indication is illuminated and the plant isrunning at full capacity with an acceptable O2 content, check thefuel return pressure and temperatures.

Until the O2 content is within the acceptable limits, the gas will be led toatmosphere.

k) When the O2 content is stable and of an acceptable limit theSELECT CONSUMER can be activated, which will now deliverthe gas to the IG main.

Operating Procedure to Stop the Plant

a) The first step is to redirect the IG gas to atmosphere bydeselecting the SELECT CONSUMER button.

b) The STOP button can now be selected. The burner system willshut down but the SW valves will remain open and the blowerrunning for a preset cooldown period. After the SW valves haveshut the ballast pump can be shut down.

Instrument Description Alarm List for Cooling Plant h112 Set Point RemarksNumberMP55 LO Pressure Low 0.35MPaKP15 Compressor Suction Pressure Low 0.2MPaKP15 Compressor Suction Pressure High 2.15MPaKP98 High LO Temperature/ High R404A Discharge Temp. 80 / 120ºC4F10.1 Compressor Motor AlarmKP2 Cooling Water Inlet Condenser Pressure Low 50kPa

Instrument Description Alarm List for Drying Plant h113 Set Point RemarksNumberH9 Cycle Time Failure H13 Cooling Water Alarm High Gas Temp. Outlet Cooler 70ºCH14 Regeneration Inlet Temp. Too High 210ºCKP98 High LO Temperature/ High R404A Discharge Temp. 80 / 120ºC4F10.1 Compressor Motor AlarmKP2 Cooling Water Inlet Condenser Pressure Low 50kPa

Instrument Description Alarm List for Main Plant Set Point RemarksNumberAAHH204 O2 Content Very High 5.0%AAH204 O2 Content High 3.0%AAL204 O2 Content Low 0.3%H112 Cooling Plant Failure N/AH113 Drier Plant Failure N/AH135 Cooling Plant Running Failure N/AH117 Drier Plant Running Failure N/ATAH219 IG to Deck High 55ºCMAH270 IG Outlet Drier Dewpoint High -45ºCTAH198 IG Outlet Drier Temp. High 12ºCPAL-181-1 Blower No.1 Outlet Air Pressure Low 15kPaPAH-181-1 Blower No.1 Outlet Air Pressure High 100kPaPAL-181-2 Blower No.2 Outlet Air Pressure Low 15kPaPAH-181-2 Blower No.2 Outlet Air Pressure High 100kPaPAH182 IG to Consumer Pressure High 27kPaPAH214 Gas Outlet Cooling Tower Pressure High 50kPaPAL 183 Instrument Air Pressure Low 400kPaPAL184 Sea Water Supply Pressure Low 90kPaPAL185 Fuel Oil to Burner Pressure Low 1.7MPaTAH189 SW Outlet Scrubber Temp. High 55ºCTAH191 SW Cooling Jacket Temp. High 55ºCTAH192 Gas Outlet Scrubber Temp. High 55ºCBA200 Burner Flame FailureLAH193 SW in Scrubber Level HighH15 SW valve 15 to Bilge Not Open PositionH109-1 Blower No. 1 Motor Running FailureH109-2 Blower No. 2 Motor Running FailureH83 Fuel Oil Pump Motor Running FailureH129 SW Pump Motor Running FailureH300 24V AC Power Failure

Common IG Alarm to IAS


Issue: 1 4.11 Fixed Gas Detection System Page 1 of 2

Illustration 4.11a Fixed Gas Detection System

NDIR GasAnalyserFMA-3UR

0-100% LEL

NDIR GasAnalyserFMA-3UR

0-100 Vol %

100 Vol %N2

4 Vol %CH4

90 Vol %CH4

PA1

PA2

Calibration Gas Alarm Bottles

No.1 Cargo Tank InterBarrier Space (1)


No.1 Cargo Tank Insulation Space










No.1 Cargo Tank Cofferdam



AnalyserExhaust

Exhaust

Exhaust

Power Supply Box

Repeater Panel

Pilot Lamp Power Supply BoxAlarm (30%LEL)

Power Supply BoxAlarm (60%LEL)

Power Supply BoxFailure

%LEL Vol%

Lamp Test

No.1 Cargo TankIBS (1)


No.1 Cargo TankInsulation Space










No.1 Cargo TankCofferdam





Duct Keel No.1

Duct Keel No.2 Gas Vent Drain Tank

Cargo MachineryRoom (1)

Cargo MachineryRoom (2)

Cargo MachineryMotor Room (1)

Cargo MachineryMotor Room (2)

Bosun Store Fwd PumpRoom

Bow ThrustRoom

Under PassageWay Port (1)

Under PassageWay Port (2)

Under PassageWay Stbd (1)

Under PassageWay Stbd (2)

No.1 Cargo TankVent Mast




Cargo AreaFailure

Engine Room

Cargo Area

Cargo Area

E.R. SupplyFan No.1

E.R. SupplyFan No.2

E.R. SupplyFan No.3

E.R. SupplyFan No.4

E.R. 2ndDeck No.1

E.R. 2ndDeck No.2

E.R. ExhaustFan No.1

E.R. ExhaustFan No.1

EmergencyGen Room

Engine RoomFailure

PassageS-Upp Deck

PassageP-A Deck

PassageS-A Deck

PassageP-B Deck

Cargo MachneryRoom 1

Cargo MachneryRoom 2

Cargo MachneryMotor Room 1

Cargo MachneryMotor Room 2

PassageS-B Deck

PassageP-C Deck

PassageS-C Deck

PassageP-D Deck

PassageS-D Deck

AccommodationFailure

BOG Pipe Duct

Gas PipeDuct No.1

Gas PipeDuct No.2

Gas PipeDuct No.3

Boiler GasHood

Inert Gas LineAfter Dryer

Engine Sub Con Room (ESCR)

Gas PipeDuct No.1

Gas PipeDuct No.2

Gas PipeDuct No.3

Boiler GasHood

Inert Gas LineAfter Dryer

Engine Sub Con Room (ESCR)

BOG Pipe DuctFailure

Accommodation

Wheel House CACC Cargo Office Ship's Office Lecture Room Officer'sMess Room

Crew's Mess Room

Officer'sRec Room

Crew'sRec Room

Galley A/C AirIntake 2

A/C AirIntake 1

PassageP-Upp Deck


4.11 Fixed Gas Detection System(see illustration 4.11a)

There are two means of monitoring gas detection throughout the ship, thiscovers all the cargo, machinery and accommodation spaces. The infrared gasanalyser system monitors the cargo areas and BOG lines, while the machineryand accommodation is monitored by the catalytic combustion method. Alarmindication is shown in the CACC on the IAS system, mimic C-18 covers thecargo areas, with specific LEL % figures given for each tank liquid and gasdomes, while C-89 covers the BOG hood area and C-90 covers the accommo-dation.

Infrared Gas Analyser System

The principle of operation of the Komyo gas analyser is based on the infraredadsorption characteristics of methane gas. The sampling analyser unit islocated in the electrical equipment room on C deck.

Samples for analysis (a mixture of methane and nitrogen), are drawn throughsmall bore lines from the sample points, which are as follows;

Cargo Area SystemSample point Location

1 No.1 cargo tank interbarrier space (1)2 No.1 cargo tank interbarrier space (2)3 No.1 cargo tank insulation space4 No.2 cargo tank interbarrier space (1)5 No.2 cargo tank interbarrier space (2)6 No.2 cargo tank insulation space7 No.3 cargo tank interbarrier space (1)8 No.3 cargo tank interbarrier space (2)9 No.3 cargo tank insulation space10 No.4 cargo tank interbarrier space (1)11 No.4 cargo tank interbarrier space (2)12 No.4 cargo tank insulation space13 No.1 cargo tank cofferdam14 No.2 cargo tank cofferdam15 No.3 cargo tank cofferdam16 No.4 cargo tank cofferdam17 No.5 cargo tank cofferdam18 Duct keel (1)19 Duct keel (2)20 Gas vent drain tank21 Cargo machinery room (1)22 Cargo machinery room (2)23 Cargo machinery motor room (1)24 Cargo machinery motor room (2)25 Bosun store26 Forward pump room27 Bow thruster room

28 Under passage way port (1)29 Under passage way port (2)30 Under passage way starboard (1)31 Under passage way starboard (2)32 No.1 cargo tank vent mast 33 No.2 cargo tank vent mast 34 No.3 cargo tank vent mast 35 No.4 cargo tank vent mast

To ensure a representative sample is monitored each time a space is sampled,each space is continuously drawn.

Each sample line has two two-way solenoids, which are operated sequentiallyby the control unit. One of the sample lines is connected to the sampling pump(PA1) manifold, while the other line is connected to the continuously drawpump (PA2) on the bypass manifold. The bypass line pump discharges thesamples not being analysed directly to atmosphere, while the sampling pumpdischarges the gas through the analysing unit before being discharged toatmosphere. As each point is being analysed the corresponding indicator lightsup, each point is analysed for approximately 45 seconds.

The analyser works on the principle that infrared light is absorbed by themethane gas. Methane gas has a distinctive absorption band in the infraredspectrum. Therefore if a sample of gas is compared against a reference sampleof air, the difference in output from an infrared sensor will be in proportion tothe gas concentration.

If the methane concentration of any sample point reaches 30% LEL, an audiblealarm is sounded in the CACC and the corresponding indicator lamp is lit.Additionally a gas detection alarm is activated on the bridge and in the ESCRon their respective repeater panels.

Sample points 21, 22, 23, and 24 are also monitored up to 60% LEL at whichpoint the trip system is activated.

Boil-off Gas Pipe DuctSample point Location

1 Gas pipe duct No.12 Gas pipe duct No.23 Gas pipe duct No.34 Boiler gas hood5 Inert gas line after dryer6 ESCR

The boil-off gas pipe duct samples are continuously monitored by its ownsampling analyser. The alarm is initiated at 30% LEL, and if the gas concen-tration continues to rise to 60% LEL the trip signal is activated.

The gas analyser’s zero should be checked daily and the span checked weekly.

Catalytic Combustion Analyser System

The system monitors the atmosphere continuously at the points where sensingheads are fitted, and will detect presence of any combustible gas. They arefitted where gas could accumulate. The sensors provide electrical outputs, pro-portional to the amount of gas present, to alarm and indicating units in theCACC, ESCR and wheelhouse.

Engine Room SystemSample point Location

1 Engine room supply fan No.12 Engine room supply fan No.23 Engine room supply fan No.34 Engine room supply fan No.45 Engine room 2nd deck No.16 Engine room 2nd deck No.27 Engine room exhaust fan No.18 Engine room exhaust fan No.29 Emergency generator room

Accommodation SystemSample point Location

1 Wheelhouse2 CACC3 Cargo office4 Ship’s office5 Lecture room6 Officers’ mess room7 Crew’s mess room8 Officers’ recreation room9 Crew’s recreation room10 Galley11 Spare12 Fresh air intake air conditioning 13 Passage port upper deck14 Passage starboard upper deck15 Passage port A deck16 Passage starboard A deck17 Passage port B deck18 Passage starboard B deck19 Passage port C deck20 Passage starboard C deck21 Passage port D deck22 Passage starboard D deck

All the above spaces activate the alarm at 30% LEL.

For full details refer to the Komyo gas detection operating manual.

Issue: 1 4.11 Fixed Gas Detection System Page 2 of 2


Issue: 1 4.12 Cargo and Ballast Control Valve Emergency Shut Down System Page 1 of 11

H

H

No.7 Sol.Valve Box

CG915

H H H H H H

CG533 CG533 CG533 CG533 CG533 CG533

H H H

CL401 CL402 CL403

H

CS356

H H H H H

CS450 CS451 CS452 CS454 CS455

H

CS456

H

CS754

H

CG920

H H H H H H

CL012 CL022 CL032 CG072 CL042 CS750

H H H H H H

CL011 CL021 CL031 CG071 CL041 CG079

H H H H

CS351 CS352 CS354 CL355

H H

CL303 CS350

H H

CL301 CL302

H H H

CS252 CS254 CS255

H H H

CL203 CS250 CL251 CS256

H H

CL201 CL202

H H

H

CL200 CL210

H H H

CS150 CS154 CS155

H H H

CS151 CS152 CL156

H H

CL101 CL102

H H

CL103 CL100

H

CL400

H H

CL300 CL310

H H

CL410 CG773

H

CG901

H

CG900

H

CG904

H

CG907

H

CG910 CG913

H

CL100

H

CG771

Power PackFor Cargo Valves

Acc. StandFor Power Unit

For Cargo Vlaves

No.1 Sol.Valve BoxNo.2 Sol.

Valve BoxNo.6 Sol.Valve Box

No.5 Sol.Valve Box

No.3 Sol.Valve Box

No.4 Sol.Valve Box

No.8 Sol.Valve Box

Engine Room

Trunk Deck Trunk Deck

Manifolds (Port)

Trunk Deck Trunk Deck

To/From Power Unit

(For Ballast)

H

CG875

Side Passage

Side Passage

Illustration 4.12.1a Cargo Valve Hydraulic Lines


4.12 Cargo and Ballast Valve Control and Emergency Shut DownSystem

4.12.1 Cargo and Ballast Control System

General Description

All the valves necessary for the operation of the cargo and ballast system arehydraulically operated by separate hydraulic power packs, situated in theengine room, 3rd deck port side forward. Control of the power packs (mimicC-10) and valve operation is from the IAS mimic and key board situated in theCACC.

Cargo System

The hydraulic power unit consists of two main pumps and one topping-uppump. During normal loading and unloading operations, only one pump isrequired to meet the demand, while the second pump is put on automaticstandby cut in mode and will cut in when the system pressure is reduced to9.8MPa. The topping up pump is normally used during forcing vaporizationoperations.

All remotely operated valves are piston operated except for the liquid domevalves and valve CS750, which are vane type actuators. The supply oil isdistributed to 8 solenoid valve cabinets situated along the trunk deck. Eachcargo tank, manifold area, cargo machinery room and the master BOG stationhas its respective solenoid cabinet as follows:

No.1 solenoid cabinet feeds No.1 cargo tankValves CL110, 100, CG771 piston type (butterfly)Valves CS156, 151, 152, 150, 155, 154, CL101, 102, 103 vane type (globe)

No.2 solenoid cabinet feeds No.2 cargo tankValves CL210, 200 piston type (butterfly)Valves CS256, 251, 252, 250, 255, 254, CL201, 202, 203 vane type (globe)

No.3 solenoid cabinet feeds No.3 cargo tankValves CL310, 300 piston type (butterfly)Valves CS356, 351, 352, 350, 355, 354, CL301, 302, 303 vane type (globe)

No.4 solenoid cabinet feeds No.4 cargo tankValves CL410, 400, CG773 piston type (butterfly)Valves CS754, 456, 451, 452, 450, 455, 454, CL401, 402, 403 vane type (globe)

No.5 solenoid cabinet feeds the starboard manifold (ESDS)Valves CL012, 022, 032, 042, CG072 piston type (butterfly)Valves CS750 vane type (globe) not ESDS40 litre accumulator with a 7.8MPa nitrogen pressurised bladderDistribution block to ESDS valves

No.6 solenoid cabinet feeds port manifold (ESDS)Valves CL011, 021, 031, 041, CG071 piston type (butterfly)Valves CG079 piston type (butterfly) not ESDS40 litre accumulator with a 7.8MPa nitrogen pressurised bladderDistribution block to ESDS valves

No.7 solenoid cabinet feeds cargo machinery roomValves CG900 piston type (butterfly)Valves CG907, 910, 901, 904, 913, 915, 920 vane type (globe)

No.8 solenoid cabinet feeds BOG master valve (ESDS)Valve CG875 piston type (butterfly)10 litre accumulator with a 7.8MPa nitrogen pressurised bladder

Initiation of an ESDS signal will operate solenoid valves ESDS 1, 2 and 3,thereby porting hydraulic oil onto the ESDS valves. An accumulator is fittedto each ESDS section, in order that in the event of a power pack failure it isstill possible to shut the valves.

Hydraulic Power Pack Cargo

The unit consists of a 1,000 litre oil tank, with the two main and one toppingup pumps situated on top of the tank. Suction is through 150 micron filters,before passing onto the main rail through individual non-return valves. Thereis a bank of four accumulators of 60 litre capacity each, pressurised to 7.8MPawith nitrogen. Each accumulator has a drain valve, in order to drain down tothe main tank if required. The system is protected by 2 safety relief valves setat 13.7MPa, which return to the tank via the main return line. There are nopump discharge line filters apart from the individual 10 micro paper filtersfitted at each solenoid cabinet station.

Pressure switches control the pump cut in/cut out, with low oil pressure alarmand pump failure alarms transmitted to the IAS. The oil level in the tank ismonitored by a low level alarm switch, operated at 700 litres and a low lowlevel pump cut out switch, operated at 500 litres. The system return has two 10micron paper filters arranged in parallel, with individual isolation valves. Oneof the filters is kept off line. The filters have a differential pressure alarm fittedwhich is activated at 240kPa.

Pump SettingsPump cut in 10.8MPaPump cut out 12.7MPaStandby pump cut in 9.8MPaHigh pressure alarm 13.2MPaLow pressure alarm 8.8MPaESDS operating pressure 8.3MPaRelief valve 13.7MPa

Emergency Hand Pump Operation

All the cargo hydraulic piston type operating valves have an emergency handpump connection. There are two portable emergency hand pump units, oneavailable on deck and one in the duct keel space for use on the ballast tankvalves. The isolating valves on the distribution block are first shut off and thehoses of the emergency hand pump fitted to the snap-on connectors. Control ofdirection is via a hand operated changeover control block. The capacity of thesump tank is 4.2 litres.

Operation

a) Check that the emergency hand pump has the sump tank toppedup to the correct working level.

b) On the cylinder to be operated, isolate the hydraulic supply andreturn valves.

c) Fit the flexible hose snap-on connectors.

d) Shut the hand pump unloading valve.

e) Operate the direction control valve lever to give the desiredmovement of the cylinder.

f) Operate the hand pump until the valve has reached the desiredposition (visually or feed back from the limit switches). Theemergency hand pump can now be disconnected after firstrelieving the pressure on the hoses by opening the pumpunloading valve.




H

FD577

H H

OF503 OD551H H

BA016 BA020

H H

BA013 BA007

H H

BA002 BA003

H H

BA017 BA021

H

BA524

H H

OF012

H H

WS002 WS101

H H

BA030 WS001

H H

BA026 BA029

WS421

H

FD042

H

OD010

H

FD548

H

FD549

HH H H

HH

WS102

OF532 OF532 OF510 OF502

WS023 WS131 WS420

H H

H

OF015

H

OF013

H

OF002

H

OF004

H

BA110

H

BA508

H

BA025

H

BA015

H

BA027

H

BA009

H

BA522

H

BA520

H

BA521

H

BA523

H

BA032

H

BA031

H

BA501

H

H H

BA513 BA515

H H

BA509 BA511

H

BA514

H

BA512

H

BA505

H

BA502

H

BA504

H

OF001

H

BA503

H

BA507

H

BA506

H

BA011

H

BA006

H

BA014

H

BA028

H

H H

BA517 BA519

H

BA518

H

BA516

No.2 Sol. Valve BoardFor Ballast, Bilge, FOSW Cooling System,Water Spray System.

Power PackFor Ballast, FO

& Ship Side Valves

No.1 Sol. Valve Board for

Ship Side Valve

Acc. StandFor Power Unit

For Ballast

Engine Room

Pipe Duct

Boson Store

Upper DeckIllustration 4.12.1b Ballast Valve Hydraulic Lines

No 4 W.B Tank (Port)

No 4 W.B Tank (Stb'd) No 3 W.B Tank (Stb'd) No 2 W.B Tank (Stb'd) No 1 W.B Tank (Stb'd)

No 3 W.B Tank (Port) No 2 W.B Tank (Port) No 1W.B Tank (Port)

H.F.O Tank (Fwd)

F.P Tank

Fwd Deep W.B Tank(Port and Stb'd)

H

BA001

H

BA008

H

BA010

H

BA012

OF501


Ballast, Fuel Oil and Ship Side Valves System

The hydraulic power unit consists of two main pumps and one topping-uppump. During normal operations, only one pump is required to meet thedemand, while the second pump is put on automatic standby cut-in mode andwill cut in when the system pressure is reduced to 9.8MPa. The topping uppump is normally used to maintain the system pressure outside of generaloperations.

All remotely operated valves are piston operated. The supply oil is distributedto two solenoid valve cabinets situated in the engine room. The operation ofthe valves is conducted from the IAS in the CACC.

The ship side valves supplied from No.1 solenoid cabinet may be operatedfrom their local position and also from the fire control centre, in addition tooperation from the IAS in the CACC.

No.1 Solenoid Cabinet Valves

Solenoid No. Description Valve No.1 Low sea suction centre WS0012 High sea water suction starboard WS0023 Low sea water suction starboard WS1014 High sea water suction port WS1025 Atmospheric condenser overboard WS0236 IG generator overboard WS3027 Port ballast overboard BA0268 Starboard ballast overboard BA0299 Central cooler overboard WS13110 Ballast eductor overboard BA03011 Scoop inlet valve WS42012 Main condenser overboard WS421

The following valves are operated from No.2 solenoid cabinet;

Ballast SystemBA006, 011, 014, 028, 017, 021, 001, 008, 031, 032, 002, 003, 010, 012, 013,007, 015, 025, 027, 009, 016, 020, 502, 503, 504, 508, 509, 512, 513, 516, 517,520, 521, 505, 524, 506, 507, 510, 511, 514, 515, 518, 519, 522, 523

Fuel System; HFO, DO and LDOOF013, 015, 002, 004, 012, 501, 532, 533, 510, 502, 503. OD551, 010FD042, 548, 549

Hydraulic Power Pack Cargo

The unit consists of a 650 litre oil tank, with the two main and one topping uppumps situated on top of the tank. Suction is through 150 micron filters, beforepassing onto the main rail through individual non-return valves. There are twoaccumulators of 60 litres capacity each, pressurised to 7.8MPa with nitrogen.Each accumulator has a drain valve, in order to drain down to the main tank ifrequired. The system is protected by two safety relief valves set at 13.7MPa,which return to the tank via the main return line. There are no pump dischargeline filters apart from the individual 10 micro paper filters fitted at eachsolenoid cabinet station.

Pressure switches control the pump cut-in/cut-out, with low oil pressure alarmand pump failure alarms transmitted to the IAS. The oil level in the tank ismonitored by a low level alarm switch, operated at 400 litres and a low lowlevel pump cut out switch, operated at 350 litres. The system return has two 10micron paper filters arranged in parallel, with individual isolation valves. Oneof the filters is kept off line. The filters have a differential pressure alarm fittedwhich is activated at 240kPa.

Pump SettingsPump cut in 10.8MPaPump cut out 12.7MPaStandby pump cut in 9.8MPaHigh pressure alarm 13.2MPaLow pressure alarm 8.8MPaRelief valve 13.7MPa

The ballast, FO and ship side hydraulic system can be used as an emergencyback-up supply to the main cargo valve system, by opening two isolating crossconnecting valves which must be kept shut in normal use.

Emergency Hand Pump Operation

All the hydraulic piston type operating valves have an emergency hand pumpconnection. There are two portable emergency hand pump units, one availablein the engine room and one in the duct keel space for use on the ballast tankvalves. The isolating valves on the distribution block are first shut off and thehoses of the emergency hand pump fitted to the snap-on connectors. Control ofdirection is via a hand operated changeover control block. The capacity of thesump tank is 4.2 litres.

Operation

a) Check that the emergency hand pump has the sump tank toppedup to the correct working level.

b) On the cylinder to be operated, isolate the hydraulic supply andreturn valves.

c) Fit the flexible hose snap-on connectors.

d) Shut the hand pump unloading valve.

e) Operate the direction control valve lever to give the desiredmovement of the cylinder.

f) Operate the hand pump until the valve has reached the desiredposition (visually or feed back from the limit switches). Theemergency hand pump can now be disconnected after firstrelieving the pressure on the hoses by opening the pumpunloading valve.




ESDSTest

Test Switch(CACC)

Reset Switch(CACC)

Cancel Switch(CACC)

Override Switch(CTS)

Manual Switch

Fusible Plug(I.S)

Pressure Switch(I.S)

Pressure Switch

Press. Switch

I.S TypeSensor

I.S TypeSensor

I.S TypeSensor

Switch Board

Manual Switch(I.S)

ESDSReset

ESDSCancel

EmergencyShut Down

Control

Tank Level Very High andTank Level Extremely High

Override

Manual Switch

Fire(Fusible Plug Melted)

Pneumatic Pressure Lowin Ship/Shore Connection

Control AirPressure Low

Cargo Tank LevelExtremely High

Electrical PowerFail

Hydraulic OilPressure Low

Cargo Tank PressureLow

Cargo Tank LevelVery High

Intrinsically SafeBarrier

(Solenoid Control)

Alarm EventPrinter

IAS

Alarm

(Cause Indication)

PC(Interlock)

No.6 SolenoidValve Box Shore Connection Valve (Port)

Shore Connection Valve (Starb

Cargo Pump

Spray Pump

No.5 SolenoidValve Box

CargoSwitchboard

CargoSwitchboard

CargoSwitchboard

I.G.G ControlPanel

SolenoidValve Box

SolenoidValve Box

Ship / ShorePneumatic Hose

Air Release

ESDS Fail(Self Diagnosis)ESDS

Signal

Tank ProtectionControl 1

Tank ProtectionControl 2

ESDSFrom / To Shore

ESDSFrom / To Shore

ESDS To Shore

Electrical ConnectorInterface

OpticalInterface

PneumaticInterface

CTSPanel

CTSPanel

IAS

Intrinsically SafeBarrier (Signal)

ESDS

ESDS

ESDS TPS 1

Emergency Cargo PumpESDS

Emergency Shut Down System

Interlock Operation

Normal Operation

Tank Protection System 1

Tank Protection System 2

TPS 1

IGG Blower

ESDS

ESDS

TPS 1

Tank Filling Valve

BOG Master Valve

Air Release Magnetic Valve

TPS 2

ESDS TPS 1

HD Compressor

LD Compressor

ESDS TPS 1

ESDS TPS 1

I.S Barrier and ESDS Control Panel

I.S Barrier Panel

TankProtection 1

Signal

TankProtection 2

Signal

Electric Signal Optical Signal Air Signal

To CACC Console

OR

Illustration 4.12.2a Emergency Shutdown and Cargo Tank Protection Scheme


4.12.2 Emergency Shutdown and Cargo Tank Protection Scheme

In the event of fire or other emergency condition, the entire cargo system, gascompressors and master boil-off gas isolating valve to the engine room may beshut down by a single control.

Shut down of the cargo system is actuated either manually or automatically byfire or certain off limit conditions.

Description (see illustration 4.12.2a)

The manual emergency controls are located as follows:

CACC

Wheelhouse

Fire control station

Each tank liquid dome (4 units, one at each dome)

Forward area

Cargo machinery motor room

Cargo machinery room

Port and starboard manifold platforms (one each side)

Automatic shutdown for fire is controlled by nine fusible plugs located asfollows:

Each tank liquid dome (four units, one at each dome)

Cargo machinery motor room (one unit)

Cargo machinery room (two units)

Port and starboard manifold platforms (one each side)

There are three ESDS interface connections made to the shore facility, ie.electrical, visual and pneumatic. In port, the visual link and pneumatic systemswill inform the shore of any ship’s ESDS actuation and will stop the loadingor discharge pumps and close the shore liquid valves. The electrical link ismainly for redundancy back-up.

Automatic shutdown occurs when any of the following conditions occurs:

Vapour header pressure falls to within 0.3kPa of atmosphericpressure

Vapour header pressure falls to primary insulation space headerpressure

Each tank pressure falls to within 0.5kPa of the insulation barrierspace pressure

Each tank pressure falls to the insulation space pressure

Very high liquid level (99%) in any tank

Automatic shutdown for fire

Shutdown signal from the terminal

Initiation of an ESDS signal will operate solenoid valves ESDS 1, 2 and 3,thereby porting hydraulic oil onto the ESDS valves. An accumulator is fittedto each ESDS section so that in the event of a power pack failure it is stillpossible to shut the valves. The cargo pumps including the stripping/spraypumps are shut down. The fusible plugs are fitted into the pneumatic controlair line, whereby on melting, the pressure drop on the control is detected whichhas a five second time delay before a signal is sent to the ESDS system. Thefusible plug is designed to melt at between 98-104ºC.

! CautionBefore using the blocking switch, determine exactly what has caused theshutdown.

Before using the blocking switch, turn the controls for all crossover valvesto the shut position.

Use the blocking switch when absolutely necessary to recover from anemergency condition.

When the emergency condition is corrected, immediately restore theshutdown system to normal.



ESDS Fusible Plug Unit No.8 Solenoid Cabinet in Passageway Port Side,Showing Hydraulic ESDS Accumulator


From Mooring Tension Monitor Computer

MooringLoad

MonitorModem

PublicPhone

PlantPhone

HotLine

Phone

From Mooring Load Monitor Display

MooringLoad

MonitorModem

PublicPhone

Ship'sExch.

Phones

HotLine

Phone

Multiplex UnitElectrical/Optical

Interface

Multiplex UnitElectrical/Optical

InterfacePort/Stb'd Section

EmergencyShutdown Unit

With E/O Interface

EmergencyShutdown Unit

With E/O Interface

Power Supply UnitControl Alarm

Module

Power Supply UnitControl Alarm

Module

Yuken Plant EmergencyShutdown Control System

Yuken Plant EmergencyShutdown Control System

Tel I/FUnit

Tel I/FUnit

Tel I/FUnit

Tel I/FUnit

SpareSpares

Shore Side

Shore Side OpticalCable Reel50 - 100m

Ship Side

Starboard SideShip Connector

Shore SideConnector

Port SideShip Connector

Illustration 4.12.3a Ship-Shore Optic Fibre Transmission and ESD Link System Schematic

Optic/Electric

Mux

FurukawaOptical

TransmissionPanel

Earth BondingConnector (Not Used)

Earth BondingConnector (Not Used)

NotebookPC

Strainatall

YewmacMooringTensionMonitor

Yewmac PCModem

ModemIS BarrierPanel

HotlineTelephoneArun BontangRas Laffan

Indonesia

Other

Optical

Electrical

Mooring Tension MonitorP'Yeong TaekInchon

ESDP'Yeong TaekInchonBintulu

PABX & Hotline TelephoneBintuluPABX, Public & Hotline TelephoneP'Yeong TaekInchon

Public TelephoneHotline Telephone

PABX, Public & Hotline TelephoneOmanESDOman

CACC

HotlineTelephone

InchonP'Yeong Taek

CACC PublicTelephone

PABXTelephone

Key

Pyle National

Strainstall

Miyaki

Furukawa Optic

ITT Cannon

P

S

M

F

IC

Telecomms

Fibre Optics

Data

ESD

YukenESDS System

P

P

F F

M

M

S S

M

M

M

M

P

P

Electric Equipment Room

Accommodation Upper Deck

Port Side Manifold Starboard Side Manifold


4.12.3 Ship Shore Link

Linked ship to shore emergency shutdown systems have been required bySIGGTO since the early days of LNG loading and discharge installations. Theyminimise the consequences of an accident, or if abnormal conditions arise,they allow the process to be shut down with minimum spillage of liquid. Thusconsequent risk to jetty and ships’ structures and escape of flammable vapouris avoided.

Since both ship and shore exchange liquid and vapour, the shipside andshoreside Emergency Shutdown (ESD) must be linked. This is to avoid:

Excessive surge pressure on the loading arm connection causing damage the upstream valve is closed first

Overfilling ship or shore tanksRisk of damage or spillage due to excessive movement of shipwith respect to berth

In addition to the safety requirement for ESD, the ship to shore link has beenextended to handle communications by telephone.

The ship-shore links are implemented on this ship as follows:

Electrical Systems - Explosion-Proof (Ex’d’) Miyaki type

Three 6-way Miyaki connectors designed for Zone 1, Div II, temp rise T4 arefitted port and starboard. These are for use with:

P’yeong Taek, Inchon and Bintulu Ship/shore and shore/ship ESD

P’yeong Taek, Inchon and Bintulu Hotline, PABX telephone and publictelephone

Electrical Systems -Explosion-Proof (Ex’d’) Pyle National ConnectorType

A 37-way Pyle National Connector system for Oman is fitted port andstarboard. The main protection is made by a single explosion-proof connectorfor both IS ESD and non-IS telephone circuits. These circuits are mixed in asingle multicore cable.

! WARNINGFour way earth bonding connectors are provided but not used due toISGOTT regulations prohibiting their use.

Electrical Systems - Non-Certified ITT-Cannon Type

A 13-way ITT Cannon MIL-Std connector is fitted port and starboard outsidethe accommodation on upper deck, these are for use with:

Arun and Bontang Ship/shore and shore/ship ESD, hotline, PABX telephone

A selector switch in the CACC (Indonesia-Other) is used to switch the hotlinetelephone used for Arun/Bontang and Ras Laffan between the connectors.

Fibre Optic System - FurukawaUsing fibre optic technology, this system is inherently safe as fibre optic corescannot supply incendive energy. The fibre optic/electrical interfaces areinstalled in the electric equipment room on C deck. This system uses 2 x 6 wayfibre optic connector port and starboard and flexible cable to connect ship andshore. Freedom from external interference is inherently guaranteed. The fibre-optic cable is rugged and as long as the mating surfaces of the connector arekept clean, it gives few problems.

Compatible fibreoptic ship to shore ESD systems are installed in

Inchon 1

P’yeong Taek 1 and 2

Bintulu 1 and 2

Bontang

Ras Laffan 1 and 2

Oman

The main features of the systems are:

Two cores dedicated to a ship/shore and a separate shore/ship emergencyshutdown giving instantaneous optic system response of less than 10ms.

A second pair of cores dedicated to ship/shore and shore/ship communications. Four channels are supported, usually, these are:

Channel 1 1200 baud modem data path for the YEWMAC mooring tension monitor

Channel 2 Public telephone

Channel 3 Ship exchange phone (PABX)

Channel 4 Dial-less call-phone (inter-phone)

Two further spare cores at present are installed but not used.

The communication multiplex system uses low carrier frequencies (18 kHz to114 kHz) with bandwidths of only 3.4 kHz, amplitude modulated.

The ESD system uses 5 kHz and 10 kHz tones to signal normal safe andnormal ESD operation with tone loss or out of range operation triggering anabnormal fail-safe ESD.

Operating Procedure of the Fibre Optic System Test

a) A selector switch on the CACC panel selects either the OPTICALor ELECTRIC systems.

b) Pushbuttons on the fibre optic panel in the electric equipmentroom select either the PORT or STB’D connector.

c) Testing is by loopback connector. This is to be fitted to either portor starboard connection box to test transmit to receive paths.

d) When the loopback connector is fitted the ESD red LED andyellow ABNORMAL LED will be extinguished and the greenNORMAL LED will be lit.

e) Press TEST. The four yellow ABNORMAL channel LEDs willbe extinguished and the four green NORMAL LEDs will be lit.

(Note ! This is designed to test the fibre optic paths for signal presence only.For ESD signals, the ESD function can be tested. For telephone signals, thespeech path is not tested, but the transmit and receive circuits are tested bypushing the TEST pushbutton. If the paths are OK, the four green NORMALLEDs light.)

Alarms and ShutdownsTag No. IAS Description

System Abnormal

Pneumatic Systems

Two quick-connect male/female umbilical pneumatic connectors are providedat main deck level underneath the manifolds for use with the similar systemsused at Ras Laffan and other terminals. These directly trip the loading valveson pressure loss and are sensed by the Yuken ESD system.




Loading PlatformBD-2A BD-2B BD-2C

MD-2EMD-2D

3 Stern Lines

3 Breast Lines3 Breast Lines

3 Head Lines

2 Springs2 Springs

M8

M7

M6

M5

M4

W1

W2

M1M2

M3

MD-2CMD-2BMD-2A

Loading PlatformBD-4 BD-3 BD-2 BD-1

MD-1

MD-2MD-3MD-4MD-5

MD-6

MS

TUG POINTTUG POINT TUG POINT TUG POINT TUG POINTTUG POINT

TUG POINT TUG POINT TUG POINT TUG POINTTUG POINT

INCHON (Port Alongside) - Mooring Layout

3 Stern Lines

4 Breast Lines 4 Breast Lines

3 Head Lines2 Springs 2 Springs

M8

M7

M6

M5

M4

W1

W2

M1M2

M3



Qatar No.2 (Port Alongside) - Mooring Layout

Key:

Winch/ Windlass Controller

EmergencyEmergencyStopStop

EmergencyStop

StartStartStart

Illustration 4.12.4a Mooring Load Monitor System

Chain PaidChain PaidOut MeterOut MeterChain PaidOut Meter

EmergencyEmergencyStopStop

EmergencyStop


4.12.4 Mooring Load Monitoring System

Winches

Spool specification and performance.

The low pressure hydraulic mooring winches and combined windlass/mooringwinches are fitted with split spools designed to handle either a synthetic softrope of 80 mm diameter or a steel wire rope of 36 mm diameter. The spools aredesigned to take four layers of soft rope and five layers of wire. The spools aresplit into a storage and a working area to avoid the wire becoming buried in thestowed layers. Operators should ensure at least three turns have been placed onthe working section before applying a load. Failure to comply with this willlead to rapid deterioration in wire condition.

Spool diameter: 576 mmStorage length: 720 mmWorking length: 400 mm

First Layer PerformanceRated speed under load (245kN): 15 m/min rated speed no load30 m/min brake rendering stress : 716 kN drum end diameter 600 mmLength: 700mm

Precautions before using.

a) Check the correct function of clutches, gear change mechanismand safety contacts. Equipment should operate smoothly withoutundue effort being applied.

b) Checkthat the brakes are free to operate and that the bands releaseevenly from all contact areas.

c) Check the heave in and pay out controls for correct function.

Controls should return to the neutral position when released.

d) Verify that all lubrication routines have been carried out.

e) Check hydraulic feeder lines for signs of leakage.

Operating Procedure

The drum end is keyed directly on to the drive shaft and always turns wheneverthe winch is in use.

Personnel and loose gear should be kept well clear. To use the drum end,ensure that the wire spool has been taken out of gear and the brake applied.

Smoothly and slowly adjust the heave in or pay out control until the desiredoperating speed is achieved. To cease heaving, return the control to the neutralposition. Whenever a winch is in use, a clear view of the overall task in handis essential. If the winch operator cannot clearly see the entire operation fromthe control position then a responsible man must be positioned to guide him.

Internationally recognised signals for the visual guidance of winch operatorscan be found in the Code of Safe Working Practice for Merchant Seaman.

Mooring winches are each fitted with two wire spools. Only one spool can besafely operated at any one time. Under no circumstances should both spools ora spool and drum end be operated simultaneously.

a) Ensure both spools are out of gear and the brake applied to each.

b) Gently operate the heave in or pay out control to align the dogclutch with the selected spool.

c) Stop the winch and engage the clutch. Remove the spool brakeand operate winch as previously described.

! WARNINGNever attempt to engage a clutch with the drive shaft rotating.

Sunken Bitts

The ship is provided with 18 sunken bitts 4.8m above the loaded and lightshipcondition waterline respectively.

The SWL is 150 tonnes.

Mooring Load Monitor (MLM) System

The terminals at which the ship berths are normally fitted with MLM systems.These include quick release mooring hooks which have load cells whichmonitor the mooring line tension accurately.

The analysis of tensions is carried out by a shore-based computer. In each case,the shore system relays data to the shipboard repeater and displays graphicallythe tensions on a screen in the CACC.

Yokugawa YEWMAC SystemThe Yokugawa YEWMAC data is transmitted via channel 1 of the fibre opticESD ship shore link system. See section 4.13.4.

The computer in the CACC, when switched on, will display the load data fromshore and no operator input is required.

Strainstall SystemThis uses a notebook PC in the CACC and a modem. Data is transmitted fromthe shore computer via EX’ia’ intrinsically safe interfaces and a connectormidships. See section 4.13.4.

Operating Procedure - Strainstall System

The RUN SCREEN page is automatically displayed on the monitor. Thisshows the mooring configuration, alarm limits and loads applied.

When starting the software, the MLM program runs under Windows 95. Theprogram is started by double-clicking on the SES icon in the Program RepeaterGroup. LOAD NEW JETTY can be used to select previously installed jettyconfiguration.

Trending is available.

Diagnostics via the serial ( COM ) port is available.


Terminal System RepeaterP'yeong Taek Strainstall Ltd InstalledInchon Strainstall Ltd InstalledOman Marimatech a/s Carried on boardBintulu Yokugawa YEWMAC InstalledArun Yokugawa YEWMAC InstalledQatar Yokugawa YEWMAC InstalledBontang Yokugawa YEWMAC Installed



Loading PlatformBD-1 BD-2 BD-3 BD-4

MD-6MD-1

MD-5MD-2

3 Head Lines

4 Breast Lines

3 Stern Lines

4 Breast Lines

2 Springs 2 Springs

M8

M7

M6

M5

M4

W1

W2

M1 M2

M3

MD-3 MD-4



P'yeong-Teak No.1 (Starboard Alongside) - Mooring Layout

Key:

Winch/ Windlass Controller

Illustration 4.12.4b Mooring Load Monitor System


4.13 Total Boil-Off Gas Control System

General Description

Heat transfer to the liquid cargo due to temperature differentials between theinsulation spaces and the cargo tanks will cause the liquid to boil and vapourto be formed. This development of vapour is termed the cargo tank boil-off andit must be removed in order to maintain equilibrium within the tanks at thedesigned operating pressure. The volume of boil-off is also increased onpassage due to the energy dissipated by the agitation of the cargo caused by themotion of the ship.

Gas normally taken from the main gas header, is compressed using the LDcompressor(s) and is then heated in the fuel gas heater before being deliveredto the boilers.

Control System

The BOG control system is manufactured by Kawasaki Heavy Industries andis integrated into the IAS system.

Cargo Tank Pressure ControlThe system monitors the vapour header pressure in absolute and gauge mode.The operator must first select the correct voyage mode in which the controllersshould operate on the IAS as follows:

Mode Voyage Pressure Sensor Cargo Tank PressureCondition Mode Selection Control Mode

1 Laden Absolute Absolute controlfor Laden

2 Laden Gauge Gauge controlfor Laden

3 Ballast Gauge Gauge conditionfor Ballast

In this manner the sensors will collect and calculate the appropriate data for thecontrollers to operate.

The function of the sensors is to give the following signals:

Available gas flow from cargo tank, for the control of the forcingvaporizer flow control

Excess BOG dump signal for the boiler steam dump control

Set point and process value for the vent mast control

Vent Mast Control

Vent mast valve CG771 is controlled from the IAS and has three control levelsas follows;

Cargo tank protection

Manual vent inhibit

Vent control at Vent Mode

In the cargo tank protection mode, the vent mast valve CG771 will open to fullflow (100% capacity) when a pressure on the vapour header exceeds the setvalue PVH1. The valve will stay in this mode until the pressure registered onthe vapour header drops below PVH2, at which point the valve will close. Inthe cargo tank protection mode, the manual vent inhibit and vent control at ventmode is disabled and manual operation of the vent valve is not available.

In the manual vent inhibit mode, the vent valve will stay closed while theengine telegraph is in astern or if in the wheelhouse the vent inhibit order is inoperation. In this mode the manual operation of the vent mast valve is notavailable. The cargo tank protection mode will override the manual ventinhibit.

In the vent mode, the IAS controls the opening of the vent mast valve CG771according to the vapour header pressure, while BOG is being routed to theengine room for burning in the boilers. In this mode the manual operation ofthe vent mast valve is not available.

Boil-Off Gas Heaters

Via the IAS, the outlet temperature of the BOG through the boil-off heaters ismonitored, with the temperature at the outlet from the heater being regulatedby the activation of the heater inlet valve and heater bypass valve. Manualoperation of the control valves is not available while control is from the IAS,although the manual operation of the output of the PID controller is available.

Under boil-off heater trip conditions the IAS will automatically close the heaterinlet valve and open the bypass valve. Both valves will be locked in this modeuntil the trip condition is recovered. The boiler controller will receive a signalfrom the IAS of the heater trip and order a changeover to FO burning only.

Forcing Vaporizer

The IAS monitors the BOG flow rate and outlet temperature from the forcingvaporizer and sets the control valves on the forcing vaporizer accordingly.

There are three modes at which the forcing vaporizer is operated:

Manual mode

Sequence manual mode

Sequence cascade mode

In manual mode, the control parameters are set locally by the operator for BOGflow and temperature.

In sequence manual mode no manual operation of the flow control valve isallowed. Output is equalised to a setting of the preset value of flow controlvalve opening as defined by NNAF. In this mode it is possible to transfer to themanual operator mode.

The sequence cascade mode does not allow any intervention by the operatorapart from being able to select a mode transfer. In this mode, the demand fromthe boiler and the cargo tank pressure are matched automatically.

LD Compressor Control

The LD compressors receive a control signal corresponding to the fuel gascontrol valve position and the vapour header pressure, which acts upon the inletvain guides position and regulates the output from the LD compressoraccordingly in order to give the optimum output as demanded.

Issue: 1 4.13 Total Boil-Off Gas Control System Page 1 of 1


Issue: 1 4.14 Relief Systems Page 1 of 2

ManualVent Valve

Illustration 4.14.1a Cargo Tank Relief Valve

Illustration 4.14.3a Cargo Line Relief Valve

Illustration 4.14.2a IS/IBS Relief Valves

Diaphragm

To Atmosphereat Top of Vent Mast

Sensing Line

Easing Gear

To Vent Mast

Diaphragm

ManualVent Valve


4.14 Relief Systems

General Description

Each cargo tank is fitted with two pressure/vacuum relief valves as required bythe IMO code. The IBS and IS spaces are each protected by two pressure reliefvalves per cargo tank. The valves are manufactured by Luceat and are designedspecifically to work on marine based LNG systems.

4.14.1 Cargo Tank Relief Valves(see illustration 4.14.1a)

Manufacturer: LuceatType: PORV EXPON 10’’ x 12”Number of units: 8 plus 1 spareNumber per tank: 2

Setting:Overpressure: 25kPa gaugeFlow rate per valve: 24,538 Nm3/h

Vacuum relieving: -1kPa gaugeFlow rate per valve: 4,302 Nm3/h

The cargo tank relief valves are fitted at the liquid domes of each tank and ventto their associated vent mast riser. The relief valves are of the PORV (pilotoperated relief valve) type. A cargo tank pressure sensing line relays thepressure directly to the pilot operating valve, in this manner, accurate operationat low pressures prevailing inside the tank are assured.

The cargo relief valves are set up initially by the manufacturer for the require-ments on the ship. If overhaul of the valves by ship’s staff is carried out, thevalves must be checked and reset to the original settings. (See manufacturer’sinstructions for details.)

It is extremely important that the vent mast is checked on a regular basis anddrained of any accumulation of water. The purpose of this is to ensure that therelief valves operate at their correct settings which would otherwise be alteredif any water were to accumulate in the vent mast and flow onto the valveassembly.

4.14.2 IBS and IS Relief Valves(see illustration 4.14.2a)

Manufacturer: LuceatType: PORV R1101 2’’Number of units: 16 plus 1 spare

Number per tankIBS space: 2IS space: 2

Setting:Overpressure: IBS: 3.0kPa gauge IS: 3.5kPa gaugeFlow rate per valve: IBS: 289 Nm3/h IS: 318 Nm3/h

The IBS/IS spaces are protected by four PORV relief valves per cargo tank.The liquid dome and vapour dome each have one relief valve for the IBS andIS space that surrounds them. (See illustration 4.14.2b.)

A gas detection line is lead out from below each of the valves to the gasmonitoring system to give a constant indication of the atmosphere inside theIBS and IS spaces.

The IBS relief valve vapour outlet is led to a separate vent line, which runs upalongside the associated vent mast. This is in order to prevent any counterpressure or back flow from the main vent mast should the cargo tank reliefvalves lift, or from the nitrogen snuffing system.

It is extremely important the vent line is checked on a regular basis and drainedof any accumulation of water. The purpose of this is to ensure that the reliefvalves operate at their correct settings which would otherwise be altered if anywater were to accumulate in the vent mast and flow onto the valve assembly. The IS space relief valves vent directly to deck, via a downward facing tailpipe. It is not necessary for these to be led to a mast riser as the likelihood ofthere being LNG vapour in the insulation space is very remote.

The IBS/IS valves are set up initially by the manufacturer for the requirementson the ship. If overhaul of the valves by ship’s staff is carried out, the valvesmust be checked and reset to the original settings. (See manufacturer’s instruc-tions for details.)

4.14.3 Line Relief Valves

Each section of the cargo pipe work that can be isolated by two valves has anoverpressure relief valve fitted. The cargo manifold relief lines release back toNo.2 liquid dome and the cargo machinery space relief lines release back toNo.3 liquid dome.

Manufacturer: SapagType: 8100 - 8200Setting overpressure: 1,000kPa gauge

Issue: 1 4.14 Relief Systems Page 2 of 2

Liquid Dome

Illustration 4.14.2b IBS / IS Relief Valve Layout

Vent Mast

IBS NitrogenExhaustControl

IS NitrogenExhaustControl

IBS VentMast

SweepingValve

To GasDetector

To GasDetector

Inter Barrier Space

Inter Barrier Space

Insulation Space

Insulation Space

IS NitrogenControl

IBS NitrogenControl

From NitrogenInsulation Pressurisation

Header

Vapour Dome

SweepingValve

To GasDetector


Line Relief Valve

Issue: 1 4.15 Ballast Level and Draught Gauging System Page 1 of 6

From WaterSpray Pump From No.2

Bilge, Fire andGS Pump

From No.1Bilge, Fire and

GS Pump

BA501

Fore PeakTank

BosunStore

BA502

BA504BA509BA511BA515BA519BA523

BA032BA012

BA013

BA009

BA010

BA002

BA003

BA006

BA011

BA027

BA025

BA025

To I.G.Generator

WS118

WS117

BA014No.3 Ballast Pump

3,000m3/h

No.2 Ballast Pump3,000m3/h


Self Priming

BA026

BA029

BA031

BA513BA517BA5021

BA508BA510BA514BA518BA522 BA512BA516BA520 BA503

Key

Sea Water Ballast

Sea Water Ballast Stripping

Ballast TankNo. 4 Port




Ballast TankNo. 4 Stbd




ForwardBallast TankStarboard

ForwardBallast Tank

Port

Illustration 4.15.1a Ballast Piping

Hydraulic Line

BA507

BA506

BA505WS172

BA001

BA008BA524

BilgeSuction

From PipeDuct

BA023

No.2 Eductor300m3/h

No.1 Eductor300m3/h

BA015

BA007

BA004

Emergency BilgeSuction

Sea WaterCrossoverStarboard

Low Suction

Sea WaterCrossoverPort HighSuction

BA017

BA021

BA019

BA030

FD032 FD010 FD020

BA028

To/FromAft Peak

Tank

To Main CSWSystem For

Emergency Use

To AuxiliaryCSW System

For Emergency Use Auto Stop by SequenceControl Signal

Auto Stop by SequenceControl Signal


BA020

BA016

PI PT PI

PI PT PI

PI

PI

LS ZI

LS ZI

LS ZI

PI

PI

PI PIPSPT

PI PIPSPT

PI PIPSPT

PI PT PI

PT

LIAH

BA12LIAH

BA10LIAH

BA08LIAH

BA06LIAH

BA09LIAH

BA11LIAH

BA07LIAH

BA05LIAH

BA04LIAH

BA03LIAH

BA02LIAH


4.15 Ballast Level and Draught Gauging System

4.15.1 Ballast Piping (see illustration 4.15.1a)

Description

The ballast spaces beneath and around the outboard side of the cargo tanks areutilised as ballast tanks to optimise draught, trim and heel during the variousload conditions of the vessel.

Ballast will be carried during the return passage to the loading port, when onlysufficient gas is carried to maintain the tanks and their insulation at cryogenictemperatures.

The ballast spaces are divided into 8 tanks, that is port and starboard undereach of the 4 cargo tanks. In addition, the fore peak water ballast tank and aftpeak tank are also used to carry ballast when required. This gives a total ballastcapacity of 54,074m3, approximately 55,426 tonnes when filled with sea water.

Three, 3,000m3/h, vertical centrifugal pumps are fitted, which enable the totalballast capacity to be discharged or loaded in approximately 24 hours usingone pump, or 12 hours using the three pumps. The pumps are driven by electricmotors and are located on the engine room floor, starboard side forward.

The 650 mm fore and aft ballast main runs through the duct keel with tankvalves mounted on tank bulkheads. The 250mm stripping main also runsthough the duct keel on the starboard side, this is connected to the strippingeductors.

The ballast pumps fill and empty the tanks via the port and starboard side650mm main.

Stripping and final educting is done using the water spray pump as the drivingwater for the eductor on the 250mm stripping main. The fire, bilge and GSpumps can also supply the driving water if required. The stripping linedischarges through its own overboard valve BA030 on the port side.

The forward water ballast tank space can also be filled and emptied using theballast mains. The crossover valve BA505 between the two mains is in theforward ballast tank.

All ballast pipes are of GRP with galvanised steel bulkhead pieces and suctionbellmouths.

All valves are butterfly valves hydraulically operated. The tank main suctionsand pump discharge valves are of the intermediate position controlled type.

System Capacities and RatingsMake: ShinkoType: Vertical, single stage centrifugalNo. of sets: 3Model: GVD500 -2MRated output: 3,000m3/h at 35m headSpeed: 900 rpm

Two ballast eductors: Each rated at 300m3/h

The pumps take their suction from the sea/sea crossover, with the high seasuction being on the port side and the low sea suction being on the starboardside. The latter is the normal operation when loading ballast. When dischargingballast they take their suction from the ballast crossover main.

The ballast pumps are used to supply sea water to the inert gas generatorsystem.

No.1 ballast pump has an emergency direct bilge suction from the engine roombilge, via valve BA004, which is operated locally from an extended spindle.This pump is of the self-priming type.

System ControlThe ballast system is controlled entirely from the CACC using the IAS inconjunction with the ballast mimics C-7, C-8 with operator guidance C-85, C-86.

The ballast pumps are started and stopped using the mimics, provided that theswitches on the MSB group starter panel are set to remote. The pumps have aauto stop sequence control for low and high tank status. When on local control,the pumps can be started and stopped from the local control panel, and can bestopped from this panel regardless of the position of the local/remote switch.The local control panels always take priority and can take control from theCACC at any time.

All hydraulically operated valves in the system are also operated using the on-screen menu/keyboard in conjunction with the ballast mimic. Two basic types ofvalve are fitted, those which can be positioned at the fully closed position or fullyopen, and those which can be positioned at any point between fully open andfully closed. The position of all valves is shown on the mimic. Provision is madefor a portable hand pump to be used to operate each valve in the event ofhydraulic accumulator failure. The pump discharge valves and the main tanksuction valves are multi-positional. All other valves are either open or closed. Inaddition to being operable from the CACC, the valves can also be operated fromthe hydraulic power station, using the pushbuttons on the individual solenoids.

The on-screen ballast menu also shows when the pumps are switched toremote, the pump’s suction and discharge pressure, the position of themanually operated valves and the level in each tank, in terms of inage.

Control and Alarm Settings

Setting Description

25m Fore peak tank level high

2m Fore peak tank level low

25m No.1 port ballast tank level high

2m No.1 port ballast tank level low

25m No.1 starboard ballast tank level high

2m No.1 starboard ballast tank level low






2m No.3 port ballast tank level lo



25m No.4 port ballast tank level hig




25m Forward port ballast tank level high

2m Forward port ballast tank level low

25m Forward starboard ballast tank level high

2m Forward starboard ballast tank level low




Illustration 4.15.2a Remote Sounding SystemHazardous Area Non Hazardous Area

Cable Pipe

Upper Deck

Float Arrangementin Water Ballast Tanks,

No.1 to No.4 Wings

Musasino Tank LevelGauging

Reed Switch Contacts

CACC

A

B

C

To ControlBox

SwitchClosed

Magnet

GuidePole

Zener Barrier Boxand Control

(Located in ElectricalEquipment Room)

Signal Inputs

To CACC Cargo Console

Float

Remote Indication On CACC Cargo Console Area


4.15.2 Remote Sounding System

(see P265)Maker: Musasino Co Ltd.Sensors: Type M-LZM

This is a float type gauging system incorporating a high level alarm operatingat 95% of tank capacity. The alarms are indicated at the cargo control consoleand both digital and analogue gauging outputs are available.

The level master detector at the top of the tank outputs its signal to zenerbarriers which act as the interface between the hazardous area and the non-hazardous area. From the barriers, the signal goes to the control box in theelectrical equipment room on C deck for interpretation and forwarding to thevarious display units.

Confirm the measurements with manual gauging. The bottom 200 mm of thetank depth cannot be measured with this system, as manual gauging must beused to verify that the tank is empty after discharge.

Remote sounding of the ship’s ballast, FW, FO, LO, atmospheric drain andrelevant bilge holding tanks, is via the Masasino system of magnetic floatsrising and falling up a support column. The column has a series of reedswitches and resistors arranged as a potentiometer at intervals of 2cm. As afloat magnet rises up the column, the reed switches adjacent to the floatconnect the centre connection to the resistor chain. The level can therefore bedetermined by the voltage from the centre connection with respect to thecommon connection of the element. Head mounted electronics convert thevoltage from the potentiometer into a 4 to 20mA signal which is transmitted toa control box in the electric equipment room.

The eight ballast tanks and forward HFO storage tanks are located in ahazardous area. The signal from these tanks are led to the control box in theelectric equipment room via zener barriers.

The ballast system tank signals are transmitted to the cargo I/O cabinet, withan anologue and digital display on the CACC cargo console. The remainingtank soundings are led to the machinery I/O cabinet. Only the main turbine LOsump indication has an anologue and digital display on the CACC machineryconsole.




Illustration 4.15.3a Draught Gauging System

Water Level

Sea WaterInlet

Float

Ships Side Valve

Magnet

FloatStopper

Cable Gland Disposal Point

Cable Pipe Aft

Port

Starboard

Control Box

Forward

CableGland

TerminalBox

UpperDeck

Air Vent

No.4 CargoTank

No.3 CargoTank

No.2 CargoTank

No.1 CargoTank

No.4 CargoTank

No.3 CargoTank

No.2 CargoTank

No.1 CargoTank

H.F.O.DeepTank

Engine Room

EngineRoom

Aft

Port

Starboard

Fwd.

27.650m 7.850m

LBP = 266.0m

Wheelhouse

CACC

Schematic

Level Master Detector

Reed Switch Contacts

A

B

C

To ControlBox

SwitchClosed

Magnet

GuidePole

Float

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0

m

LEVEL

FLOAT LEVEL %

UP DOWN

MODE 1 1 ENT

100

80

60

40

20

0


4.15.3 Draught Gauging System

Maker: Musasino Co Ltd.Sensors: Type M-LZM

The Musasino system is based on a tubular measuring element installed in a34mm column. The column is installed in a 250mm stilling well. The columnhas a series of reed switches and resistors arranged as a potentiometer atintervals of 2cm. As a float magnet rises up the column, the reed switchesadjacent to the float connect the centre connection to the resistor chain. Thelevel can therefore be determined by the voltage from the centre connectionwith respect to the common connection of the element. Head mountedelectronics convert the voltage from the potentiometer into a 4-20mA signalwhich is transmitted to a control box in the electrical equipment room. FourLED displays are provided on the consoles in the CACC and on the bridge togive indication of the draughts forward, aft, port and starboard.

The draught sensors are arranged so that the lower column is connected to thesea via a ship side valve at its lower measurement point. The uppermeasurement point is connected to another upper column in order to extend themeasurement range. Adjustment is made during the setting up of the sensorsso that the sensors read the draught at the marks under normal load conditions.If the ship is subject to extremes of heel and trim the readings will notaccurately reflect the readings at the draught marks. The aft peak tank onlycontains two columns, while the fore peak and the midships sensors are madeup of four columns each.

There is no damping in the system, so that in rough conditions even at theberth, these readings will fluctuate.

The forward and aft column arrangements are several metres from the forwardand aft perpendiculars of the ship and the forward draught marks are distantfrom the forward perpendiculars.

The port and starboard sensors are each located in a hazardous area. The signalfrom these is connected to Musasino intrinsic safety zener barriers installedwithin the control box.

The system is calibrated for sea water of density 1.025 tonnes/m3, a small errormay be introduced if the ship lies in fresh water.

A 4-20mA analogue output signals to the IAS system for each channel are alsoprovided.



Draught Indicators in the CACC

Part 5Cargo Auxiliary and Deck Systems

Issue: 1 5.1 Temperature Monitoring System Page 1 of 2

Illustration 5.1b Temperature Monitoring System Points in Cofferdam

StarboardStarboard Port Port

Aft Bulkhead

TICF10 (No.4)

TICF413 (No.4)

TICF112 (No.1)TICF210 (No.2)TICF310 (No.3)TICF410 (No.4)



7TE

10TE

8TE

9TE

11TE

Forward Bulkhead

TICF107 (No.1)

TICF110 (No.1)




12TE

15TE

13TE

14TE

16TE


5.1 Temperature Monitoring System

General Description(See illustration 5.1a)

Monitoring equipment is provided in the CACC for IS barrier and inner hulltemperatures to give warning in case of failure of insulation or leakage of IBSbarrier.

Each sensor is of PT 100 resistance type. The sensors are installed in the ISbarriers and alongside the inner hull associated with each cargo tank. Thetemperature range of each sensor is : -170°C to +50°C.

The IS barrier thermocouples (sensors) are installed at 6 points around thespace as shown, all 6 of them in pairs. During normal conditions, one thermo-couple is in service whilst the other is on standby. If the first sensor fails, thesecond will automatically come into service.

For the inner hull temperature measurement there are 5 sensors in each tank, 3are located along the bottom of the tank in the duct keel, while 2 sensors arelocated in the trunk deck.

In the cofferdam spaces there are 3 temperature sensors on each of the forwardand aft bulkheads, except the forward bulkhead of No.1 cofferdam which has5 sensors and the aft bulkhead of No.5 cofferdam which also has 5 sensors.(See illustration 5.1b.)

The temperature measurements are indicated for each thermocouple in servicein the CACC via the IAS. Recording of these temperatures is also available viathe IAS.

The thermocouples for the IS barrier sensors alarm point is set at -120°C.The thermocouples for the inner hull sensors alarm point is set at 0°C.

Issue: 1 5.1 Temperature Monitoring System Page 2 of 2

Illustration 5.1a Temperature Monitoring System

Starboard Port

TE 1A/1BTE 19

TE 18

TE 17

TE 21

TE 20

TE 3A/3B

TE 4A/4B

TE 5A/5B

TE 6A/6B

TE 2A/2B

Key

Interbarrier Space

Inner Hull

Interbarrier SpaceTemperature C

TE 1A/1B Bottom Aft Centre TE 2A/2B Bottom Centre TE 3A/3B Starboard Lower TE 4A/4B Starboard Mid TE 5A/5B Starboard Upper TE 6A/6B Centre Top

Inner Hull Temperature C TE 17 Forward Centre TE 18 Bottom Centre TE 19 Bottom Aft TE 20 Top Centre TE 21 Top Forward

°

°


Issue: 1 5.2 IBS/IS Nitrogen Pressurisation and Control System Page 1 of 2

Liquid Dome

Illustration 5.2a Nitrogen Pressurisation and Control System

Vent Mast

IBS NitrogenExhaustControl

IS NitrogenExhaustControl

IBS VentMast

SweepingValve

To GasDetector

Nitrogen

Key

To GasDetector

Pressure TransmitterBox per Vapour Dome

Pressure TransmitterBox per Liquid Dome

Inter Barrier SpaceInter Barrier Space

Insulation Space

CNn052

CNn054

CNn055

CNn056

CNn057

CNnv802

Nitrogen BufferTank 24m3

CNn003

To Engine RoomNitrogen Service

CNnv007

CNn010

CNnv011

CNn801

To HD and LDCompressorShaft Sealing

To HD and LDCompressor

Bulkhead Shaft Sealing

CNn051

Insulation Space

IS NitrogenControl

From NitrogenBuffer Tank

IBS NitrogenControl

To Spray Line

Insulation Pressurisation Header Control

Purging and Sealing Header

Vapour Dome

SweepingValve

To GasDetector

CNn002 CNnv006

10kg/cm2 / 5kg/cm2

9kg/cm2

9kg/cm2

10kg/cm2 / 5kg/cm2

PT PIPALIAS

PIIAS

PIN63

PIN61

XBN65

PIN62

FIN01

PICN82

PCCN81

XBN64

PT PIPS

Flow Meter

Start/StopSystem No.1

PS

PI

PIIAS

PALIAS

PAHIAS

PALIAS

FIIAS

PIIAS

PAL PAH

CNn053

PT PALIAS

PAHIAS

PACIAS

PIIAS

PIPT

PIPT PI

PIPT

TE

FI

DTP

PIISn5

DPIIBSn1

PIIBSn1PCIBSn0

PCIBSn8

DPCISn4PAHIAS

DPIIAS

DPALIAS

PAHIAS

PAHIAS

PAHIAS

PALIAS

PAHIAS

PALIAS

PIPT

PIPT

DPIDPI

PIIAS

PIIAS

PT

PCIBSn3C

DPCISn7C

Start/StopSystem No.2


5.2 IBS/IS Nitrogen Pressurisation and Control System

Nitrogen produced by generators and stored in a pressurised buffer tank issupplied to the pressurisation headers through make-up regulating valves.

From the headers, branches are led to the interbarrier and insulation spaces ofeach tank. Excess nitrogen is vented through regulating relief valves to thenitrogen vent mast on each tank from the IBS and to deck from the IS.

Both IBS and IS of each tank are provided with pressure relief valves whichopen at a pressure sensed in each space, of 3.0 kPa for the IBS and 3.5 kPa forthe IS above atmospheric. A manual bypass with a globe valve is provided forlocal venting and sweeping of a space if required.

The nitrogen production plant is maintained in an automatic mode. One 90m3/hpackage is able to maintain the pressure in the buffer tank owing to the smalldemands placed upon the system. When a high nitrogen demand is detected,the second 90m3/h package will start automatically.

Control Systems and Instrumentation

The control panel permits fully automated unmanned operation of the units.The following alarms and controls are mounted on the control panels:

Pushbuttons for start/stop operation

System status indications

Pushbutton for audible alarm acknowledgement

Continuous N2 delivery pressure

Continuous O2 content reading

Dew point analyser

Electrical heater temperature control

Emergency stop pushbutton

Inter-barrier and Insulation Spaces

The inlet and outlet control valves for both spaces at each cargo tank areoperated under split range control by the output of the reverse acting pressurecontroller for that space. Thus, when the pressure in that space falls below thedesired value, the inlet valve opens and the outlet valve remains shut. Whenthe pressure in the space rises above the desired value, the outlet valve opensand the inlet value remains shut.

The barrier space header control valve CN055 reacts to the demand on thesystem and maintains the header pressure at 50kPa. A flow meter upstream ofCN055 gives an indication on the IAS of the current demand on the nitrogensystem.

Pressure switches on the nitrogen buffer tank control the cut-in/cut-out of thecompressors via control panel 5.1A/B. Under normal operation, onecompressor is selected as run, with the second compressor on automaticstandby cut-in.

High/low and differential pressure alarms are fitted to the pressure controlsystems for each interbarrier and insulation space.

Nitrogen Generation Alarms and Shutdowns

Tag No. Description Set pointTAH-1A/B Air heater high temperature (System shut down) 200°CTAHH-2A/B Feed air high high temp. (System shut down) 80°CTAH-2A/B Feed air temperature high 65°CMAH-1A/B Dew point level high -60°COAH-1A/B Oxygen content high 3.5%OAHH-1A/B Oxygen content high high 4.0%PAL-1A/B Feed air pressure low 700kPa g.FAH-1A/B Nitrogen flow high 103Nm3/hPAL-5 Nitrogen buffer tank pressure low 300 kPa g.PAH-5 Nitrogen buffer tank pressure high 800 kPa g.DPAH-1A/B Differential pressure high 0.08kPa g.

Barrier Space Header and IBS/IS Alarms

Tag No. Description Set pointPCIBS10 No.1 cargo tank IBS pressurePIIBS11 No.1 cargo tank IBS pressure high/low 1.3 / 0.2 kPaDPIIBS11 No.1 cargo tank IS/IBS differential pressure h/l 1.2 / 0.0 kPaPIIS15 No.1 cargo tank IS pressure high/low 2.5 / 0.3 kPaPCCN81 IS/IBS header pressure 50 kPaPICN82 IS/IBS header pressure high / low 70 / 20 kPaFIN01 Nitrogen to barrier space total flow

PCIBS20 No.2 cargo tank IBS pressurePIIBS21 No.2 cargo tank IBS pressure high/low 1.3 / 0.2 kPaDPIIBS21 No.2 cargo tank IS/IBS differential pressure h/l 1.2 / 0.0 kPaPIIS25 No.2 cargo tank IS pressure high/low 2.5 / 0.3 kPa

PCIBS30 No.3 cargo tank IBS pressurePIIBS31 No.3 cargo tank IBS pressure high/low 1.3 / 0.2 kPaDPIBS31 No.3 cargo tank IS/IBS differential pressure h/l 1.2 / 0.0 kPaPIIS35 No.31 cargo tank IS pressure high/low 2.5 / 0.3 kPa

PCIBS40 No.4 cargo tank IBS pressurePIIBS41 No.4 cargo tank IBS pressure high/low 1.3 / 0.2 kPaDPIIBS41 No.4 cargo tank IS/IBS differential pressure h/l 1.2 / 0.0 kPaPIIS45 No.4 cargo tank IS pressure high/low 2.5 / 0.3 kPa

Pressure Control Logic for IBS/IS

Issue: 1 5.2 IBS/IS Nitrogen Pressurisation and Control System Page 2 of 2

Space Pressure Range N2 Supply N2 SupplyValve Full Open Valve Full Open

IBS 0.5 ~ 1.25kPa 0.6 kPa g. 0.8kPa g.IS 1.1 ~ 2.25kPa IBS +0.2kPa g. IBS + 0.4 kPa g.

IBSPress.(kPa g.)

IBS N2Supply ControlValve (CNn16)

IBS N2Exhaust ControlValve (CNn09)

IBS N2Supply ManualValve (CNn18)

IBS N2Exhaust ManualValve (CNn05)

AtmosphericPressure

5.2b IBS Pressure Control

Open

1.15

0.80.9

0.6

0.80.60.40.2

Open

Close

Close

Close

Close

Open

Open

Open

Diff. Press.IBS / IS(kPa)

IS N2Supply ControlValve (CNn25)

IS N2Exhaust ControlValve (CNn10)

IS N2Supply ManualValve (CNn27)

IS N2Exhaust ManualValve (CNn06)

AtmosphericPressure

5.2c IS Pressure Control

Open

Open

Close

Close

Close

Open

Open

Open

IBS Pressure Constant


Issue: 1 5.3 Cofferdam Heating System Page 1 of 6

PI

TIPT

GH609GH610 GH607

No.2 Glycol WaterCirculating Pump

30m3/h

GH606

GH586GH587

TIGW101

LLGW01

TIGW201

PLGW101

PLGW201

DIGW101

DIGW101

TIGW102

THHGW101

TIGW202

THHGW201

TCGW103

TIGW301

TCGW203

PCGW101

PCGW202

PIGW102

PIGW202

PIGW101

PIGW201

GH584

No.1 Glycol WaterCirculating Pump

30m3/h

GH583

GH604

GH605

GH582

GH581

GH602

GH579

GH577

ST557ST552ST558

ST555ST551ST556

GH600

GH590

GH576

GH599

GH589

GH588

GH575

GH598

GH593

GH580

GH503

GH592

GH594

GH595

GH596

GH597

GH611

GH615

AR587

PneumaticTopping UpPump 2m3/h

GH612

Flame ScreenFlame Screen

GH613

GH614

GH616

GH623

GH620GH621

GH622

GH623

GH624

TAHIAS

PIIAS

PHALIAS

TIIAS

TIIAS

TICIASTIAH

IAS

TITIPI

TI TE TI

LS

TEPI

TI TE

TIIAS

TICIAS

TI TE

PI TE

TAHHIAS

TS

GH624

F.W.Filling

ST559

TAHIAS

TIIAS

TIPI TE

TAHHIAS

TS

PT

DPIIAS

DPALIAS

PT

PIIAS

TIIAS

TALIAS

LALIAS

TIPT

PIIAS

PHALIAS

TIPI

PTDPIIAS

DPALIAS

PT

PIIAS

PALIAS

PS

PIPITE

TIIAS

TALIAS

PALIAS

PS

Electric GlycolWater Heater

Glycol WaterExpansionTank 1m3

Glycol Reservoir 6m3

Electric Motor Room

Illustration 5.3.1a Glycol Water Heater

2nd Floor

1st Floor

Mixing Tank0.2m3

Drain Tank0.2m3

ST562ST554ST563

ST560ST553ST561

ST554

From ServiceAir

To HeatingCoils A

To HeatingCoils B

From HeatingCoils A

From HeatingCoils B

Key

Glycol Water

Steam Heating

Air

Domestic F.W.

No.2 GlycolWater Heater

No.1 GlycolWater Heater


5.3 Cofferdam Heating System

5.3.1 Glycol Water Heater(see illustration 5.3.1a)

Electric Glycol Wwater HeaterMake: CetalType: TB 80 20ECapacity: 80kWNo. of sets: 1

Steam Glycol HeaterMake: ASETType: BEU 273-1800 horizontal shell and ‘U’tubeFluid type: Glycol water 45%Rated capacity: 18,000kg/hHeating capacity (steam): 425kg/hNo. of sets: 2

Glycol Water PumpMake: ShinkoType: SVP65M single stage centrifugalCapacity: 30m3/h at 30m headMotor rating: 5.5kWPump speed: 3,495 rpmNo. of sets: 2

The glycol water heating system is located in the cargo motor room and servesthe purpose of heating glycol water which is pumped around the cofferdamsystem to maintain the temperature inside those spaces at approximately +5°C.

The system is comprised of:

Two glycol water centrifugal circulating pumps rated at 30m3/h

Two steam heaters rated at total calorific power 228.2kcal/h with high and low steam demand regulating valves

One standby electric glycol water heater

A glycol expansion tank of 1m3

A glycol storage tank of 6m3 capacity

A glycol mixing tank of 0.2m3

One pneumatic operated expansion tank topping up pump

The glycol heaters are heated from the deck 8kg/cm2 steam range, with thecondensate drains passing back to the engine room via the contaminated steamdrains system.

Each heater is fitted with a high and low steam demand regulator valve.

Glycol Water Supply/Bypass Control Valve Logic


Temp. Range Glycol Water Supply Glycol Water Bypass Low Temp.Side Full Open Full Open Alarm

2 ~ 55°C 2°C 5°C 0°C

Instrument Description Alarm List for Cofferdam Heating Plant Set Point CodeNumber

No.1 Steam Glycol Water HeaterTIGW101 No.1 Glycol Water Return Temperature Low +20ºC TIALPLGW101 No.1 Glycol Water Pump Delivery Pressure Low 1 bar PALDIGW101 No.1 Stm. GW Heater GW/Stm. Diff Press. Low 0.2 bar DPIALPCGW101 No.1 Steam GW Heater Steam Press. High/Low 10/6 bar PIAHLTIGW102 No.1 Steam GW Heater Outlet Temperature High +90ºC TIAHTHHGW101 No.1 Steam GW Heater Outlet Temperature High/High +105ºC THHLLGW01 Glycol Water Expansion Tank Level Low N/A LAL

No.2 Steam Glycol Water HeaterTIGW201 No.2 Glycol Water Return Temperature Low +20ºC TIALPLGW201 No.2 Glycol Water Pump Delivery Pressure Low 1 bar PALDIGW201 No.2 Steam GW Heater G.W/Stm. Diff Press. Low 0.2 bar DPIALPCGW201 No.2 Steam GW Heater Steam Press. High/Low 10/6 bar PIAHLTIGW202 No.2 Steam GW Heater Outlet Temperature High +90ºC TIAHTHHGW201 No.2 Steam GW Heater Outlet Temperature High/High +105ºC THH

Electric Glycol Water HeaterTIGW301 No.2 Glycol Water Return Temperature High +50ºC



No.1 Cofferdam No.2 Cofferdam

No.3 Cofferdam No.4 Cofferdam No. 5 Cofferdam Key

Glycol Water

Illustration 5.3.2a Cofferdam Heating System

GH563

GH569

HeaterA

HeaterB

HeaterB

HeaterA

GH573

GH574

GH572

GH566GH564

GH565GH551

GH558

GH537

GH544

GH523

GH530

GH511

GH517

GH571

GH570GH557

GH568

GH567

GH559

GH552

GH549

GH556 GH560

GH553

GH550

GH561GH562

GH555 GH554

GH543

GH545

GH538

GH535

GH542 GH546

GH539

GH536

GH547GH548

GH541 GH540

GH529

GH531

GH524

GH521

GH528 GH532

GH525

GH522

GH533GH534

GH527 GH526

GH516

GH518

GH512

GH509

GH515 GH519

GH501

From Cargo Motor RoomGlycol Heaters

To Cargo Motor RoomGlycol Heaters

GH507

GH513

GH510

GH520GH619

GH618 GH514

GH502GH504


5.3.2 Cofferdam Heating System(see illustration 5.3.2a)

The purpose of this system is to ensure that the cofferdam is kept at all timesat 5°C, when the cargo tanks are in a cold condition. Each cofferdam is heatedby two independent systems, one is in service, while the other is on standby.

The maximum heating condition is determined by the following extremeoperating conditions:-

External air temperature: -18°CSea water temperature: 0°C

The requirements for the individual cofferdams are as follows:

No.1 cofferdam 41 kcal/h with a heating coil length of 283m

No.2 cofferdam 53.2 kcal/h with a heating coil length of 369m




Any failure of the cofferdam heating system with cargo on board must betreated as serious and repairs must be effected immediately. In the case ofsuspected leaks, regular soundings of the cofferdams will indicate into whichspace glycol water is leaking. Each cofferdam is fitted with three temperaturesensors on each forward and aft bulkhead which will also give an earlyindication of a heating tube failure. Cofferdams No.1 and No.5 have anadditional two temperature sensors.

Any accumulation of water in the cofferdam areas can be pumped out using thepneumatic operated water drain pumps, which are located in No.1 and No.5cofferdam spaces.

Control of the Heating Coils

A temperature element on the outlet side of each cofferdam heater and downstream of the three-way flow control valve, measures the actual value of theglycol water and relays the signal to the IAS. This signal is then processed anda correction value is sent to the heater glycol bypass control valve to maintainthe required temperature.

System OperationGlycol water is circulated through the system of heaters (electric or steam asrequired) by means of a circulating pump (one in use and the other on standby).

Expansion within the system is allowed for by an 1m3 expansion tank to whichtopping up or filling can also be achieved.

The required glycol water make-up is made by a pneumatic pump takingsuction from a 0.2m3 mixing tank. Reserve glycol from a header tank is rundown and mixed with fresh water prior to being fed into the expansion tank.The glycol to water ratio is 45%.

The cofferdam spaces each have two sets of heating coils. The flow of glycoledwater to each set of heating coils is through a three-way valve and a throttlingvalve. The second standby set can be put into service immediately. It isconnected to the running system by a crossover at the pump suction and at theheater outlets.

The automatic temperature control to each circuit is controlled by three-wayvalves GH557 and GH600 adjusting the temperature as required.

The temperature of the electric heater is controlled by the number of resistorswhich are put in service.

The automatic flow control to each cofferdam and liquid dome is achieved bymeans of a three-way valve on each header. The operating signals forregulation is via IAS mimic C-29. Throttling valves on each header return lineare set after conducting trials and should not be adjusted unless in aproblematic situation.


No.1 glycol circulating pump operates on heating coil ‘A’, while No.2circulating pump operates on heating coil ‘B’.

a) Open the circulating pumps’ isolating valves, suction valvesGH586 and GH609, discharge valves GH583 and GH606.

b) Open suction isolating valve GH587 from heating coil ‘A’ to No.1pump and suction isolating valve GH610 from heating coil ‘B’ toNo.1 pump.

c) Open outlet isolating valves to heating coils ‘A’ and ‘B’ GH575,598.

d) Open inlet and outlet from heater No.1, GH581, GH576, and No.2heater GH604, GH599.

e) Open the inlet/outlet isolating valves on the electric heater,GH592, 590. Open crossover isolating valves GH594, 588feeding heating coil ‘A’ and GH595, 589 feeding heating coil ‘B’.

f) Ensure the drop valve from expansion tank, GH612 is open.

g) Open the normal glycoled water supply and return valves to eachset of cofferdam heating coils, i.e. heating coil ‘A’ GH509, 513,521, 525, 535, 539, 549, 553, 563, 567, and heating coil ‘B’GH515, 519, 528, 532, 542, 546, 556, 560, 569, 573.

h) Start circulating pump No.1, either locally or on the IAS mimicC-29.

i) Bleed the system and remove any air from the heating coils.

j) Open the condensate drains form both heaters. Open the steamisolating valves either side of the high and low demand controlvalves.

In the CACC via the IAS.

k) Select glycoled water system mimic C-29.

l) Select No.1 glycol heater as main and No.2 heater as standby. Theelectric heater can also be set in remote or automatic mode.




Illustration 5.3.3a Hull Ventilation

From Dry Air/I.G. System

Passage Way

Passage Way

Trunk DeckTo Cargo

Vapour Line

Injured PersonsManhole ForCofferdam

Pipe DuctNatural Supply

Vent

Passage WayNatural Supply

Vent


Vent


Vent


Vent

Passage WayExhaust Fan

Passage WayExhaust Fan

Pipe DuctExhaust Fan





5.3.3 Hull Ventilation

The cofferdams and pipe duct are inspected on a regular basis in order to checkfor cold spots, condition of the paint work and general inspection of piping,fittings and valves. In general it should be expected to inspect one cofferdamarea per month.

Before entering the cofferdam/pipe duct spaces, the compartments must firstbe ventilated. The ship is fitted with a mechanical exhaust fan which is situatedforward above No.1 cofferdam. Above No.5 cofferdam is a natural supplymushroom vent which must be opened before starting the exhaust fan.

When it is judged that the atmosphere inside the cofferdams is safe, entry canbe made. The entry personnel must take with them a personnel O2 meter. Theportable detector head should be lowered down to each level as they proceed.

(Note ! If it has been found the the nitrogen consumption has increased beyondnormal acceptable levels, then added precautions should be observed beforeentering the cofferdam spaces.)

Each cofferdam is fitted with a manhole cover located on the starboard side,which maybe removed and a portable gas freeing fan fitted to which is attacheda flexible ducting. This is also the location that any injured person can beremoved from the cofferdam space.

On the port side of each cofferdam is a fixed pipework installation which leadsto the base of the tank, onto which a portable gas freeing fan can also be fitted.A stub piece on the side of the pipe is flanged and blanked, its purpose is tobe able to connect up to the dry air/IG supply via a 300mm flexible pipe.

There are two portable supply fans for the cofferdam spaces on board the shipwhich give a total air volume flow of 24,000m3/h.

The passageway areas, port and starboard, are equipped with a mechanicalexhaust fan located midships and two mushroom natural supply vents forwardand aft. The passageway areas have the facility to be connected to the dryair/IG emergency vent line via four blanked off stub pieces welded to the deck,two port and two starboard and a 300mm flexible hose.

The trunk deck areas have four manhole covers, two forward and two aft. Theaft manholes are used to fit a portable supply fan for gas freeing, with theforward manholes being removed for exhausting during gas freeing.



Issue: 1 5.4 Ballast Tank Blowing System Page 1 of 2

Illustration 5.4a Ballast Tank Blowing System

No.4 W.B.T. Starboard

No.4 W.B.T. Port


No.3 W.B.T. Port


Trunk Deck

Water BallastTank

Air Vent PipeVent Head

Air Vent PipeVent Head

Musasino Ballast Tank Gauging

No.2 W.B.T. Port


No.1 W.B.T. Port

AR604

AR603

AR601 Bosun'sStore

AR602

AR601

AR620

AR600

AR606

AR605

AR608

AR607

AR610

AR609

Fore PeakTank

Blow OffSilencer

SuctionFilter/

Silencer

Compressor

DischargeFilter A

Passage Way

Key

Air Vent Pipe

Ballast Tank Blowing Compressor

Compressed Air

CompressedAir Main

Air BlowingConnection


5.4 Ballast Tank Blowing System

Ventilating a Double Hull Ballast Tank(see illustration 5.4a)

Ventilation of ballast tanks is necessary to ensure that the atmosphere inside thetank is safe before entry can take place. The oxygen content in the tank may below, for example, due to the effects of corrosion.

The SK Shipping regulations for tank entry must be complied with. A permitto work must be completed prior to entry and adhered to.

The double hull ballast tanks can be ventilated via the forced ventilationsystem. The forced ventilation system consists of an oil free screw compressorwhich is housed in the bosun’s store forward. Delivery from the compressor isvia a 125mm fixed pipeline, with branches leading off to the double hull ballasttanks and the fore peak tank. The lines are terminated close to the air vent pipehead of the respective ballast tank and are fitted with butterfly isolating valves,with blanks on the outlet from the valve. In order that a tank maybe ventilated,the air vent pipe vent head must first be removed and a flexible 125mm hosefitted.

The ballast tank to be inspected must first be deballasted via the main andstripping line. Warning notices must then be posted in the CACC and ESCRthat the ballast pumps are isolated and should not be started.

Pump SpecificationManufacturer: HibonType: Oil free compressor Model: HCS 26Air flow: 1,222 m3/hInlet pressure: 1bar abs.Inlet temperature: 40°CDifferential pressure: 1bar g.Discharge pressure: 2 bar abs.Discharge temperature: 132°CCompressor speed: 9,653 rpmMotor speed: 3,570 rpmMotor power rating: 55kWNo. of sets: 1

The control cabinet for starting and stopping the compressor is located in thebosun’s store.

! WarningThe spaces to be inspected must be thoroughly ventilated before entry asthere is the possibility of very low oxygen content due to corrosion of thesteelwork.

Forced Pressurisation of a Ballast Tank

In the event of a grounding or collision it is possible to limit the ingress of seawater into a ballast tank by pressurising the compartment from the aircompressor situated in the bosun’s store.

Caution !Pressurisation of a ballast tank shall be limited to within the maximumallowable stresses imposed on the hull construction and ship’s scantlings.

The ship is arranged with a supply pipeline running down the starboard side ofthe ship from the high volume low pressure compressor situated in the bosun’sstore with branches off (see illustration 5.4a). In the event of a ballast tankrequiring to be pressurised, it is first necessary to remove one set of vent pipevent heads and attach a flexible 15m hose (four hoses are kept in the bosun’sstore for this purpose). The other corresponding ballast tank vent pipe venthead is removed and fitted with a blanking plate, to which is fitted amonitoring pressure gauge.

In the event of the compressor being out of working order, or the supplydemand is to great, it is possible to connect to the general service supply. Thisis achieved by reversing the spectacle blank situated in the bosun’s store andusing the isolation and throttling valve to regulate the supply of compressed airfrom the general service air system.

Issue: 1 5.4 Ballast Tank Blowing System Page 2 of 2

Instrument Description Alarm List for Ballast Tank Blower Set Point CodeNumberPDSH020 Filling indicator 50mbTSH021 Discharge compressor temperature high 200ºC ShutdownTSH017 Oil temperature high 90ºC ShutdownPSL023 Low oil pressure 0.2 bar g. Shutdown


Issue: 1 5.5 Fire Fighting System Page 1 of 12

PI PI(Locked Open)

FD619

FD606

SeaChest

Steering Gear Room

(Locked Open)

(Locked Closed)

FD575

FD578

FD016

FD012

FD033

FD032

FD037

FD011

FD036

FD020

FD013FD001

FD003

FD005

FD010

FD554FD602

FD002

FD006

FD015

FD014

AC120

FD004

AutoST/SP

From Control AirService Line

To Accommodation

To Accommodation

Fire Jockey Pump2m3/h

From MainCrossover Line

Emergency FirePump 110m3/h

From EngineRoom BilgeMain Line

From MainCrossover Line

Direct BilgeSuction

From Clean Drain Tank

HydrophoreTank2m3

To Hawse pipe

To Bilge EductorFor Bosun Store

To Bilge EductorFor Forward Pump Room

To Bilge EductorFor Bow Thrust Room

To Hawse pipe

FD511 FD509

FD510

FD519

FD598

FD599

FD517

FD516

FD518

FD611

FD612

FD521

FD527

FD525

FD524

FD538

FD532

FD533

FD539

FD528

FD529

FD614

FD526

FD520

FD613

On TrunkDeck

On TrunkDeck

Illustration 5.5.1a Fire and Wash Deck System

FD574

FD571

FD593

FD540

FD541

FD547

FD546

FD542

FD543

FD600

PI PI

PI PI

PS

PI PI

FD595

FD615

FD616

FD558

FD560

FD556

FD557

FD559

FD601

FD594

FD561FD569

FD570

FD604

FD617

FD566

FD567

FD564

FD565

FD549

FD548

FD555FD603

FD596

PI

No 1

No 2

Bilge, Fire and GeneralService Pump245/150m3/h

To Bilge Eductor

To Bilge Eductor

To SwimmingPool

To Bilge Eductor

FD535

CargoManifold

CargoManifold

FD537 FD536

FD534

From Water Spray Pump

To BallastEductor

Key

Sea Water

Compressed Air

Electrical Signal


5.5 Fire Fighting System

5.5.1 Fire and Wash Deck System

The fire main system is supplied from the engine room, by the two bilge, fireand GS pumps. They are two speed centrifugal pumps, with a delivery capacityof 150m3/h at 12 kg/cm2.

The emergency fire pump is mounted in the steering gear compartment in awell. The emergency fire pump is a self-priming centrifugal pump with its owndirect sea suction. The pump is rated at 110m3/h at 12kg/cm2 and is suppliedfrom the emergency switchboard.

In order to prevent bilge water being directed onto the fire main, interlockvalves are fitted. When the fire, bilge and GS pump fire main dischargeisolators are opened, a pressure signal is sent to the pump bilge suctionisolators. This signal acts upon an actuator and thereby ensures that the bilgevalve closes and cannot be opened until the fire main isolator is closed.

The fire main is kept pressurised by a 2m3 hydrophore tank and a topping uppump rated at 2m3/h at 12kg/cm2. The topping up pump has an automaticpressure cut in/out switch. The fire main is kept topped up and under pressureat all times.

The deck fire main has a main isolator valve, FD561, before the port andstarboard main ring main isolator valves. The ring main is fitted with a furtherfour section isolator valves on each side at regular intervals along up the deck,before the forward deck ring main crossover isolating valve FD510. This is toallow any part of the system to be supplied from either side of the ship.

The fire main also serves the water curtain below the port and starboardmanifold areas during loading and unloading conditions.

The fire main supplies the driving water for the bilge eductors in the pipetrunk-way, duct keel pipe duct, forward pump room, bow thrust room andbosun’s store. The fire main also supplies anchor washing water and theswimming pool filling.

There are 24 fire hydrants situated along the cargo deck, each with its fire hosemounted adjacent.

The emergency fire pump can be started locally, from the bridge via IAS mimicC-9, CACC via IAS mimic C-9 or the fire control station on U deck.

Under normal operating conditions, the fire main will be under pressure duringport time, supplying the manifold water curtain and with hoses run out as a fireprecaution.



Emergency Fire Pump in Steering Gear Compartment

Fire System Hydrophore Tankand Jockey Pump


PI PI

SP573

SP571

SP572

SP574

SP566SP567SP568SP569

SP562SP563SP564SP565

SP561

SP545

SP544

SP543

SP542

SP541

SP552 SP554

SP555SP553

No.4 CargoTank

No.3 CargoTank

No.2 CargoTank

No.1 CargoTank

SP546

FD019

Spray Water

FD033 SP575 SP576

FD032

LockedClosed

Illustration 5.5.2a Water Spray System

Key

To / FromFire Main

No.1 GroupValve

To BallastStripping Eductor

Spray Pump700m3/h

Engine Room

FD042

SP533

SP531SP506

SP502

SP501

SP505

SP523

SP522 SP521 SP511SP513SP532

No.4 GroupValve

No.3 GroupValve

No.2 GroupValve


5.5.2 Water Spray System

The accommodation block front, compressor house, cargo tank liquid andvapour domes and manifold areas are protected by water spray from the effectsof fire, gas leakage or liquid spill. There is a 700m3/h spray pump, mounted onthe engine room floor level, delivering to four spray rails across the accom-modation block front, lifeboat embarkation areas port and starboard,compressor house sides and deck domes/manifolds. They are grouped into foursections as follows:

Group 1 Accommodation and lifeboat embarkation area

Group 2 Cargo machinery and electric motor room

Group 3 Cargo liquid dome, cargo vapour dome

Group 4 Cargo manifold

Each group main spray rail has a remotely operated hydraulic isolating valveoperated from the fire control room. The spray pump can be started locally andfrom the wheelhouse via IAS mimic C-9, CACC via IAS mimic C-9, on themain deck close to the accommodation exits and fire control station on U deck.

Each main group is sub-divided into smaller sections, with a flow regulatingand section isolating valve fitted. The accommodation front is covered by fivesuch sub sections, beginning at deck level C, right through to thenavigation/bridge deck. The decks below C deck will have sufficient flowpassing over them that they do not need to be covered by a fixed rail.

The nozzle arrangement is as shown below. For plain vertical surfaces, nozzlesare set 800mm apart and at 45° to the vertical. Headers are 250mm frombulkheads and nozzles are flat cone design.

Number of Nozzles and Capacity

Group 1

C-deck 20 nozzles at total flow 378 l/m

D-deck 20 nozzles at total flow 378 l/m

E-deck 20 nozzles at total flow 378 l/m

F-deck 20 nozzles at total flow 378 l/m

Nav/bridge-deck 16 nozzles at total flow 312 l/m

Lifeboat embarkation

Port 10 nozzles at total flow 55 l/m

Starboard 10 nozzles at total flow 55 l/m

Group 2Cargo machinery/electric motor room

Front 22 nozzles at total flow 415 l/m

Aft 22 nozzles at total flow 415 l/m

Port 34 nozzles at total flow 624 l/m

Bottom 39 nozzles at total flow 1,287 l/m

Master cargo valve 1 nozzle at total flow 14.5 l/m

Group 3

No.1 liquid dome 12 nozzles at total flow 592 l/m




No.1 vapour dome 3 nozzles at total flow 98.5 l/m

No.2 vapour dome 4 nozzles at total flow 113 l/m



Group 4Cargo manifold

Port 7 nozzles at total flow 1,199.3 l/m

Starboard 8 nozzles at total flow 1,211.0 l/m

There are drain connections provided at main deck level below the manifoldarea and below the cargo machinery room.

The water spray pump is used to supply the ballast main eductor systemthrough a screw lift non-return valve FD032 in the engine room. The waterspray pump can also be cross connected onto the fire main in an emergency viavalve FD033 located in the engine room. Under normal circumstances thisvalve is kept locked shut.




To Hand Hose (1)

To Hand Hose (2)

To Hand Hose (4)

To Hand Hose (6)

To Hand Hose (8)

To Hand Hose (3)

To Hand Hose (5)

To Hand Hose (7)

Dry Powder Tank Unit No.3 - Aft

Local

Port

Stb'd

Local

Dry Powder Tank Unit No.1 - Port

Fire Control Station

C.A.C.C

Dry Powder Tank Unit No.4 - ForwardDry Powder Tank Unit No.2 - Starboard

No1 Tank No3 Tank

No4 TankNo2 Tank

Nitrogen Expulsion Cylinders Nitrogen Expulsion Cylinders

Nitrogen Expulsion CylindersNitrogen Expulsion Cylinders

Illustration 5.5.3a Dry Powder System

ExhaustLine

Cleaning Line

Cleaning Line

Cleaning Line

ExhaustLine

Cleaning Line

ExhaustLine

Cleaning Line

Cleaning Line

ExhaustLine

Cleaning Line

Cleaning Line


5.5.3 Dry Powder System

General Description

The dry powder firefighting system is supplied by NK Fire Protection andconsists of 4 separate units.

Main System

Two dry powder units are situated on the main deck midships, one port and onestarboard. Each unit contains a 1518kg dry powder storage tank, 8 nitrogenexpellent cylinders of 68 litre each and a single dry powder monitor with anoutreach of 250m.

Operation of the system can be carried out from a cabinet in the fire controlroom, CACC and locally. Activation of the nitrogen pilot cylinders in thecabinets allows the high pressure gas to flow into the main valve (before themonitor) actuator, thereby causing the valve to open. The nitrogen is nowported to the release mechanism for the gang nitrogen expulsion cylinders.

The eight high pressure nitrogen cylinders are now released and flow into themain dry powder tank through an upper and lower injection pipe. When the

tank pressure has reach a sufficient pressure, a pressure release valve operates,thereby allowing the residual nitrogen in the expellent pipework to open themain outlet from the tank. Operation of the manual valve at the monitor willnow allow the dry powder to be used as required.

After the system has been used it is necessary to ensure the expellent pipe workand more importantly, that the main valves are blown clear on any remainingdry powder.

Hose System

Two dry powder units are situated on the main deck, one forward and one aft.Each unit contains a 925kg storage tank, 5 nitrogen expellent cylinders of 68litre each and 4 dry powder hose cabinets which are situated along the maindeck centre line from forward to aft. Each hand held hose has an outreach of33m.

Operation of the unit is from either of the four associated hose cabinets.Activation of the nitrogen pilot cylinders in one of the cabinets allows the highpressure gas to flow into the main valve (before the hose) actuator, therebycausing the valve to open. The nitrogen is now ported to the release mechanismfor the gang nitrogen expulsion cylinders.

The five high pressure nitrogen cylinders are now released and flow into themain dry powder tank through an upper and lower injection pipe. When thetank pressure has reach a sufficient pressure, a pressure release valve operates,thereby allowing the residual nitrogen in the expellent pipework to open themain outlet from the tank. Operation of the manual valve at the hose will nowallow the dry powder to be used as required.

After the system has been used it is necessary to ensure the expellent pipe workand more importantly, that the main valves are blown clear on any remainingdry powder.


Illustration 5.5.3b Dry Powder Locations

8 7 6 5 4 3 2 1

No.4

No.1

No.2

No.3 Dry PowderUnit

Dry PowderUnit

Dry PowderUnit

Dry PowderUnit

Hose Cabinets


Dry Powder Remote Operation Unit at Manifold Area

Hand Held Dry Powder Unit


To Safe Area

Key

CO2 Pilot Line

Electrical

P

T D

Main Valve

Check Valve

InstructionChart

Key Box

Time Delay

CO2 Pipe LinePI

To Junction Box(For CO2 Alarm and Vent Stop)

T D T D T DT DT D

13 BottlesCargo Mach.

Room

2 BottlesCargo Motor

Room

5 BottlesEmg'yGen'rRoom

3 BottlesPaintStore

7 BottlesCargoSWBRoom

PI PS

Illustration 5.5.4 CO2 System

PP P P P

CO2 Nozzles

ETo AlarmRelay Box

E

To AlarmRelay Box

E To AlarmRelay Box

L To AlarmRelay Box

Cargo SwitchBoard Room

L

To AlarmRelay Box

L

To AlarmRelay Box

EmergencyGenerator

Room

PaintStore

ElectricMotorRoom

CargoMachinery

Room

Cargo SwitchboardRoom

EmergencyGenerator

Room

PaintStore

Electric MotorRoom

Cargo MachineryRoom

A

A

To AlarmRelay Box

PI

To Junction Box(For CO2 Alarm and Vent Stop)

Cargo SwitchboardRoom

EmergencyGenerator

Room

PaintStore

Electric MotorRoom

Cargo MachineryRoom

Fire Control Station

CO2 Room


5.5.4 CO2 System

Cargo Deck CO2 Flooding System

Maker: NKType: High pressureCapacity: 25 cylinders each containing 45kg

The CO2 flooding system for the cargo areas consists of 25 high pressurecylinders, each of 45kg. These are contained in CO2 room, situated on upperdeck starboard side.

The deck CO2 system covers the following areas:

Cargo machinery room, cylinders required: 13

Electric motors room, cylinders required: 2

Cargo switchboard room, cylinders required: 7

Emergency generator room, cylinders required: 5

Paint store, cylinders required: 3

Flooding of the protected areas is achieved by the operation of the ball valvesfrom their respective cabinet in the fire control station or CO2 room and therelease of the pilot CO2 cylinders. Upon opening the control cabinet door, theCO2 alarm is activated and the ventilation fans for that area are stopped. Thepilot gas is directed by the operation of the respective ball valve, onto the gangrelease line (having first operated the time delay switch down stream of the HPcylinders) and master valve for the selected area.

The emergency generator room and paint store both share the same CO2

cylinders, although they have a separate main discharge line to their space.

! WarningRelease of CO2 into any space must only be considered when all otheroptions have failed and then only on the direct instructions of the Master.

In the Event of Fire in a Protected Room

a) Go to the master control cabinet located in the CO2 room or firecontrol station.

b) Break the key box glass and take the key.

c) Unlock the cabinet and open the door.

d) The rotating lights (cargo machinery room, electric motors roomand paint store) and electric horns (cargo switchboard room andemergency generator room) will operate.

e) The room ventilation fans will stop.

f) Ensure all personnel have evacuated the compartment room andhave been accounted for.

g) Close, and check that all doors, hatches and fire flaps are shut.

h) If the fire is in the emergency generator room, operate the DOtank quick-closing valve from the wire pull situated directly bythe entrance to the room.

i) Open the valve on one pilot cylinder.

j) Operate the ball valves on the line to the protected room.

k) After the time delay of 30 seconds the cylinders will release.

l) If the pilot system fails to operate, the main valve can be openedmanually from the CO2 room and the cylinders released by hand.

m) Do not re-enter the room for at lease 24 hours and ensure allreasonable precautions have been taken, such as maintainingboundary inspections, noting cooling down rates and/or any hotspots which may have been found. After this period, anassessment party donning breathing apparatus can enter the spacequickly through a door which is then shut behind them. Checkthat the fire is extinguished and that all surfaces have cooled priorto ventilating the engine room. Premature opening could cause re-ignition if oxygen contacts hot combustible material.

n) Do not enter the the room without breathing apparatus until thespace has been thoroughly ventilated and the atmosphere provedsafe.

Should any cylinder discharge accidentally, it will pressurise the main line upto the stop valve. This line is monitored by a pressure switch and will activatethe "CO2 leakage" alarm in the ESCR.

Over pressure of the main line is prevented by a safety valve, which will ventthe gas to atmosphere.



To CargoMachinery

Room

To PaintStore

To EmergencyGenerator Room

To CargoElectric Motor

Room

To CargoSwitchboard

Room


1 2 3 4 5 6 7 8

9 10 11 12 13 14 t15 16

17 18 19 20 21 22 23 24

25 26 27 28 29 30 31 32

33 34 35 36 37 38 39 40

41 42 43 44 45 46 47 48

49 50 51 52 53 54 55 56

57 58 59 60 61 62 63 64

65 66 67 68 69 70 71 72

73 74 75 76 77 78 79 80

ZONE DISPLAY

FIRE FAULT DISABLEDMINERV MARINEA FIRE CONTROLLER

15 Nov 12 : : 1

NODELETE

YESENTER

1 2 3

4 5 6

7 8 9 0

QUIT

FASTACCESS

POWERON

POWERFAIL

FIREALARM

LAMPTESTSILENCE RESET

Illustration 5.5.5a Fire Detection System


5.5.5 Fire Detection System

Manufacturer: Thorn SecurityType: Minerva Marine T890

The T890 fire detection system is a complete fire detection and alarm system,including combined fire alarm and operating panels, control units and powersupply units, all contained in single cabinets. The master panel is fitted on thebridge with three remote repeater panels included in the system. These arefitted in the CACC room, ESCR and fire control station. Fire and smokedetectors and manual call points are connected to the system in loop configu-rations.

There are a wide range of fire detectors and sensors fitted to suit differentrequirements and conditions, such as smoke, heat and flames, watertight, non-watertight and explosion proof detectors. Manual call points, short circuitisolators and timers are connected to the loop where required. A fault in thesystem or a false alarm is detected immediately, since the function of thedetectors and other installed loop units are automatically and continuouslytested. The relay outputs of the system can be used to control doors andventilation systems.

Central Unit Panel

The central unit panel is divided into two parts, the fire alarm and zoneindication panel on the left and the operating and information panel on theright. The fire alarm indications and alarm are activated when there is a firealarm on the system. The operator verifies and supervises the system by usingthe different keys and the display on the operating panel.

Controls

The operating panel consists of a text display information window, indicationlamps, operating buttons and numerical keypad. These control items enable theentire fire detection and alarm system to be controlled.

The keyswitch has three positions, NORMAL, TRAPPED NORMAL andENABLE. The keyswitch is used to enable the three fire control keys, FIREALARM, SILENCE and RESET.

The positions of the keyswitch are not indicated for security reasons but are asfollows:

Normal: 10-o'clock position

Trapped normal: 12-o'clock position

Enable: 2-o'clock position

In the TRAPPED NORMAL position, the key is retained, in the NORMALposition, the key may be removed. When the key is in the ENABLED position,the display is backlit and the SILENCE and RESET keys are highlighted.

The FIRE ALARM key is used to activate all the ship’s audible fire alarms.

The SILENCE key is used to silence the audible alarms and the internal buzzer.

The RESET key is used to reset the system after an alarm or an event.

The LAMP TEST key is used to test all the panel indicators and the buzzer.

The YES/ENTER key is used in ‘data entry’ mode to enter a command into thecontroller. It may also be used in ‘query’ mode to provide a ‘Yes/positive’response.

The NO/DELETE key is used in data entry mode to edit text, providing abackspace and delete function. It may also be used in response to a displayedquery to provide a ‘No/negative’ response.

The up and down arrow keys are used to scroll through a display or log oneentry at a time. Holding the arrow keys down will scroll the display text con-tinuously.

The QUIT key is used to terminate and exit from the current command ordisplay.

The FAST ACCESS key is used to access a system option quickly, without theneed to use the menus. After pressing this key, a numeric code is entered, cor-responding to the option required. The codes are available from the manufac-turer’s manual.

The keypad is used for accessing and entering numerical system/optioninformation.

There is an internal buzzer to attract the attention of the operator.

LED Indicators

POWER ON: Indicates the presence of system electrical power

POWER FAIL: Indicates the failure of all system electrical power

FIRE: Indicates the presence of a fire condition

FAULT: Indicates the presence of a system, sensor or loop fault

DISABLED: Indicates the disabling of a circuit/detector (eg, isolation)

FIRE ZONES: Indicate an alarm in the relevant zone

In normal conditions, i.e., no fire alarms or system faults, the display panel willindicate the date and the time.

Fire Alarm

The following indications appear on the control panel in the event of a firealarm:

The red FIRE indication LEDs flash and the alarm sounds

The red ZONE(S) indication LEDs flash

The text display indicates the address(es) of the detector(s)which initiated the first fire alarm

All sounders/fire doors/alarms/fan stops are activated(as connected/programmed)

Action to be Taken in the Event of a Fire Alarm

Follow the company’s requirements for dealing with such an emergency. Whenthe scene of the fire has been investigated and the necessary action carried out,the sounders may be switched off as follows:

a) Move the keyswitch clockwise to the ENABLE position.

b) Press the SILENCE key, the ZONE LED will continuouslyilluminate and the audible alarms will be silenced.

c) The text display will indicate the address of the activated detectoruntil the system is reset.

When the alarm has cleared, i.e. the detector is not in an alarm condition, thesystem can be reset as follows:

d) The operator keys in their individual passcode and presses theYES/ENTER key.

e) The display will indicate the following message:‘Do you want to accept events?

f) The operator presses the YES/ENTER key again and the displaywill show the address of the detector that was in alarm. A blacksquare will flash in the display indicating that an operator input isrequired.

g) The operator presses the YES/ENTER key. The display willindicate that the event has been accepted.

h) The RESET key can now be pressed to reset the system. TheRESET key will only perform a reset function after the SILENCEkey is pressed beforehand. The display indicates that the systemis resetting and after a countdown will indicate that the reset iscomplete.




1 2 3 4 5 6 7 8

9 10 11 12 13 14 t15 16

17 18 19 20 21 22 23 24

25 26 27 28 29 30 31 32

33 34 35 36 37 38 39 40

41 42 43 44 45 46 47 48

49 50 51 52 53 54 55 56

57 58 59 60 61 62 63 64

65 66 67 68 69 70 71 72

73 74 75 76 77 78 79 80

ZONE DISPLAY

FIRE FAULT DISABLEDMINERV MARINEA FIRE CONTROLLER

15 Nov 12 : : 1

NODELETE

YESENTER

1 2 3

4 5 6

7 8 9 0

QUIT

FASTACCESS

POWERON

POWERFAIL

FIREALARM

LAMPTESTSILENCE RESET

Illustration 5.5.5a Fire Detection System


i) As long as there are no further events or faults present on thesystem, the display will revert to the date/time display.

Prewarning

In certain conditions, such as a rise in the detector ionisation level, a detectormay trigger a prewarning alarm. This may be a prelude to an actual fire alarmas smoke may be building up but the level has not reached the alarm threshold,so the alarm should be thoroughly investigated.

The following indications appear on the display in the event of a prewarning:

The text display indicates the address(es) of the detector(s)which are in the in prewarning mode

The internal buzzer sounds

The event is logged and must be accepted

If the detector which activated the prewarning event subsequently goes intoalarm, a full alarm is raised regardless of whether or not the prewarning eventhas been accepted.

Faults

The following indications appear on the control panel in the event of a fault.

The yellow FAULT indication LED flashes

The internal buzzer sounds continuously

The text display indicates the nature and address of the fault

Action to be Taken in the Event of a Fault

a) Move the key switch clockwise to the ENABLE position.

b) Press the SILENCE key, the audible alarms will be silenced.

c) The text display will indicate the address and/or nature of the faultuntil investigated and cleared.

When the fault has cleared, the system can be reset as follows:

d) The operator keys in their individual passcode and presses theYES/ENTER key.

e) The display will indicate the following message:‘Do you want to accept events?

f) The operator presses the YES/ENTER key again and the displaywill show the fault message. A black square will flash in thedisplay indicating that an operator input is required.

g) The operator presses the YES/ENTER key. The display willindicate that the event has been accepted.

h) The QUIT key can now be pressed to exit the system.

i) As long as there are no further events or faults present on thesystem, the display will revert to the date/time display.

Detector and Zone Isolation

Detectors and groups of detectors may be isolated so that they do not respondto any alarms.

(Note! The isolation procedure should not be used when detectors are to beremoved. In this instance the system should be powered down. See the manu-facturer’s manual for further in-depth information.)

To Isolate a Zone

a) Select the ISOLATE option from the main menu.

b) The operator is asked if the isolation of points is required. Bypressing the YES key, the operator is given the choice of isolatingzones or points.

c) Select the option required and press the YES key.

Zones

This option isolates all the detectors in a selected zone.

a) The ‘Isolate Zone’ option is selected as above. The display willindicate that the zone number should now be entered If 0 isentered, none will be selected, if YES is entered, all zones will beisolated.

b) Enter the required zone number to be isolated and press theYES/ENTER key.

c) The display will indicate the text ISOLATE SUCCESSFUL,when the isolation has been carried out.

d) The DISABLED LED will illuminate and the internal buzzer willsound approximately every 30 seconds until the system is readyfor another isolation. This will be indicated by the display of thetext ‘Isolate zone (sensor only)’, allowing a further zone to beisolated if required.

Points

This option isolates individual detectors in a selected loop (addressable loopsonly).

a) The ‘Isolate Point’ option is selected as above. The display willindicate: ‘Loop: A Y/N?’. If the detector to be isolated is on loopA, press the YES/ENTER key. If the detector is on another looppress the NO/DELETE key and proceed to step (e).

b) The display will indicate: ‘Point no.:’ (if 0 is entered, none will beselected, if YES is entered, all zones will be isolated) Enter theaddress of the detector and press the YES/ENTER key.

c) The display will indicate the text ‘isolate successful’, when theisolation has been carried out.

d) The DISABLED LED will illuminate and the internal buzzer willsound approximately every 30 seconds until the system is readyfor another isolation. This will be indicated by the display of thetext ‘Isolate point’, allowing a further point to be isolated ifrequired.

If the detector is on another loop:

e) After pressing the NO/DELETE key, the display will indicate:‘Loop: B Y/N?’. If the detector to be isolated is on loop B, pressthe YES/ENTER key. If the detector is on another loop press theNO/DELETE key.

f) When the required loop is reached and selected, the display willindicate: ‘Point no.:’ (if 0 is entered, none will be selected, if YESis entered, all zones will be isolated). Enter the address of thedetector and press the YES/ENTER key.

g) The display will indicate the text ‘isolate successful’, when theisolation has been carried out.

h) The DISABLED LED will illuminate and the internal buzzer willsound approximately every 30 seconds until the system is readyfor another isolation. This will be indicated by the display of thetext ‘Isolate point’, allowing a further point to be isolated ifrequired.

The procedure to reinstate detectors and zones is almost identical to the aboveprocedures. The operator should select the ‘De-isolate Zones’ option from the main menu and follow the instructions and prompts as above. When complete,the display will indicate ‘De-isolate successful’, the zones or detectors are nowback on-line.



Issue: 1 5.6 Auxiliary FW Cooling System Page 1 of 2

PI TI PI TI

PI PI

PI PI

PI TI PI TIPI

TI

TTTT

PT

PS

TI PI TI

PI TI PI TI

TI

PITI

TI

TI

TI

TI

Illustration 5.6a Auxiliary Fresh Water Cooling System

Key

LT Cooling Water

Sea Water

Control Air

No.1 HD CompressorLO Cooler

Control Air

No.2 HD CompressorLO Cooler

No.1 LD CompressorLO Cooler

From Main EngineSea Water Cooling System

No.2 LD CompressorLO Cooler

No.2 Aux. Fresh Water Pump

De-aerationChamber

Auxiliary Fresh Water

Expansion Tank(1 m3)

To BilgeWell

AutoCH-VR

I / PPI

PIW92TC

TCW92TI

TIW92

No.1 Aux. Fresh Water Pump

WS502WS509

WS512

WF534

WF534

WF534

WF527

WF528

WF529

WF530

WF525

WF501

WF503 WF504

WF502

WF520

WF517

WF515

WF513

WF512

WF511

WF514

WF516

WF518

WF519

WF524WF522 WF523WF521

WS502

WS504

WS504

WS505 WS508

WS506

No 1 FW Cooler No 2 FW Cooler

WS507

Drain Cooler

Hydraulic Oil CoolerFor Deck Machinery

Hydraulic Oil CoolerFor Deck Machinery


5.6 Auxiliary Fresh Water Cooling System

General Description

The independent deck cooling fresh water system is provided by two cargoauxiliary fresh water pumps. The pumps, FW coolers and header tank aresituated in the cargo electric motor room.

One pump is normally in service, while the second pump is on automaticstandby cut-in mode.

The FW coolers are in turn directly cooled by a sea water line from the engineroom auxiliary CSW system.

The FW cooling system is used to serve the following equipment;

HD compressor LO coolers

LD compressor LO coolers

Cargo machinery room steam drains cooler

Forward deck machinery hydraulic oil coolers

Temperature control is achieved by means of a three way control valve,situated on the outlet side of the auxiliary FW cooler, with a set point of 35°C.

The system is provided with a 1m3 header tank which has a domestic freshwater topping up connection via a tundish on the top of the tank. The chemicalcondition of the cooling water should be regularly checked, with any dosingrequired being directly added into the header tank.

(Note ! There is no facility for direct injection of chemicals into the system.)

The sea water cooling outlet from the auxiliary FW coolers is extended by 1mabove the cooler in an anti-syphon loop, before passing overboard throughNo.4 starboard ballast tank.

SpecificationManufacturer: ShinkoType: SVS125MNo. of sets: 2Rated output: 110m3/h at 3kg/cm2

FW cooler bypass control: 35°C


One auxiliary FW cooling pump and one FW cooler are normally required tomeet the system cooling demand.

a) Ensure all the drains and vents are shut and that the header tankoutlet valve to the deaerator is open. Check the level in the headertank.

b) Open the FW cooler inlet and outlet valves of the cooler to beplaced in use.

c) Open the inlet and outlet valves on both auxiliary FW coolingpumps.

d) Open the valves on the respective system to be cooled i.e. HDcompressor LO cooler, LD compressor LO cooler, steam drainscooler and forward hydraulic oil cooler. Check for leaks.

e) Open the sea water overboard discharge valve WS509.

f) Open the sea water inlet and outlet valves on the auxiliary FWcooler.

g) Select one of the pumps on local control and start the pump.Check that the system pressures are normal.

h) Select the other pump on standby via cargo mimic C-37.

i) Stop the running pump and ensure that the standby pump cuts in.

j) Return the pumps to their original running condition i.e., onepump running and the other on standby auto cut-in.

Control and Alarm Settings

Tag No. DescriptionTIW92 ref 2104 Auxiliary CFW cooler outlet temperature high

Set point: 40°C

LLW92 ref 2114 Auxiliary CFW expansion level lowSet point: Float switch

PIW92 ref 2126 Auxiliary CFW pump pressure lowSet point: 1 kg/cm2

PLS92 ref 2128 Auxiliary CSW system pressure lowSet point: 2.5 kg/cm2

Issue: 1 5.6 Auxiliary FW Cooling System Page 2 of 2


Deck Auxiliary Fresh Water Circ Pumps and Coolers in the Cargo Electric Motor Room

Issue: 1 5.7 Deck Scupper and Bilge System Page 1 of 2

BC501

BC502BC503

BC505

BC504

Key

Compressed Air

Bilge Line

Illustration 5.7a Deck Scupper and Bilge System

BC509

To Engine RoomBilge Primary

Tank

BC507

BC508

Bilge WellsPort and

Starboard

Bilge WellsPort and

Starboard

Bilge WellsPort and

Starboard

PneumaticBilge Pump

5m3/h

Air Regulating Valve

AR586

Electric MotorRoom

Cargo Machinery Room

LAHLHB15A

LAHLHB15B

LAHLHB13A

LAHLHB13B

LAHLHB11A

LAHLHB11B

Cargo Machinery RoomElectric MotorRoom


5.7 Deck Scupper and Bilge System

The ship is fitted with a number of scuppers around the deck accommodationareas as well as the forward and aft mooring areas. These lead directly oversidevia scupper pipes and are normally free running, but if it is required to securethe deck to protect against the discharge overside of pollutants, there arescupper plugs which can be fitted.

The main cargo deck gutterways in way of the gunwale are fitted with fourscuppers and plugs each side, port and starboard, with the run off being directlydown the ship’s side and not via piping. During cargo and bunkeringoperations, the plugs are fitted.

The cargo machinery and electric motor rooms are fitted with bilge hats, portand starboard, with high-level alarm indication in each well. The bilge wells inthe cargo machinery room are discharged via a 5m3/h pneumatic pump locatedbelow the demister in the cargo machinery room. The driving air is suppliedvia the deck general service air system with a speed regulating control valve.The individual manual bilge suctions and pump discharge valve are operatedlocally in the same compartment.

Under normal circumstances, the bilge water is pumped directly to the engineroom primary bilge tank, having first installed a spool piece in the line on deck.The bilge wells in the electric motor room are drained directly to the main deckbelow the cargo machinery room, via valve BC505.

Operation to Pump out Bilges from the Cargo Machinery Room

It is assumed that the bilge wells are inspected on a regular watch basis for anyaccumulation of liquid and that if any leaks are found, appropriate steps aremade to restrict/stop them, informing the officer of the watch of any actionstaken and of the conditions present. The bilge float alarms are tested on aregular planned maintenance schedule.

a) Install the spool piece on deck before isolating valve BC509.

b) Ensure that there is general service air on deck.

c) Connect the flexible air hose to the pneumatic bilge pump.

d) Open the required bilge suction valve.

e) Open the pump discharge isolating valve.

f) Open the deck isolating valve, discharging to the engine room.

g) When the bilge hat is empty, make a visual inspection of the floatand clear away any debris.

h) On completion, shut off the air supply, close the bilge suction,pump discharge and deck isolation valves, then remove the spoolpiece.

Issue: 1 5.7 Deck Scupper and Bilge System Page 2 of 2


Pneumatic Bilge Pump in the Cargo Machinery Room

Cargo Machinery Room Bilge Pump DischargeConnection to the Engine Room

Part 6Cargo Operations

Issue: 1 6.1 Insulation Space (IBS/IS) Nitrogenation Page 1 of 2

Tank 1

Tank 2

Tank 3

Tank 4

To No 3 TankInsulation Space



Inter BarrierSpace

InsulationSpace


No 1 Cofferdam

No 4 Cofferdam

No 2 Cofferdam

No 5 Cofferdam

CN051 CN052

CN053

CN054

CN426

CN425

CN424

CN415

CN416

CN417

CN326

CN226

CN126

CN315

CN316

CN318

CN317

CN215

CN216 CN218

CN217

CN115

CN116 CN118

CN117

CN419

CN421

CN407

CN309 CN307

CN409 CN411

CN405

CN428

CN328

CN228

CN128

CN305

CN311

CN209

CN205

CN211

CN406

CN412 CN410

CN408

CN312 CN310

CN308

To SprayLine

CN321

CN221

CN121

To SprayLine

CN418

CN055 CN056

Illustration 6.1a Insulation Space (IBS/IS) Nitrogenation

Key

Nitrogen Supply ToInsulation Spaces

Nitrogen Supply ToInter Barrier Spaces

CN427

CN327

CN227

CN127

CN325

CN324

CN225

CN224

CN125

CN124

No 3 Cofferdam

CN319

CN219

CN119

CN306

CN212 CN210

CN208

CN206

CN112 CN110

CN108

CN106

CN207

CN109

CN105

CN111

CN107

CN802

To Motor RoomFor HD and LD

CompressorBulkhead Sealing

To Cargo Machinery RoomFor HD and LD Compressor

Shaft Sealing

CN801

To SprayLine

To SprayLine


6.1 Insulation Space Inerting

The interbarrier space (IBS) and insulation spaces (IS) are filled with drynitrogen gas. This is automatically maintained by alternate relief and make-up,as the atmospheric pressure of the temperature rises and falls, under a pressureof between 0.6 and 0.8 kPa above atmospheric.

The nitrogen provides a dry and inert medium for the following purposes:

To prevent formation of a flammable mixture in the event of a LNG leak

To permit easy detection of a LNG leak through a barrier

To prevent corrosion

Nitrogen produced by generators and stored in a pressurised buffer tank issupplied to the pressurisation headers through make-up regulating valves.

From the headers, branches are led to the inter-barrier and insulation spaces ofeach tank. Excess nitrogen is vented through regulating relief valves to thenitrogen vent mast on each tank from the IBS and to deck from the IS.

Both IBS and IS of each tank are provided with pressure relief valves whichopen at a pressure, sensed in each space, of 3.0 kPa for the IBS and 3.5 kPa forthe IS above atmospheric. A manual bypass with a globe valve is provided forlocal venting and sweeping of a space if required.

The nitrogen production plant is maintained in an automatic mode. One 90m3/hpackage is able to maintain the pressure in the buffer tank owing to the smalldemands placed upon the system. When a high nitrogen demand is detected,the second 90m3/h package will start automatically. (See section 5.2.)

Operating Procedure for Normal Inerting(see illustration 6.1.a)

a) Adjust the set point of the nitrogen supply regulating valvesCN116, 216, 316, 416 to the IBS header and CN125, 225, 325,425 to the IS header at 0.6 and 0.8 kPa gauge respectfully.

b) Adjust the set point of the nitrogen exhaust regulating valvesCN109, 209, 309, 409 (IBS) and CN110, 210, 310, 410 (IS) at1.15 and 1.95 kPa gauge respectfully.

Ensure that the manual isolating valves situated each side of the control valve,both supply and exhaust on each tank are open, e.g. CN117 and CN 115 forNo.1 tank IBS supply.

c) Open the manual isolating valves CN054 and CN056 on theinsulation space pressurisation header and set the control valveCN055 to 2.0 kPa, to allow supply of nitrogen to the headers fromnitrogen buffer tank in engine room.

In the event of cargo gas leakage into insulation spaces, this can be swept witha continuous feed of nitrogen by opening the exhaust from the space, allowinga controlled purge. Close monitoring of the gas analyser on this space will benecessary during purging.

! CautionThe insulation spaces must at all times be protected against over pressure,which might otherwise result in membrane failure.

A portable elbow bend can be connected to the IBS supply header forconnection to the spray line for IBS stripping if required.

6.1.1. In Service Tests

Classification society regulations require that the barriers of a membrane tankshould be capable of being checked periodically for their effectiveness. Thefollowing covers the practice, recommendations and the precautions, whichshould be taken during the in-service periodical examination of the inter-barrier and insulation membranes.

Method for Checking the Effectiveness of the Barriers

IBS Membrane Each IBS space is provided with a permanently installed gas detection systemcapable of measuring gas concentration at intervals not exceeding thirtyminutes. The results of this monitoring give a continuous indication of themembrane tightness; any gas concentration in excess with regard to the steadyrates would be the indication of membrane damage.

Depending on the degree of leakage the gas concentration can be controlled bypurging with nitrogen or alternatively it may be necessary to take the vessel outof service to effect repairs.

IS Membrane The insulation space is monitored in the same manor and the same proceduresfor purging as per the IBS would be carried out.

Issue: 1 6.1 Insulation Space (IBS/IS) Nitrogenation Page 2 of 2


Issue: 1 6.2 Post Dry Dock Operation Page 1 of 10

Key

Illustration 6.2.1a Drying Cargo Tanks

Wet Air

Dry Air

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

CL200

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


6.2 Post Dry Dock Operation

6.2.1 Drying Cargo Tanks

During a dry docking or inspection, cargo tanks which have been opened andcontain wet air must be dried to avoid primarily the formation of ice when theyare cooled down and secondly the formation of corrosive agents if the humiditycombines with the sulphur and nitrogen oxides which might be contained inexcess in the inert gas. The tanks are inerted in order to prevent the possibilityof any flammable air/LNG mixture. Normal humid air is displaced by dry-air.Dry-air is displaced by inert gas produced from the dry-air/inert gas plant.

The inert gas is primarily nitrogen and carbon dioxide, containing less than 1%oxygen with a dew point of -45°C or below.

! WarningInert gas from this generator and pure nitrogen will not sustain life. Greatcare must be exercised to ensure the safety of all personnel involved withany operation using inert gas of any description to avoid asphyxiation dueto oxygen depletion.

Dry-air is introduced at the bottom of the tanks through the filling piping. Theair is displaced from the top of each tank through the dome and the vapourheader, and is discharged from the vent mast No.1.

The operation, carried out at shore or at sea, and will take approximately 40hours to reduce the oxygen content to less than 2% and the final dew point to-40°C.

During the time that the inert gas plant is in operation for drying and inertingthe tanks, the inert gas is also used to dry (below -40°C ) and to inert all otherLNG and vapour pipework. Before introduction of LNG or vapour, pipeworknot purged with inert gas must be purged with nitrogen.

Operating Procedure for Drying Tanks(see illustration 6.2.1a)

Dry-air, with a dew point of -45°C, is produced by the dry-air/inert gas plantat a flow rate of 14,000 Nm3/h.

a) Prepare the dry-air/inert gas plant for use in the dry-air mode.

b) Install the elbow to connect the outlet of the heaters with the LNGheader.

c) Open the valves CL702, CL410, CL310, CL210 and CL110 tosupply dry-air to the LNG header.

d) Open tank filling valves CL400, CL300, Cl200 and CL100.

e) Open tank vapour valves CG470, CG370, CG270, CG170.

f) Open CG471, CG371, CG271 and CG171 to vent through themast No.1. Eventually, tank pressure is controlled via theregulating valve CG771 set at 10kPa auto.

g) Start the dry-air production.When dew point is 45°C, open thevalve to deck upstream of the two non-return valves on the dry-air/inert gas discharge line.

h) Monitor the dew point of each tank by taking a sample at thevapour domes. When the dew point is -25°C or less, close thefilling and vapour valves of the tank.

Wet air which may be contained in the discharge lines from the cargo pumps,float level piping and any associated pipe work in the cargo compressor roommust be purged with dry-air.

i) When all the tanks are dried, stop the plant. Close the supplyvalve CL702 to the LNG header and close valve CG772 to theventing system at the mast riser No.1.

(Note ! It is necessary to lower the tank’s dew point by dry air to at least -25°C,before feeding tanks with inert gas in order to avoid formation of corrosiveagents.)




Illustration 6.2.2a Inerting Cargo Tanks Prior to Gassing-up

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

CL200

CL110

Key

Inert Gas

Dry Air

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


6.2.2 Inerting Cargo Tanks(see illustration 6.2.2a)

Inert gas, with an oxygen content less than 1% and a dew point of -45 °C, isproduced by the dry air/inert gas plant with a flow rate of 14,000 Nm3/h.

Emergency pump wells have to be inerted with nitrogen before inerting thecargo tanks.

a) Prepare the dry air/inert gas plant for use in the inert gas mode.

b) Install the elbow, to connect the outlet of the heaters with theLNG header.

c) Open the valves CL702, CL410, CL310, CL210 and Cl110 tosupply inert gas to the LNG header.

d) Open tank filling valves CL400, CL300, CL200 and CL100.

e) Open tank vapour valves CG470, CG370, CG270 and CG170.

f) Open CG471, CG371, CG271 and CG171 to vent through themast No.1. Eventually, tank pressure is controlled via theregulating valve CG771, set at 10kPa gauge. auto.

g) Start the inert gas production. When oxygen content is less than1% and the dew point is -45 °C, open the valve upstream of thetwo non-return valves on the dry-air/inert gas discharge line.

h) By sampling at the vapour dome, check the atmosphere of eachtank by means of the portable oxygen analyser. O2 content is to beless than 2% and the dew point less than -40°C.

i) During tank inerting, purge for about 5 minutes the air containedin the lines and equipment by using valves and purge samplepoints.

j) When the inerting of the tanks, lines and equipment is completed,set the regulating valve CG771 to 15kPa in order to pressurise allthe tanks to this pressure.

k) When the operation is completed, stop the supply of inert gas andclose the valves CL702, CL410, CL400, CL310, CL300, CL210,CL200, CL110 and CL100 and remove the elbow piece.

(Note ! Until the ship is ready to load LNG, the tanks maybe maintained underinert gas as long as necessary. If required, pressurise the tanks 2kPa aboveatmospheric pressure and to reduce leakage, isolate all the valves at theforward venting system.)




Key

Illustration 6.2.3a Gassing Up Cargo Tanks

LNG Liquid

Inert Gas

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CL400

CS067

CS065

CS063

CS061

CS754

CS752

CG872

CG918

CS951

CS902

CS901

CL041CL031

CL021CL011

CL200

CL110

CL700

CS068

CS066

CS064

CS062

CL042

CL022

CL032

CL012

CG922

CG921

CS750

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


6.2.3 Gassing-Up Cargo Tanks

Introduction

After lay up or dry dock, the cargo tanks are filled with inert gas or nitrogen.If the purging had been done with inert gas when the vessel arrived at theloading terminal the cargo tanks have to be purged and cooled down.

This is because, unlike nitrogen, inert gas contains 15% of carbon dioxide(CO2), which will freeze at around -60°C and produces a white powder whichcan block valves, filters and nozzles.

During purging, the inert gas in the cargo tanks is replaced with warm NGvapour.

This is done to remove any freezable gases such as carbon dioxide and tocomplete the drying of the tanks.

Operation

LNG liquid is supplied from the terminal to the liquid manifold where it passesto the stripping/spray header via the appropriate ESDS liquid valve.

It is then fed to the main vaporizer and the LNG vapour produced is passed at+20°C to the vapour header and into each tank via the vapour domes.

At the start of the operation, the piping system and main vaporizer are vapourlocked. The stripping/spray header can be purged into the cargo tanks via thevapour dome through the arrangement of spray valves containing the controlvalve until liquid reaches the main vaporizer. The LNG vapour is lighter thanthe inert gas, which allows the inert gases in the cargo tanks to be exhaustedup the tank loading column to the liquid header. The inert gas then vents to theatmosphere via the No.1 mast riser.

When 5% methane (% figure will be specified by the particular port authority)is detected at No.1 mast riser, the exhaust gas is directed ashore via the HDcompressors, or to the boilers through the gas burning line.

This operation can be done without the compressors, subject to existing backpressure, or with one or both HD compressors in service.

If possible, it is better not to use compressors to avoid creating turbulenceinside the tanks.

The operation is considered complete when the methane content, as measuredat the top of the cargo filling pipe, exceeds 80% by volume.

This normally entails approximately 1.5 changes of the volume of theatmosphere in the cargo tank.

On completion of purging, the cargo tanks will normally be cooled down.

There are exceptional cases where it may be necessary to undertake thepurging of one or more tanks at sea using LNG liquid already on board.

In this case the liquid will be supplied to the main vaporizer via thestripping/spray header using the stripping/spray pump of a cargo tankcontaining LNG liquid.

Due to local regulations on venting methane gas to the atmosphere, some portauthorities may require the entire operation to be carried out with the exhaustgases being returned to shore facilities.

Operating Procedures to Purge the Cargo Tanks with LNG VapourStage One (See Illustration 6.2.3a)

It is assumed, though unlikely, that all valves are closed prior to use.

a) Install the following removable bends:

Liquid header to compressors (only if compressors are required).

Liquid header to No.1 mast riser.

b) Prepare the main vaporizer for use.

c) Adjust the set point of temperature control valve to +20°C.

d) Using the IAS adjust the set point of the pressure control valve to6kPa (or required value).

e) At No.1 mast riser open valve CL700.

f) Open CS750, the stripping/spray header crossover valve to themanifold.

g) Open CS754 and CS752 on the stripping/spray header to enablesupply to reach the main vaporizer.

h) Open CS951, the inlet valve to the main vaporizer.

i) In the cargo machinery room open the outlet from the mainvaporizer CG918.

j) Open CG872 to allow supply to the vapour header.

k) Open header valves to vapour domes.

No.1 Tank CG170, 90% CG171, full open




For safety reasons, ensure that the hull water curtain on the connected side isin operation.

l) Open CS067 (if using the aft liquid manifold on the port side), theisolating valve to the stripping/spray line.

m) Using the IAS open the individual tank loading valves.

No.1 Tank CL100 CL110



No.4 Tank CL400 CL 410

n) Using the IAS, open CL041, the aft liquid manifold valve on theport side, and request the terminal to commence supply of LNGliquid to the ship at a constant pressure of 500kPa.

o) Adjust No.1mast riser pressure with CG771 at 23kPa or asrequired.

p) Monitor the inert exhausting gas at each liquid dome using themid cargo tank sample cock initially, followed by the sample cockat the top of the loading line. Also monitor the inert exhausted gasat No.1 mast riser, using the sample cock.

q) When 5% methane, (or the quantity the port authority will allow)is detected at No.1 mast riser and each vapour dome, requestpermission from the terminal personnel to direct exhaust gas tothe terminal facilities. If this is not possible, direct gas to theboilers through the gas burning header, by opening valve CG921and CG922 and closing valve CL700 if returning gas to theterminal.




Key

Illustration 6.2.3b Gassing Up Cargo Tanks Return to Terminal

LNG Liquid

LNG/Inert Gas Mixture

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CL400

CS067

CS065

CS063

CS061

CS754

CS752

CG872

CG918

CS951

CS902

CS901

CL041CL031

CL021CL011

CL200

CL110

CL700

CS068

CS066

CS064

CS062

CL042

CL022

CL032

CL012

CG922

CG921

CL700

CL702

CG900

CG874

CG910

CG912

CG909

CG907

CG772

CG771

CG071

CS750

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


The second stage of the procedure is to bring the methane content inside thetanks up to 80%methane utilising the HD compressors.

(See illustration 6.2.3b)

a) Prepare both HD compressors for use.

b) Install the elbow connecting the liquid line to the suction for theHD compressors.

c) Adjust the set point of both HD compressors pressure controlvalve to 6kPa (or the required value).

d) On the HD compressors open the following valves:

CG907 Inlet to No.1 HD compressor

CG909 Outlet from No.1 HD compressor

CG910 Inlet to No.2 HD compressor

CG912 Outlet from No.2 HD compressor

e) Open the following valves:

CG874, CL702 Liquid header vapour supply to the HD compressors

CG900 Compressor supply to the manifold

f) Open the vapour manifold valve CG071 (port side). This willenable a free flow of gas to the terminal and is a check that thepipeline layout on board has been arranged correctly.

g) Once the flow to the terminal has been established, close valveCL700 at No.1 mast riser. Using the IAS, adjust the set point ofNo.1 mast riser control valve CL771 to the required value Forexample 23kPa, so that this valve will remain closed duringnormal running of the compressors, but would act in a safetycapacity if necessary, and open CL772.

h) If the tank pressure increases too much, using the IAS start one orboth of the compressors as necessary.

i) Using the IAS, monitor the pressure inside the tanks.

If the pressure increases, request the terminal to reduce the supply of LNG, orincrease the flow through the HD compressor by adjusting the set point on bothHD compressor control valves.

If the pressure decreases, reduce the flow through the HD compressors byadjusting the set point of both HD compressors by the control valve.

Alternatively, shut down one of the compressors as necessary, or request theterminal to increase the LNG liquid supply to the main vaporizer.

When the cargo tank methane content reaches 80%, throttle in the individualtank loading valve until it is only just cracked open.

During the change of atmosphere purge the following sections for about 5minutes each:

a) All sections of the stripping/spray header and tank connections,via the valves at each vapour dome.

No.1 Tank CS156, 151, 152

No.2 Tank CS256, 251, 252

No.3 Tank CS356, 351, 352

No.4 Tank CS456, 451, 452

b) Purge manual and ESD valves, the manifold bypass valves are notin use.

The operation is considered complete when all four cargo tanks have at leastan 80% methane content and the acceptable CO2 content as requested by theterminal.

c) Purge the following lines and equipment for five minutes each:

No.1 and 2 boil off/warm up heater, forcing vaporizer, venting via the samplingcocks.

HD and LD compressors with the compressor inlet and outlet valves. Makesure to thoroughly purge each compressor in turn.

Vapour crossover and manifolds CG077 and CG078, venting through themanifold flanges CG071 and CG072.

Cargo pump lines and auxiliary cargo pump well via the appropriate line valveand purge sample point.

Extremities of vapour header via sample points.

d) Request the terminal to stop the supply of LNG liquid.

e) Stop both HD compressors.

f) Close CS754, the isolating line to the stripping/spray lines.

g) Do not shut down the main vaporizer until it has been warmedthrough to the ambient temperature.

h) Remove and blank removable bends after purging with nitrogenand testing the gas content.

i) Prepare the cargo system for cooldown.




Key

Illustration 6.2.4a Cooling Down of Cargo Tanks After Gasing Up

LNG Liquid

LNG Vapour

H

H

H

H

H

CL410

CL400

CS067

CS065

CS063

CS061

CS752

CG918

CS951

CS902

CS901

CL041CL031

CL021CL011

CL200

CL110

CS068

CS066

CS064

CS062

CL042

CL022

CL032

CL012

CG922

CG921

CL702

CG900

CG874

CG910

CG912

CG909

CG907

CG071

CS750

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100

CS751

CS252

CS255

CS152

CS155

CS352

CS355

CS452CS455


6.2.4 Cooling Down Cargo Tanks

Introduction

Arriving at the loading terminal to load the first cargo after refit or whenrepairs requiring the vessel to be gas free, the cargo tanks will be inert and atambient temperature. After the cargo system has been purge-dried and gassedup, the headers and tanks must be cooled down before loading can commence.The cooldown operation follows immediately after the completion of gassingup, using LNG supplied from the terminal.

The rate of cooldown is limited for the following reasons:To avoid excessive pump tower stress.Vapour generation must remain within the capabilities of the HDcompressors to maintain the cargo tanks at a pressure of 7kPa(about 108.5kPa abs). To remain within the capacity of the nitrogen system to maintainthe interbarrier and insulation spaces at the required pressures.

Unlike rigid cargo tank designs, vertical thermal gradients in the tank walls arenot a significant limitation on the rate of cooldown.

LNG is supplied from the terminal to the cooldown bobbin piece and fromthere directly to the spray header which is open to the cargo tanks. Once thecargo tank cooldown is nearing completion, the liquid manifold crossovers,liquid header and loading lines are cooled down.

Cooldown of the cargo tanks is considered complete when the top (T1) andbottom (T6) temperature sensors in each tank indicate temperatures of -130°Cor lower. When these temperatures have been reached, and the Foxboro CTSregisters the presence of liquid, bulk loading can begin.

Vapour generated during the cooldown of the tanks is returned to the terminalvia the HD compressors and the vapour manifold as in the normal manner forloading.

During cooldown, nitrogen flow to the IBS and IS spaces will significantlyincrease. It is essential that the rate of cooldown is controlled so that it remainswithin the limits of the nitrogen system to maintain the interbarrier andinsulation space pressures at 0.8kPa and 1.0kPa respectively.

Once cooldown is completed and the build up to bulk loading has commenced,the tank membrane will be at or near to liquid cargo temperature, it will takesome hours to establish fully cooled down temperature gradients through theinsulation. Consequently boil-off from the cargo will be higher than normal.

Cooling down the cargo tanks from +30°C to -130°C, over a period of 8 hourswill require a total of about 600m3 of LNG to be vaporized. At a mean coolingrate of 30°C per hour over the first 4 hours, this should correspond to a meancooling rate of 12°C to 13°C per hour for the secondary barrier, giving atemperature of approximately -80°C after 8 hours.

Preparation for Tank Cooldown

Place in service the heating system for the cofferdams.

a) Prepare the records for the tank, secondary barrier and hull tem-peratures.

b) Check that the nitrogen pressurisation system for the insulationspaces is in automatic operation and lined up to supply theadditional nitrogen necessary to compensate for the contractionfrom cooling of the tanks. Prior to the cooling down, the nitrogenpressure inside the primary insulation spaces will be raised to0.8kPa. Pressurise the buffer tank at maximum pressure.

c) Check that the gas detection system is in normal operation.

d) Prepare the nitrogen generators for use.

e) Prepare both HD compressors for use.

Operating Procedure - Gas Return Through LNG Header (See illustration 6.2.4a)

Assuming the ship to be at the ready to prepare for cooldown after thecompletion of gassing up.

As reported by several ship operators, it seems accepted that the vapour returnthrough the LNG header instead of the vapour header, makes the cooldownoperation more efficient and prevents liquid droplets in the vapour stream.

On the suction side of the HD compressor(s) from the LNG header, the linesare arranged as follows:

a) Install the elbow, connecting the liquid line with the suction sideof the HD compressor, open the valve CL702 from the LNGheader. Open CG874 connecting the crossover suction to theelbow.

b) Open the inlet and outlet valves of the compressors, No.1 CG907, 909, No.2 CG910, 912.

c) Open the valve CG900 HD compressor discharge to the vapourmanifold.

d) Open the filling valve on each tank CL100, 200, 300, 400.

e) Open the vapour valves on each tank CG171,170, CG271, 270,CG371, 370, CG471, 470. All the tanks are kept connected to thevapour header.

f) At the vent mast No.1, open CL772.

g) Set the pressure control valve CG771 at 10kPa to avoid venting,except for safety.

h) Open one spray valve on each tank dome, CS152, CS252, CS352,CS452.

i) Request the terminal to supply LNG liquid for the cooling downoperation at minimum flow.

j) When the vapour pressure inside the tanks rises to approximately6kPa, start the first compressor and increase the spray nozzlepressure to 200kPa.

k) Monitor the tank pressure and temperature cooldown rate. Adjustthe opening of the spray inlet valves CS155, 255, 355 455 toobtain an average temperature fall of 25/30°C per hour during thefirst 4 hours. Thereafter 12/13°C per hour.

l) Start the second HD compressor if required.

This procedure will normally take approximately 10/12 hours.



6.3 Ballast Voyage

A characteristic of the cargo tanks of the Gaz Transport Mark III membranetype is that as long as some quantity of LNG remains at the bottom of the tanks,the temperature at the top will remain below -50°C.

However, if the ballast voyage is too long, the lighter fractions of the liquidwill evaporate. Eventually most of the methane disappears and the liquidremaining in the tanks at the end of the voyage is almost all LPG with a hightemperature and a very high specific gravity, which precludes pumping.

Due to the properties of the materials and to the design of the membrane cargocontainment, cooling down prior to loading is, theoretically, not required forthe tanks. However, to reduce the vapour generation and to prevent anythermal shock on the heavy structures, e.g. the pump tower, loading takes placewhen the tanks are in a cold state.

Cold Maintenance During Ballast Voyage

Different methods are used to maintain the cargo tanks cold during ballastvoyages:

1) For short voyages a sufficient amount of LNG is retained in each tank at theend of discharge. The level must never be above 10% of the length of the tankand the quantities can be calculated by considering a boil-off of approximate-ly 0.18% per day and the need to arrive at the loading port with a minimumlayer of 10cm of liquid spread over the whole surface of the tank bottom (withthe ship on an even keel).

These actual quantities will have to be confirmed after a few voyages.

With this method of cold maintenance, the tank bottom temperature should bebelow -150°C and the top below -50°C, which allows loading without furthercooling down.

2) During longer ballast voyages, the lighter parts of the liquid layer remainingin the tank, will evaporate, thus making the liquid almost LPG and at temper-atures of higher than -100°C. The upper parts of the tanks will reach almostpositive temperatures and under these conditions it will be necessary to cooldown the tanks before loading.

Three methods of cooling down are possible, and the one selected will dependon the operating conditions of the ship.

a) Cool down the tanks with LNG supplied from shore as in section6.2.4.

b) Cool down the tanks just before arrival at the loading terminal. Atthe previous cargo discharge, a LNG heel is retained in one of thetanks, provided that the heel does not exceed 10% of the tanklength (see sloshing). On top of the quantity to be sprayed, theamount of the LNG heel to be retained will be calculated byassuming a boil off equivalent of 50% of the boil off under ladenconditions.

c) Maintain the cargo tanks at cold during the ballast voyage by peri-odically spraying the LNG so that the average temperature insidethe tanks does not exceed -120°C/-130°C. As before, a LNG heelis kept in one of the tanks, provided that the level does not exceed10% of the tank length (see sloshing). On top of the quantity to besprayed, the amount of the LNG heel that needs to be retained willbe calculated by assuming a boil-off equivalent of 50% of the boiloff under laden conditions.

Cooling down is carried out by spaying LNG inside the tanks for whichevermethod is used. Each tank is provided with two spray rings.

(Note! It is obvious that this system will generate more boil-off than the firstproposed system. The quantity of LNG to be retained on board will have to becalculated with enough margin to avoid the situation at mid-voyage where theresidual is too heavy for the pump to operate.)

Conservation of bunkers is important, consequently, the co-operation of allmembers of the management team is essential to ensure as much boil-off gasas possible is used to supply boiler fuel demand, thus keeping fuel oilconsumption to a minimum.

The LD gas compressor is used for gas burning on the ballast voyage in thesame way as on loaded voyage, with control of the compressor from vapourheader pressures (see section 6.5 Gas Burning Operation).

If a long delay at the loading port is experienced, the remaining heel willslowly boil-off and the gas available for burning will reduce. Therefore, caremust be taken to stop gas burning as the tank system pressures continue to dropas the temperature rises. The degree of natural warm-up will depend on thetime factor, voyage and weather conditions.

After refit, the first ballast voyage will have to be made using fuel oil only.

Due to the different calorific values of fuel oil and gas, engine power willrequire controlling to prevent overloading the boilers.

Issue: 1 6.3 Ballast Passage Page 1 of 5



Key

Illustration 6.3.1a Cooling Down Tanks Prior to Arrival on Ballast Voyage

LNG Liquid

LNG Vapour

H

H

H

H

H

CS752

CG170

CG171

CG470

CG471

CS751

CS252

CS255

CS152

CS155

CS352

CS355

CS452CS455

CS450

CS354

CS254

CS154

CG875

CG913

CG904

CG901

CG906

CG903

CG914

CG873

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid Dome

CG370

CG371

CG270

CG271


6.3.1 Cooling Down Tanks Prior to Arrival(See illustration 6.3.1.a)

It is assumed all valves are closed prior to use and a heel for cooldown hasbeen retained in No.4 cargo tank, all other tanks have been allowed to warmup due to the length of the voyage.

Set the forward mast riser setpoint to 115kPa abs. and the LD compressor(s)on line to supply the engine room with boil-off gas for the boilers.

Set the nitrogen system to high flow operation.

Set the supply valve CN055, nitrogen to insulation space header, at 2.0kPagauge.

Set the set point on the insulation barrier space exhausts to 1.15kPa gauge.

Set the set point on insulation space exhausts to 1.95kPa gauge.

As the insulation barrier space and insulation space spaces cool down, the setpoints can be lowered accordingly.

a) Open the vapour dome outlet valves to the vapour header CG170,171, 270, 271, 370, 371, 470 and 471.

b) Open the valves on the spray line header CS155, 255, 355, 455,751 and 752.

c) Open the spray inlet valve to No.4 tank CS452.

d) Partially open the spray inlet valves to No.1, 2, and 3 tanksCS151, 152, 252 and 352.

e) Start No.4 spray pump and open the spray discharge valve CS450to allow minimum flow and to cool down the spray header.

f) Once cooldown of the spray header to No.4 tank is complete, shutin on CS452 to allow the remainder of the spray line to cool-down.

Care should be taken to maintain control of vapour pressure either by use inthe boilers as fuel, or vent to atmosphere via the forward riser.

g) Once all spray headers are cool, increase flow by adjusting thespray pump discharge valve and flow to the tanks to maintain aneven cooldown and control of vapour pressure.

h) When all the tanks have attained the required temperature (-100°Cat top, -130°C at bottom) either continue to spray tanks until the

required heel is transferred or as follows:

i) Open the spray line drain lines on No.1, 2 and 3 tanks, valvesCS154, 254 and 354 and transfer the required amount of heel toeach tank.

j) On completion of cooldown, leave the spray header valves opento allow the spray line to warm up to the ambient temperaturebefore closing them.

k) Reset the nitrogen supply system to normal operating set points.




Key

Illustration 6.3.1.1b Cooling Down One Tank Prior to Arrival on Ballast Voyage

LNG Liquid

LNG Vapour

H

H

H

H

H

CG170

CG171

CG470

CG471

CS452CS455

CS450

CG875

CG913

CG904

CG901

CG906

CG903

CG914

CG873

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid Dome

CG370

CG371

CG270

CG271


6.3.1.1 Spraying During Ballast Voyage, Single Tank(See illustration 6.3.1.1b)

Assuming a single tank (No.4 tank) is to be cooled down using heel in thattank.

It is assumed all valves are closed prior to use.

Set the forward mast riser set point to 115kPa abs. and the LD compressor(s)on line to supply the engine room with boil-off gas for the boilers.

Set the nitrogen system to high flow operation.

Set the supply valve CN055, nitrogen to insulation space header, at 2.0kPagauge.

Set the set point on the insulation barrier space exhausts to 1.15kPa gauge.

Set the set point on the insulation space exhausts to 1.95kPa gauge.

As the insulation barrier space and insulation space spaces cool down the setpoints can be lowered accordingly.

a) Open the vapour dome outlet valves to the vapour header CG170,171, 270, 271, 370, 371, 470 and 471.

b) Partially open the spray inlet valve to No.4 tank CS452.

c) Start No.4 spray pump and open the spray discharge valve CS450to allow minimum flow and to cool down the spray header.

d) Once cooldown of the spray header to No.4 tank is complete,open up CS452 and increase the flow rate by adjusting the spraypump discharge valve to allow an even cooldown and control ofvapour pressure.

Care should be taken to maintain control of vapour pressure either by use inthe boilers as fuel or venting to atmosphere via the forward riser.

e) On completion of cooldown, leave the spray header valves opento allow the spray line to warm up to the ambient temperaturebefore closing them.

f) Reset the nitrogen supply system to normal operating set points.

The above operation can be repeated for each individual tank.

Sloshing

From the experience gained on the first LNG ships put into service and from alarge number of model tests and computer analyses, Gaz Transport havedesigned new tanks which are reasonably free from any sloshing risk.

The ship’s cargo tanks are designed to limit the impact forces and the safetymargin has been considerably enlarged. However, operators should be alwaysbe aware of the potential risks to the cargo containment system and also on thetank equipment due to sloshing.

Precautions to Avoid Damage due to Sloshing

Cargo tank levels:

The first precaution is to maintain the level of the tanks within the requiredlimits i.e.:

Lower than a level corresponding to 10% of the length of the tank

or,

Higher than a level corresponding to normally 80% of the height of thetank.

Ship’s movement:

The second precaution is to try to limit the ship’s movement, which wouldgenerate sloshing in the tanks.

The amplitude of sloshing depends on the condition of sea (wave pattern), thetrim and the speed of the ship.



Issue: 1 6.4 Loading Page 1 of 6

Illustration 6.4.2a Liquid Line Cooldown Before Loading

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

Key

LNG Vapour

LNG Liquid

CL110

CS156 CS154

CL041CL031

CG071

CL021CL011

CL013CL023

CL033CL043

CS456CS454

CS058

CS068

CS056

CS066CS054

CS064

CS052

CS062

CL042

CL044CL034

CL022CG072

CL032

CL012

CL024 CL014

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid Dome


6.4 Loading

Introduction

After cooldown is completed, the vessel is ready to load LNG. The cargo tanksare loaded simultaneously and deballasting is carried out at the same time.

Loading is complete when all tanks are 98.5% full by volume.

During loading the boil-off and displaced gas is returned to shore facilities. Itwill normally be necessary to use either one HD compressor whilst loading toreduce and maintain the cargo tank pressure to the required pressure of 2.3kPa.

Operation

LNG is loaded via the loading manifolds to the liquid header and then to eachtank filling valve.

The boil-off and displaced vapour leave each tank via the gas domes to thevapour header. The vapour is initially free-flowed to shore via the vapourcrossover manifold and, as tank pressure rises, one compressor is brought intooperation to increase the gas flow to shore and limit the vapour main and hencecargo tanks pressure.

Deballasting is undertaken at the same time as cargo loading and the debal-lasting sequence is arranged to keep the vessel within the required limits ofdraught, trim, stress and stability.

Deballasting takes normally about 12 hours and so will be completed shortlybefore the end of loading.

If necessary, the flow of nitrogen to the IBS is increased to maintain a positivepressure in these spaces during completion of cooldown and start of loading.This is achieved by increasing the pressure in the IBS and IS to 0.9 and 1.0kParespectively.

The cofferdam heating system is put into operation as soon as a stable loadingsituation is achieved.

On completion of loading, the liquid header and other liquid pipes are drainedto No 4 cargo tank. The liquid remaining in the inclined part of the liquidmanifolds is pushed in board using N2 pressure from shore and the loadingarms are then purged and disconnected. If the vessel is not sailing immediately,the vapour arm will remain connected in order to continue returning boil-off tothe shore.

6.4.1 Preparations for Loading

Loading is commenced after cooldown of the cargo piping with one of theshore pumps, with the ESDS manifold valves opened and manual double shutoff valves open and the vapour into tank No.4 and tank No.1 open via CS456,454 and CS156, 154. As the flow increases, adjust with tank No.4 and tankNo.1 vapour valve in order to ensure that all pipelines are full and cooled.

Once the ship and shore pipelines have cooled down (about 90 minutes), openall tank filling valves and commence loading at the agreed rate.

As the loading rate increases, it is important to monitor the evolution of thetank pressures and to start one HD compressor in order to limit the pressure to2.3kpa gauge. If the compressors are unable to cope with the volume of boil-off and displaced gas, it will be necessary to reduce the loading rate.

During the time of cooling down of the piping and the start of loading, it isimportant to patrol the whole deck area to monitor for all potential cargo leaks.All leaks, even the smallest one, must be corrected immediately even if thisrequires slowing down or even stopping the loading.

To Load Cargo with Vapour Return to Shore

It is assumed for clarity of the description that all valves are CLOSED prior touse and that the ship is port side alongside.

a) Checks to be made before cargo operation: test remote operationof all tank valves and manifold crossover valves.

Test the remote operation of ballast valves. Test the HDcompressors,ballast pumps, safety systems and bulkhead heatingsystems.

b) Safety precautions:Ensure that the hull water curtain is in operation on the port side.

Prepare fire fighting equipment, water hoses and protectiveclothing for use. In particular the manifold dry powder monitorsshould be correctly aligned ready for remote operation. Ensure thewater spray system on deck is ready for operation, filters installedand off shore blanks removed.

c) Prepare both HD compressors for use with seal gas and LOlsystem in operation. (See section 4.4.1)

d) Nitrogen system: Ensure that N

2storage tanks are at maximum pressure and that the

two N2

production plants are ready to operate. Adjust the pressureof IBS and IS insulation to 0.6 and 0.8kPa.

e) Switch on unblocking level alarms in the custody transfer systemand run a custody transfer print-out for official tank gauging.

6.4.2 Liquid Line Cooldown Before Loading(See illustration 6.4.2a)

a) Open the gas outlet valves on tank gas domes.

Tank No.1: CG170, CG171




b) On HD gas compressors open valves CG873, 910, 909, 912, 900.

c) Check the connection of liquid and vapour arms, communicationswith shore, ship/shore electrical and pneumatic connection andsafety devices ESDS. Carry out safety tours.

d) Complete the relevant ship/shore safety checklist.

When shore is ready to purge the manifold connections with nitrogen:

a) Open liquid manifold ESDS valves CL031, 021, 011. Purge theconnections and then close valves. Pressurise manifolds withnitrogen and leak test.

b) Open vapour manifold ESDS valve CG071.Purge the connection and then close valve CG071.Pressurise manifold with nitrogen and leak test.

c) Open liquid valves CL110, 210, 310, 410.Open vapour freeing lines into tank No.1 and No.4, valvesCS156, 154, 456, 454.

When it is agreed between ship and shore that the vessel is ready to cool down:

e) Open vapour manifold ESDS valve CG071.

f) At liquid manifoldOpen manual valves CS061, 761, 063, 763, 065, 765.Open ESD hydraulic valves CL011, 021, 031.

The shore will commence supplying LNG to the liquid manifold connectionsto cool down the loading arms and lines and will then slowly increase the rate,progressively filling up and cooling down the arms and liquid header to tankNo 4 and tank No 1.

g) When the main liquid header and shore line has completelycooled down (usually about 90 minutes) open manifold valvesCL013, 023, 033.




Illustration 6.4.3a Loading with Vapour Return to Shore Via HD Compressor

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CL400

Key

LNG Vapour

LNG Liquid

CS751

CL110

CG079

CL041CL031

CG071

CL021CL011

CL013CL023

CL033CL043

CL042

CL044CL034

CL022CG072

CL032

CL012

CL024 CL014

CL200

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100

CG900

CG910

CG912

CG909

CG907

CG873

CS750


Proceed as for loading (section 6.4.3). When the tank liquid filling valves areopened, valves CS156, 456 can be shut. Close CS154, 454 when these lineshave warmed up.

6.4.3 Loading(See illustration 6.4.3a)

a) Open filling valve of tank No.1 and tank No.4 fully, CL100 andCL400.Open filling valves of other tanks:Tank No.2: CL200, tank No.3: CL300.

b) Increase the loading rate. Shore will start a pump twenty minutesafter the first pump, thereafter a further 20 minutes, followed bya further twenty minutes. The last two pumps are then started inten minute intervals, unless a special request is made.

c) Start the deballasting programme. Keep draught, trim and hullstresses within permissible limits by controlling the deballasting.

d) Start the glycol water heating in the cofferdams.

e) Monitor the tank pressures in order to achieve a pressure of about2.1-2.3kPa gauge. Open valves CG873, 910, 907 vapour header tocompressors and valves CG909, 912 on the compressors’discharge side.

f) Start one or both HD compressors as necessary. Close valveCG079 vapour header to crossover.

g) Adjust the opening of the tank filling valves to maintain even dis-tribution.

h) Ease in the filling valve of each tank as the tank approaches fullcapacity. Arrange to terminate tanks at 15 minute intervals.

i) Level alarms. When any tank approaches 95% capacity informshore.Pre-high level alarm sounds at 97%/98%.Standby valve before level approaches 98.6%.High level alarm will sound at 98.6% capacity and filling valvewill automatically close.

Very high level alarm will operate at 99% capacity and will initiate theemergency shut down.

! WARNINGThe very high level alarms and shut downs are emergency devices onlyand should on no account be used as part of the normal topping-offoperation.

j) Before topping-off the first tank, request shore to reduce loadingrate and continue reducing when topping off each following tank.When a tank is at its required level, close the correspondingloading valve, tank No.1 CL100, tank No.2 CL200, tank No.3CL300. It is convenient to finish loading by tank No.4 for ease ofline draining.

k) Stop loading when the final tank reaches 98.6% capacity minus anallowance for line draining and leave the tank loading valve open (CL400). Final tank loading valve is put to manual operation tostop at 98.5% alarm, resulting in the valve closing.

l) Liquid lines, including the horizontal part of the manifolds, willautomatically drain to tank No.4. The inclined parts of themanifold are purged inboard with nitrogen.

m) On completion of draining loading arms close liquid manifoldESDS valves.The shore lines are now pressurised at 300kPa with nitrogen.

Open the manifold ESD valves to let liquid return to the horizontal part of thelines.

n) Close the ESD valves and repeat pressurisation and purgingthrough valves CS051, 061, 063, 065, 067. Repeat this operationthree or four times until no liquid remains in the manifold lines.

o) When there is no remaining liquid the manual double shut offvalves and ESD valves are opened and the bypass valves closed.The lines are vented with nitrogen pressure to blow hydrocarbongas from the ship.

When gas readings obtained from an explosimeter are less than 50% LEL atthe vent cocks, all valves are closed and the loading arms are ready to be dis-connected.

p) The HD compressors are kept running to maintain a low tankpressure while loading lines are purged. Leave the loading valveof tank No.4 CL410 and 400 open until the piping has returned toambient temperature.

q) Return the nitrogen system to normal flow.In the CACC ensure that the set point is at 0.6kPa and 0.8kPa.

r) Tank level alarms.Inhibit high level alarms prior to proceed to sea.

s) Complete the deballasting operation to obtain an even keelsituation for final measurement. When the measurement iscompleted adjust ballast tank levels for sailing condition.

t) Stop the HD compressors just before closing the vapour manifoldESDS valve CG071 for nitrogen purging and disconnection ofloading arms.

u) Close the vapour crossover valve CG079 and open the vapourmanifold ESDS valve CG071. Purge the connection with nitrogenand then close the valve.

v) Disconnect the vapour arms.

w) Prepare the cargo system for gas burning at sea.

x) Adjust the ballast for departure trim condition.

y) Open all valves to allow warming up. These are normally theloading valves, pump discharge valves and spray valves on thetank domes.







GS Pump

BA501

Fore PeakTank

BosunStore

BA502


BA032BA012

BA013

BA009

BA010

BA002

BA003

BA006

BA011

BA027

BA025

BA025

To I.G.Generator

WS118

WS117


3,000m3/h



Self Priming

BA026

BA029

BA031

BA513BA517BA5021


Key

Sea Water Ballast











ForwardBallast Tank

Port

Illustration 6.4.4a De-ballasting

Hydraulic Line

BA507

BA506

BA505WS172

BA001

BA008BA524

BilgeSuction

From PipeDuct

BA023

No.2 Eductor300m3/h

No.1 Eductor300m3/h

BA015

BA007

BA004



Low Suction


BA017

BA021

BA019

BA030

FD032 FD010 FD020

BA028

To/FromAft Peak

Tank


Emergency Use





BA020

BA016

PI PT PI

PI PT PI

PI

PI

LS ZI

LS ZI

LS ZI

PI

PI

PI PIPSPT

PI PIPSPT

PI PIPSPT

PI PT PI

PT

LIAH

BA12LIAH

BA10LIAH

BA08LIAH

BA06LIAH

BA09LIAH

BA11LIAH

BA07LIAH

BA05LIAH

BA04LIAH

BA03LIAH

BA02LIAH


6.4.4 Deballasting


It is assumed that the main sea water crossover pipe is already in use,supplying other sea water systems, e.g. the main circulating system, the seawater service system and that the cargo and ballast valve hydraulic system isalso in service.

To Deballast the Ship

By Gravity! Caution

Mal-operation of the ballast system will cause damage to the GRPpipework. Damage is generally caused by pressure surge due to suddenchanges in the flow rates. During the deballasting operation this can becaused by the opening of a full or partly full tank into the main lines whenunder vacuum.

Under no circumstances should a vacuum be drawn on a closed ballast main.

Before starting deballasting operations, the main lines must be purged of anyair pockets in the following manner.

a) Open the overboard discharge crossover line valves BA027,BA025 and overboard discharge valves BA026 and BA029, alsoBA008 and BA001 on the ballast water crossover line.

b) Open the ballast main outlet valves BA015, BA007.

c) Open the ballast main isolating valves BA032 and BA031.

d) Open the forward ballast tank valves port and starboardBA504, BA503, or No.1. ballast tanks port and starboardBA 509, BA 508, if the forward ballast tanks do not havesufficient head of water to gravity flow.

A flow will now be established.

e) Open the valves on the tank(s) to be emptied as per thedeballasting plan.

Forward port BA504

Forward starboard BA503

No.1 port BA509

No.1 starboard BA508

No.2 port BA513


No.3 port BA517


No.4 port BA521


When it becomes necessary to start the ballast pumps:

f) Open valves BA012, BA009, BA002.

g) Close valves BA015 and BA007.

h) Check that the ballast tank valves are open.

i) Start the ballast pump(s).

j) Open the pump(s) discharge valve BA014 (port), BA011 (centre),BA006 (starboard).

k) As the tank reaches the required level, open the valves on the nexttank before closing the valves on the first tank.

l) When the suction has been lost on all tanks, close the dischargevalves on the pumps BA014 (port), BA011 (centre), BA006(starboard) and stop the pumps.

m) Close the tank valves, isolating main valves BA032, BA031,ballast crossover valves BA001, BA008, discharge crossovervalves BA027, BA025 and the overboard discharge valvesBA026, BA029.

n) Strip the ballast tanks as required (see below).

To Strip the Ballast Tanks Using a Ballast Eductor

Using the water spray pump

a) Open the eductor drive water overboard discharge valve BA030.

b) Open the eductor(s) discharge valves BA019 (No.1) BA023(No.2).

c) Open the drive water supply from the water spray pump, valvesBA021 (No.1) and BA017 (No.2).

d) Open the valve on first tank to be stripped.

Forward port BA507


No.1 port BA511


No.2 port BA515


No.3 port BA519


No.4 port BA523


e) Open the eductor suction valves BA020 (No.1) BA016 (No.2).

f) When one tank has been stripped, ensure the next tank valve isopened before closing the previous tank.

g) When all tanks have been stripped, close the eductor suctionsBA020 (No.1) BA016 (No.2).

h) Close the eductor drive water valves BA021 (No.1) and BA017(No.2).

i) Close the eductor discharge valves BA019(No.1) BA023 (No.2).

j) Close the eductor overboard discharge valve BA030.



Issue: 1 6.5 Loaded Voyage with Normal Boil-Off Gas Burning Page 1 of 2

Illustration 6.5a Gas Burning on Loaded Voyage

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CL702

CL400

Key

LNG Vapour

CG875

CG913

CG901

CG906

CG903

CG914

CG873

CG772

CG771

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


6.5 Loaded Voyage with Normal Boil-Off Gas Burning

Introduction

During a sea passage when the cargo tanks contain LNG, the boil-off from thetanks is burned in the ship’s boilers. The operation is started on deck andcontrolled by the ship’s engineers in the ESCR. If for any reason the boil-offcannot be used for gas burning, or if the volume is too great for the boilers tohandle, any excess vapour is vented to atmosphere (Section 4.13) via the mainmast riser.

Operation

The cargo tank boil-off gas enters the vapour header via the cargo tank gasdomes. It is then directed to one of the LD compressors which pumps the gasto the boil-off gas heater. The heated gas is delivered to the boilers at amaximum temperature of +25°C via control valve CG875. The compressor’sspeed and inlet guide vane position is governed by cargo tanks pressure. Thesystem is designed to burn all boil-off gas normally produced by a full cargoand to maintain the cargo tank pressure (i.e. temperatures) at a predeterminedlevel.

If the propulsion plant steam consumption is not sufficient to burn the requiredamount of boil-off, the tank pressure will increase and eventually the steamdump will open, dumping steam directly to the main condenser. The maindump is designed to dump sufficient steam to allow the boiler to use all theboil-off produced even when the ship is stopped.

The flow of gas through the LD compressors is controlled by adjusting thecompressor’s speed and inlet guide vane position. This is directed by the boilercombustion control when gas burning is initiated. The normal boil-off in theboiler combustion control has to be selected as well as the maximum andminimum allowed tank pressures and the tank pressure at which the maindump operates.

For normal operation, the normal boil-off valve is selected at 60% (boil-offprovides 60% of the fuel required to produce 90% of the boiler full steamcapacity) and the minimum and maximum tank pressures are selected at 105and 109kPa absolute.

If the normal boil-off valve has been correctly adjusted, the tank pressures willremain within the selected values. Should the selected normal boil-off value betoo large, the tank pressure will slowly be reduced until it reaches the minimumvalue selected. If the tank pressure value reduces to below the minimum valueselected, the normal boil-off value will be reduced until the tank pressure hasincreased again above the selected value.

If the selected normal boil-off value is too small, the tank pressure will slowlyincrease until it reaches the maximum value selected. If the tank pressure valueincreases above the maximum selected value, the normal boil-off value will be

increased until the tank pressure reduces again below the selected value.

If the tank pressure continues to increase because the steam consumption is notsufficient to burn all the required boil-off, the steam dump will open.

The steam dump is designed to open when the normal boil-off valve is 5%above the original selected value and when the tank pressure has reached thepre-selected dump operating pressure.

With the present setting, an increase of 5% of the normal boil-off correspondsapproximately to an increase of tank pressure by 4kPa above the maximumtank pressure selected.

The cargo and gas burning piping system is arranged so that excess boil-off canbe vented should there be any inadvertent stopping of gas burning in the ship’sboilers. The automatic control valve CG771 at the main mast riser, is set at23kPa to vent the excess vapour to atmosphere.

If the gas header pressure falls to less than 2kPa above the IBS pressure, analarm will sound.

In the event of automatic or manual shut down of the gas burning system, or ifthe tank pressure falls to 1kPa above the insulation spaces pressure, valveCG875 will close and the gas burning supply line to the engine room will bepurged with nitrogen, exhausting to No.4 vent mast via non-return valveCN429.

Operating Procedures(See Illustration 6.5a)

It is assumed that all valves are closed prior to use.

a) Prepare the LD compressors No.1 and 2, the boil-off heaters andthe engine room gas burning plant for use.

b) Open CG772 forward mast isolating valve on the gas burningheader.

c) Tank gas domes

Tank No.1 Open and lock in position valve CG170, 171




The valves should already be locked in the open position.

d) Open valve CG873 and CG901, 904, CG903, 906 vapour supplyto LD compressors and gas heaters via the mist separator.

e) Boil-off gas heater No.1:Open CG913 and 914 heater inlet and outlet.Open steam supply to heater.

In the CACC

f) Forward mast:Adjust set point control to 115kPa abs.

g) Gas compressors:Adjust the normal boil-off valve (IGV) to 60% for loadedcondition, tank pressures minimum and maximum at 106kPa abs.and 109kPa abs. and steam dump opening pressure at 113kPa abs.

When the engine room is ready to start gas burning, ensure that there issufficient nitrogen to purge the lines to the boiler i.e. >5.0 bar in the buffertank.

h) Ensure that the gas outlet temperature of the heater is approximately 25°C.Open valve CG875.Start the LD compressor(s).

This operation will then be controlled and monitored from the ESCR.

(Note ! If the volume of boil-off exceeds demand in the boilers, the steamdump should be put into operation.)

Should the system shut down for any reason, valve CG875 will close auto-matically.

i) Stop the compressor.Shut the steam off the boil-off heater.

When stopping gas burning for any reason.

j) Stop the LD compressor(s).Shut down the boil-off heater.Close valve CG875, the gas supply to the engine room.Adjust the set point of the vent mast control CG771 to 110kPaabs.

Issue: 1 6.5 Loaded Voyage with Normal Boil-Off Gas Burning Page 2 of 2


Issue: 1 6.6 Unloading Page 1 of 8

Illustration 6.6.1a Inerting Manifold Connections

CL041

CS057 CS067

CS767

CS055 CS065

CS765

CG079

CS053 CL063

CS763

CS051 CS061 CS062 CS052

CS054 CS054

CS056 CS056

CS058 CS058

CS761

CS768

CS766

CS764

CS762

CS750

CargoVapour

CargoLiquid

Forward

SprayMain

CL043 CL044 CL042

CL034 CL032

CL024 CL022

CL014 CL012

CL031 CL033

CL023

CG077

CG071

CG078

CG072

CL011

CL085

CL086

CL081

CL082

CG080

CG081

CL089

CL090

CL093

CL094

CL087

CL088

CL083

CL084

CG082

CG083

CL091

CL092

CL095

CL096

CL013

Key

LNG Liquid

LNG Vapour

Nitrogen

CL021

F


6.6 Unloading Discharging with Gas Return from Shore

Introduction

During a normal discharge, only the main cargo pumps will be used and aquantity of cargo will be retained on board for cold maintenance of the cargotanks.

The quantity to be retained is according to the voyage duration of the ballastpassage.

If the ship has to warm up tanks for technical reasons, the stripping/spraypumps will be used to discharge the remaining cargo on completion of bulkdischarge with the main cargo pumps.

During cargo discharge, LNG vapour is supplied from shore to maintainpressure in the cargo tanks.

Operation

The main cargo pumps discharge LNG to the main liquid header and then toshore via the midship liquid crossover manifold connections.

After an initial rise in pressure, the pressure in the tanks decreases. It thenbecomes necessary to supply LNG vapour from shore via the manifold andcrossover to the vapour header into the cargo tank gas domes in order tomaintain a pressure of 109kPa absolute.

Should the vapour return supply from shore be insufficient to maintain tankpressures, other means of supplying vapour to the tanks either by using thetank sprayers or the main vaporizer, have to be used.

The boil-off gas heater should be prepared and lined up for use in order toavoid venting cold LNG vapour through the main mast riser.

Ballasting is undertaken at the same time as discharging. The ballastingoperation is programmed to keep the vessel within the required limit ofdraught, trim, hull stress and stability following indications obtained from theloading calculator.

During the discharge period, the ship is kept on an even keel. If it is requiredto empty a cargo tank, the ship is trimmed according to terminal maximumdraught by the stern to assist in stripping of the tank.

Each tank is normally discharged down to a level of about 0.2m in tanks otherthan the heel tank. The level in the heel tank will depend upon the length of theballast passage, and will be adjusted accordingly. The quantity being retainedin tanks varies according to the length of ballast voyage, expected elapsed timebefore loading and the volume of boil-off that is estimated to be burned in the

ship’s boilers.

One pump is stopped at a level of approximately 0.6m to avoid excessiveturbulence at the tank bottom which creates disturbance at the suction of bothpumps.

If the vessel is to warm up one or more tanks for technical reasons, the shipshall be trimmed according to terminal maximum draught. The cargoremaining in the tanks to be warmed up will be discharged to shore or to othertanks using the stripping/spray pumps on completion of bulk discharge.

The stripping pump is run together with the remaining main pump until themain pump stops on low discharge pressure cut-out.

On completion of discharge, the loading arms and pipelines are purged anddrained to No. 4 cargo tank and the arms are then gas freed and disconnected.

Due to the manifold configuration it is necessary to purge the cargo lines usingnitrogen at a pressure of at least 300kPa; this being done several times toensure successful draining at the manifold connections.

The vapour arm remains connected until just before sailing, if a delay isexpected.

6.6.1 Preparation for Unloading(See Illustration 6.6.1a)

It is assumed that all valves are closed prior to start.

Preliminary preparation:

a) Checks to be made prior to starting cargo operations. Test remote operation of all tank discharge valves and manifoldESD valves.Test remote operation of ballast valves.Test the operation of the Emergency Shut Down Systems (ESDS).

b) Safety precautions:Ensure the sprays for the hull water curtain at midships are inoperation.Prepare all fire fighting equipment, water hoses and protectiveclothing for use.

c) Cargo tanks level arms:Switch on the high level alarms.

d) Tank vapour domes - confirm that:

Open and lock in position valves CG170, 171 Tank No.1




These valves must be locked open at all times when the ship hascargo on board, unless a tank is isolated and vented for anyreason.

e) Vapour crossover: Open valve CG079.

f) Cargo pumps:Check that there is sufficient power for the cargo pumps to be run.

g) Check connections of liquid and vapour arms.Check communications with shore.Check ship/shore link.

When shore is ready to purge manifold connections with nitrogen:

h) Liquid manifold connections (assuming port-side discharge)Open drain valves CL093, 094, 089, 090, 085, 086, 081, and 082.Purge the connections then close the valves.

i) Vapour manifold connectionOpen drain valves CG080, 081.Purge the connection then close the valves.

If shore agree:

j) Vapour manifold:Open manifold ESD valve CG071.

k) Liquid connections:Open manifold ESD valves CL011, 021, 031, and 041.

l) Test ESDS from shore and from ship as required. Re-open theliquid and vapour ESD valves.

When it is agreed with shore that cooldown may commence:




Illustration 6.6.2a Liquid Line Cooldown Before Unloading

H

H

H

H

H

CL410

Key

LNG Liquid

LNG Vapour

CL013CL023

CL033CL043

CL110

CS156

CS154

CL044CL034

CL024 CL014

CS751

CS250

CS350

CS351

CS354

CS355

CS255

CS256

CS356

CS067

CS065

CS063

CS061

CS761

CS763

CS765

CS068

CS066

CS064

CS062

CS456

CS454

CL041CL031

CL021CL011

CL042

CL022

CL032

CL012

CS750

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CL310

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid Dome


6.6.2 Liquid Line and Arm Cooldown Before Unloading(see illustration 6.6.2a)

In-service operations have shown the following procedure for liquid line andhard-arm cooldown has proven the most effective and efficient way to becarried out.

To cool down the cargo and discharge lines, proceed as follows assuming thatstripping/spray pump No.2 and No.3, manifold lines No.1, 2 and 3 are beingused and that the ESD valves are open, having been purged with nitrogen.

a) Open discharge valve CS250 from No.2 stripping/spray pump to30%.

b) Open the following valves CS255, 256, CL256, CL110, CL410,CS156, 154, 456, 454, CS761, 061, 763, 063, 765, 065.

c) Start No.2 stripping/spray pump.Begin to cooldown the hard-arms and shore side lines. Vapourgenerated will be relieved into No.1 and 4 tanks.

d) Line up No.3 stripping/spray pump, open valves CS355, 356,CL310 and the pump discharge valve 30%. When valves are set,start the pump.

d) When the manifold lines have cooled down to -100°C, openvalves CL011, 021, 031. This will now cool down the shore liquidline and hard-arms. As liquid is observed flowing into the hard-arms, stop No.3 stripping/spray pump. This is in order to reducethe liquid flow and hence the cooldown rate of the hard-arm ballvalves.

The cooling down is complete when the manifold, ship’s liquid line and shorelines are approximately -130°C. This will take approximately 80 minutes.

e) Stop the stripping/spray pumps.Shut valves CS256, 356.

f) When the stripping/spray pump line has warmed up, close valvesCS250, 255, 350, 355.

On completion of cooldown and when shore is ready for discharge, proceed asfollows for unloading.




Key

Illustration 6.6.3a Unloading With Gas Return from Shore

LNG Liquid

LNG Vapour

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL110

CL201CL202

CL101CL102

CL302CL301

CG079

CL041CL031

CG071

CL021CL011

CL013CL023

CL033CL043

CL402

CL401

CL042

CL044CL034

CL022

CG078

CL032

CL012

CL024 CL014

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid Dome


6.6.3 Unloading(see illustration 6.6.3a)

Before starting the main cargo pumps on No.2 and 3 tanks (these being the firsttanks), it is necessary to fill the discharge column with LNG to avoid pressuresurge in the lines. Starting with No.3 tank.

a) Open No.3 spray pump discharge 30%, valve CS350.

b) Open the pump columns vent valves CL307, 308.

c) Open the spray discharge to pump columns valves CS355, 356,C301, 302.

d) Start the spray pump.

e) Stop the spray pump when the liquid header at the tank top is full.

f) Shut spray line valves CS350, 355, 356.

g) Shut vent line valves CL307, 308.

Repeat the operation with No.2 tank; the vessel is now ready to start discharge.

h) Open No.3 tank liquid header valve CL310.

i) Open No.3 tank main cargo pump discharge valve CL301 or 302to between 25% (normal) and 30% (maximum).

Inform the ESCR that a main cargo pump is about to be started.

j) Start the main cargo pump.

k) Check the lines for leakage.Open the discharge valve fully on the running pump.

l) When shore is ready to receive further cargo, proceed as for h) toj) on each pump.

The preferred sequence in chronological order of cargo pump starting, toobtain a stable discharge operation is as follows:

Tank No.3, Tank No.2, Tank No.4, Tank No.1

m) Monitor the tank’s pressure.

n) Request vapour return from shore and continue to monitorpressure to confirm that it stabilises.

o) As the discharge pressure and flow rate increase, continue tomonitor the pipework and hard-arms for leakage.

p) Adjust the pump discharge valves to obtain the optimumperformance as indicated by current and discharge pressure asindicated on the pump graph.

q) It is important to maintain the tanks at a pressure of at least100kPa gauge, in order to avoid cavitation and to have goodsuction at the pumps. If the tank’s pressure falls to 60kPa gauge,request shore to increase the gas return.

If shore can no longer supply gas return, the main vaporizer will have to bestarted up to restore the tank’s pressure.

r) Start ballasting operations.Keep draught, trim and hull stresses within permissible limits bycontrolling the various ballast tank levels.Refer to the trim and stability data provided.

s) Continue to monitor the tank pressures and cargo pump currentand discharge pressures.

t) Throttle each pump discharge valve as required to preventtripping on low current as the level in each tank drops.

Stop the main cargo pumps in each tank at approximately 370mm.

Throttle in the main cargo pump discharge valve to 40% before stopping thepump. If two main cargo pumps are in use in a tank, when the level reaches0.65m, throttle in the discharge valve on one pump to 40% and stop that pump.This is in order to reduce turbulence around the pump suction.

On completion of final tank and after all cargo pumps have been stopped:

u) Drain the liquid line.

v) Stop gas return from shore.

If stripping of tanks ashore is required, via forward manifold connection, seesection 6.7.1, Stripping and Line Draining.

Purging and Draining the Loading Arms

Purging is carried out one line at a time.

When the shore terminal is ready to inject nitrogen and the pressure at themanifold is 250kPa.

a) Open manifold bypass valves CS501.

b) Close the bypass valve when pressure on manifold drops to 0 kPa.Repeat the operation twice more. On the last operation, shut thebypass valve at approximately 100kPa, in order to eliminate therisk of liquid back flow from the ship’s liquid line.

Open the test drain valve on the loading arm to ensure that there is no liquidpresent. When the required amount of methane (usually less than 1%) isshowing at the drain valve, close the shore terminal ESDS valves.

c) When purging is completed, proceed with the disconnection ofthe liquid arms.

d) Complete ballasting operations for final measurement and forsailing condition.

Shortly before departure:

e) Vapour line connection:Purge the vapour line with nitrogen from the shore terminal at apressure of 200kPa.Close valve CG071, 079.Confirm that the gas content is less than 1% by volume at drainvalve CG073, 074.

After confirming that the gas content is less than 1% volume:

f) Disconnect the vapour arm.

g) Prepare the cargo system for gas burning at sea.


H

H H

H

CL310

1

2

Liquid Dome

H

CS350

CS351

CS354

CS355

CL308

CS356

CL302CL301

CL307H

Illustration 6.6.3b






GS Pump

BA501

Fore PeakTank

BosunStore

BA502


BA032BA012

BA013

BA009

BA010

BA002

BA003

BA006

BA011

BA027

BA025

BA025

To IGGenerator

WS118

WS117


3,000m3/h



Self Priming

BA026

BA029

BA031

BA513BA517BA5021


Key

Sea Water Ballast











ForwardBallast Tank

Port

Illustration 6.6.4a Ballasting

Hydraulic Line

BA507

BA506

BA505WS172

BA001

BA008BA524

BilgeSuction

From PipeDuct

BA023

No.2 Eductor300m3/h

No.1 Eductor300m3/h

BA015

BA007

BA004



Low Suction


BA017

BA021

BA019

BA030

FD032 FD010 FD020

BA028

To/FromAft Peak

Tank


Emergency Use





BA020

BA016

PI PT PI

PI PT PI

PI

PI

LS ZI

LS ZI

LS ZI

PI

PI

PI PIPSPT

PI PIPSPT

PI PIPSPT

PI PT PI

PT

LIAH

BA12LIAH

BA10LIAH

BA08LIAH

BA06LIAH

BA09LIAH

BA11LIAH

BA07LIAH

BA05LIAH

BA04LIAH

BA03LIAH

BA02LIAH


6.6.4 Ballasting


It is assumed that the main sea water crossover pipe is already in use,supplying other sea water systems, e.g. the main circulating system, the seawater service system and that the cargo and ballast valve hydraulic system isalso in service.

To Ballast the Ship

! CautionMal-operation of the ballast system will cause damage to the GRPpipework. Damage is generally caused by pressure surge due to suddenchanges in the flow and presence of air pockets. During the ballastingoperation great care must be taken to ensure that flow rates are adjustedsmoothly and progressively. In particular, the pumping rate should bereduced to one pump when filling only one tank and use made of thedischarge to sea to further reduce the rate before shutting the final tankvalve.

It is necessary to eliminate the air pockets that may be present in the pipingbefore proceeding with the normal ballasting operations. This is achieved byrunning ballast into either the forward ballast or No.1 ballast tank.

It is important not to compress any air in the system. To achieve this, the valveadmitting water to the system should be opened last.

Fill by Gravity

All operations are carried out from the control room using the keyboard inconjunction with the mimic board Ballast.

a) Open the valves BA504 and BA503 on the forward ballast tanks.

b) Open the ballast main valves BA002, BA012, BA031 and BA032.

c) Open the gravity filling valve from sea BA003, BA013. When aflow has been established to the forward ballast tanks, the valvesBA504 and BA503 can be shut.

d) Open the valve(s) on the tank(s) to be filled as per the ballast plan.

Forward port BA504


No.1 port BA509


No.2 port BA513


No.3 port BA517


No.4 port BA521


e) As the level in each tank reaches that required, open the valve ofthe next tank before closing the valve of the full tank.

f) When all the tanks are at their correct level, shut the tank valves,ballast main valves and gravity filling valves BA032, BA031,BA012, BA013, BA002 and BA003.

(Note ! The speed when filling by gravity will sharply decrease as the level ofthe water line is approached. The tanks will require to be filled to their capacitywith the ballast pump.)

To Ballast Ship Using Port Ballast Pump

a) Open the valve(s) on the tanks to be filled as required by theballast plan:

Forward port BA504


No.1 port BA509


No.2 port BA513


No.3 port BA517


No.4 port BA521


b) Open the sea water crossover valves and bulkhead valves BA008,BA001, BA032, BA031, and BA015.

c) Open the sea water inlet valves to the port pump BA013.

d) Start the port ballast pump.

e) Open the pump discharge valve BA014.

f) As the level in each tank reaches that required, open the valve ofthe next tank before closing the valve of the tank which is full.

g) When all the tanks near the required level, reduce the flow rateprogressively by discharging to sea via the overboard dischargevalve BA026.

h) Close the final tank valve when the required level is reached.

i) Close the pump discharge valve BA014 and stop the pump.

j) Close all other valves.

To Ballast the Ship Using the Centre Ballast Pump

a) Follow operations a) to b) inclusive.

b) Open the sea water inlet valve to the pump, BA010.

c) Open valves BA025 and BA027 on the ballast dischargecrossover line.

d) Start the pump.

e) Open pump discharge valve BA011.

f) Follow operations f) to h) inclusive above.

g) Close the pump discharge valve BA011 and stop the pump.

h) Close all other valves.

To Ballast the Ship Using the Starboard Ballast Pump

a) Follow operations a) to b) inclusive.

b) Open the sea water inlet valve to the pump, BA010.

c) Open valve BA007 on the ballast discharge crossover line.

d) Start the pump.

e) Open the pump discharge valve BA006.

f) Follow operations f) to h) inclusive as per port pump operation.

g) Close the pump discharge valve BA006 and stop the pump.

h) Close all other valves.



Issue: 1 6.7 Pre Dry Dock Operations Page 1 of 8

Illustration 6.7.1a Stripping and Line Draining

H

H

H

H

H

CL410

CS455CL456

CL454

CS450

CS350

CS250

CS150

CL400

Key

LNG Liquid

CS751

CS750

CS057

CS067

CS065

CS055

CS053

CS063

CS061

CS051

CL041CL031

CG071

CL021CL011

CL013CL023

CL033CL043

CS752

CS058

CS068

CS056

CS066CS054

CS064

CS052

CS062

CL042

CL044CL034

CL022CG072

CL032

CL012

CL024 CL014

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid Dome


6.7 Pre-Dry Dock Operations

A standard letter is sent to the vessel by IMR, setting out the requirements anda timetable of operations before refit.

During the last loaded voyage before refit, a full inner hull inspection of allballast tanks and cofferdams must be carried out and a report sent to IMR. Thisis an ABS requirement, to confirm the absence or presence of any cold spots.An ABS surveyor may attend the last discharge before refit, to inspect selectedballast tanks and cofferdam spaces.

The ship will carry out a maximum discharge. The tank levels should bereduced to the point where the main cargo pumps trip on low back pressure.Then using the stripping/spray pumps remove the last of the cargo until theyalso trip on low back pressure. The ship will then proceed to sea andcommence the warm-up, inerting and aerating, prior to arrival at the refit yard.

6.7.1 Stripping and Line Draining

It is assumed that the cargo tanks have been discharged to their maximum withthe main cargo pumps which have been shut down. Discharge via the port sidemanifold.

a) At the manifold crossover:Open valve CS061.Close valves CL013, 023, 033, 043 and CL021, 031, 041.

b) Stripping/spray header:Open CS751, 752. Open CS750 stripping/spray header to liquid manifold crossover.

c) At required tanks:Open the stripping/spray discharge valves from individual tanksto give the required performance, CS150, 250, 350, 450.Start the stripping/spray pump(s).

On completion:

d) Stop the final pump.Close valves CS061 and CL011.Open valves CS455 and CS454 to drain down the header line totank No.4.

e) When completed:Leave open valves CS750, 751 752 456, in order to warm up theline. When the line has warmed up close these valves.

Purging and Draining the Loading Arms

Purging is to be carried out one line at a time.

When shore terminal is ready to inject nitrogen and the pressure at themanifold is 250kPa:

a) Open the manifold bypass valves CS051.

b) Close the bypass valve when the pressure on the manifold dropsto 0kPa. Repeat the operation a further twice. On the lastoperation shut bypass valve at approximately 100kPa, in order toeliminate the risk of liquid back flow from ship’s liquid line.

Open the test drain valve on the loading arm to ensure that there is no liquidpresent. When the required amount of methane (usually less than 1%) isshowing at the drain valve, close the shore terminal ESDS valves.

c) When purging is completed, proceed with the disconnection ofthe liquid arms.

d) Complete ballasting operations for final measurement and forsailing condition.

Shortly before departure:

e) Vapour line connection:Purge the vapour line with nitrogen from the shore terminal at apressure of 200kPa.Close valves CG071, 079.Confirm that the gas content is less than 1% by volume at drainvalve CG073, 074.After confirming that the gas content is less than 1% volume:

f) Disconnect the vapour arm.

g) Prepare the cargo system for warming up the cargo tanks.




Key

Illustration 6.7.2a Tank Warm-up

LNG Vapour

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100

CL200

CL110

CL700

CG876

CG872

CG875

CG913

CG922

CG921

CG914

CG916

002

CG900

CG920CG915 CG910

CG912

CG909

CG907

CG873

CG874


6.7.2 Tank Warm-Up

Tank warm up is part of the gas freeing operations carried out prior to a drydocking or when preparing tanks for inspection purposes.

The tanks are warmed up by recirculating heated LNG vapour. The vapour isrecirculated with the two HD compressors and heated with the cargo heaters to80°C.

In the first step, hot vapour is introduced through the filling lines to the bottomof the tanks to facilitate the evaporation of any liquid remaining in the tanks.The second step, when the temperatures have a tendency to stabilise, hotvapour is introduced through the vapour piping at the top of the tanks.

Excess vapour generated during the warm-up operation is vented toatmosphere when at sea, or returned to shore if in port. (The instructions thatfollow apply to the normal situation i.e. venting to atmosphere at sea.)

The warm-up operation continues until the temperature at the coldest point ofthe IS barrier of each tank reaches +5°C.

The warm-up operation requires a period of time dependent on both theamount and the composition of liquid remaining in the tanks, and thetemperature of the tanks and insulation spaces. Generally, the warm-up willtake about 30 hours.

Initially, the tank temperatures will rise slowly as evaporation of the LNGproceeds, accompanied by high vapour generation and venting. A venting rateof approximately 8,000m3/h at 60°C can be expected. On completion ofevaporation, tank temperatures will rise rapidly and the rate on venting will fallto between 1,000 and 2,000m3/h at steadily increasing temperatures.Temperatures within the tank and insulation are indicated in the CACC.

Rolling and pitching of the vessel will assist evaporation. Temperature sensorsat the aft end of the tank give a good indication of the progress of warm-up.Slight listing of the vessel will assist in correcting uneven warm-up in any onetank.

Gas burning should continue as long as possible, normally until all the liquidhas evaporated, venting has ceased and tank pressures start to fall.

Preparation

a) Strip all possible LNG from all tanks as follows:

b) When discharging the final cargo, remove the maximum LNGwith the stripping/spray pumps.

c) If the discharge of LNG to shore is not possible, vaporize it in themain vaporizer and vent the vapour to the atmosphere through themast riser No.1.

d) If venting to the atmosphere is not permitted, the vapour must beburned in the boilers.

e) For maximum stripping, the ship should have zero list and shouldbe trimmed down at least 0.8m by the stern.

f) Run the stripping pumps until suction is lost.

g) Remove the emergency cargo pump if it has been installed in acargo tank.

Operating Procedure (see illustration 6.7.2a)

During the tank warm-up, gas burning may be used by directing some vapourfrom the heater outlet to the boilers under manual control operation.

a) Install the elbow bend and open the valve CL702 to dischargeheated vapour to the liquid header.

b) Prepare gas heaters No.1 and No.2 for use.

c) Prepare the glycoled water heaters.

d) Adjust the temperature set point at 80°C.

e) Prepare both HD compressors No.1 and No.2 for use.

f) At vent mast No.1, open the valve CG 772.

g) Adjust the set point of CG771 to 16kPa.

h) Open the valve CG873, compressor suction from the vapourheader.

i) Open the compressor inlet and outlet valves CG907, 910, 909,912.

j) Open the heater inlet and outlet valves CG920, 913, 915, 914,916, 921, 922 and 876.

k) Open the vapour valves CG470 471, 370, 371, 270, 271, 171, 170 on each tank.

l) Open the filling valves CL400, 300, 200, 100, CL410, 310, 210,110 on each tank.

m) Start both HD compressors manually and gradually increase theflow by the inlet guide vane positioner.

n) Monitor the tank pressure and adjust the compressor flow formaintaining the tank pressure to about 16 kPa.

o) Check that the pressure in the insulation spaces, which has atendency to increase, remains inside the preset limits.

p) Monitor the temperatures in each tank and adjust the opening ofthe filling valve to make the temperature progression uniform inall the tanks.

q) After twenty/twenty-four hours, the temperature progressionslows down.

r) At the end of the operation, when the coldest temperature of theinsulation barrier is at least +5°C, stop and shut down the gasburning system if used. Stop both HD compressors, shut thefilling valves on all tanks and restore the normal venting from thevapour header.




Illustration 6.7.3a Gas Freeing

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100

CL200

CL110

CL700

CG875

002

CG910

CG912

CG909

CG907

Key

Inert Gas

LNG Vapour


6.7.3 Gas Freeing

After the tanks have been warmed up, the LNG vapour is displaced with inertgas.

Inert gas from the inert gas plant is introduced at the bottom of the tanksthrough the LNG filling piping. Gas from the tanks is vented from the top ofthe tank through the vapour header to the vent mast No.1, or to shore if in port.(The instructions which follow apply to the normal situation, venting to theatmosphere at sea.)

Inerting is necessary to prevent the possibility of having an air/LNG vapourmixture in the flammable range. The operation is continued until thehydrocarbon content is reduced to less than 2.5% (50% of the LEL). Theoperation requires about 20 hours.

In addition to the cargo tanks, all pipework and fittings must be gas freed. Thisis best done with inert gas or nitrogen, while the plant is in operation for gasfreeing the tanks.

Operating Procedure(see illustration 6.7.3a)

a) Prepare the inert gas plant for use in the inert gas mode.

b) Open the vapour valves CG470, 471, 370, 371, 270, 271, 170, 171on each tank.

c) At vent mast No.1 open the valve CG772 and adjust the set pointof CG771 at 2.0kPa g.

d) Install the elbow connecting the IG line to the LNG liquid header.Open valve CL702.

e) Open the filling valves CL400, 300, 200, 100 on each tank.

f) Start the IG generator and run it until the oxygen content and dewpoint are acceptable.

g) On the dry-air/inert gas discharge line, open the isolating valveIG001, supplying inert gas to deck.

h) Monitor tank pressures and adjust the opening of the filling valvesto maintain an uniform pressure in all the tanks. Ensure that thetank pressures are always higher than the insulation spacepressures by at least 1.0kPa, but that the tank pressures do notexceed 18.0kPa above atmospheric pressure. In any case, duringgas freeing the pressure in the tanks must be kept low, tomaximise the piston effect.

i) Approximately once an hour, take samples of the discharge fromthe vapour dome at the top of each tank and test for hydrocarboncontent. Also verify that the oxygen content of the IG remainsbelow 1%, by testing at a purge valve at the filling line of one ofthe tanks being inerted.

j) Purge for 5 minutes all the unused sections of pipelines,machines, equipment and instrumentation lines.

k) When the hydrocarbon content sampled from a tank outlet fallsbelow 2.5%, isolate and shut in the tank. On completion of tankand pipeline inerting, stop the IG supply and shut down the IGplant. Reset the valve system for aerating.

l) If the tanks are to remain inerted without aerating, shut valveCG772 and raise the pressure to 10.0kPa gauge, then shut in thetanks.

! WarningIf any piping or components are to be opened, the inert gas or nitrogenmust first be flushed out with dry air. Take precautions to avoid concen-trations of inert gas or nitrogen in confined spaces which could behazardous to personnel.




Illustration 6.7.4a Aerating Cargo Tanks

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL400

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CG370

CG371

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CG270

CG271

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100

CL200

CL110

CL700

CG876

CG872

CG875

002

CG873

CG874

Key

Inert Gas

Dry Air


6.7.4 Aerating

Introduction

Prior to entry into the cargo tanks, the inert gas must be replaced with air.

With the IG/dry-air system (see section 4.10) in dry-air production mode, thecargo tanks are purged with dry air until a reading of 20% oxygen by volumeis reached.

Operation

The IG/dry-air system produces dry air with a dew point of -55°C to -65°C.

The dry-air enters the cargo tanks via the vapour header, to the individualvapour domes.

The IG/dry-air mixture is exhausted from the bottom of the tanks toatmosphere at No.1 mast riser via the tank loading pipes, the liquid header andremovable bend and valve CL700.

During aerating the pressure in the tanks must be kept low to maximise a pistoneffect.

The operation is complete when all the tanks have a 20% oxygen value and amethane content of less than 0.2% by volume (or whatever is required by therelevant authorities) and a dew point below -40°C.

Before entry, test for traces of noxious gases (carbon dioxide less than 0.5% byvolume, and carbon monoxide less than 50ppm) which may have been con-stituents of the inert gas. In addition take appropriate precautions as given inthe Tanker Safety Guide and other relevant publications.

The pressure in the tanks is adjusted to 12 kPa.

Aeration carried out at sea as a continuation of gas freeing will take approxi-mately 20 hours.

! WarningTake precautions to avoid concentrations of inert gas or nitrogen inconfined spaces, which could be hazardous to personnel. Before enteringany such areas, test for sufficient oxygen > 20% and for traces of noxiousgases: CO2 < 0.5% and CO < 50 ppm.

The operating procedure is as follows: (see illustration 6.7.4a).

a) Prepare the inert gas plant for use in the dry-air mode.

b) Install the elbow bend for venting the mixture inert gas/dry-airfrom the LNG header.

Install the elbow bend supplying dry-air to emergency vent line.At the vent mast No.1, open the valves CG772 and CL700. Adjustthe set point of CG771 at 16 kPa above atmospheric pressure.

c) Open the filling valves CL400, 300, 200, and 100 on each tank.

d) Open the vapour valves CG470 471, 370, 371, 270, 271, 170, 171 on each tank.

e) On the dry-air/inert gas discharge line, open the dry-air supplyvalve.

f) Start the IG/dry-air generator in dry-air mode.

g) Open the valves CG876, 872 to supply dry-air to the vapourheader.

h) Observe the tank pressures and insulation space pressures, toensure that the tank pressures are higher than the space pressuresby 1kPa gauge at all times.

i) Approximately once an hour, take samples from the filling pipetest connections to test the discharge from the bottom of the tanksfor oxygen content.

j) When the oxygen content reaches 20%, isolate and shut in thetank.

k) When all the tanks are completed and all piping has been airedout, raise the pressure to 10kPa gauge in each tank and shut thefilling and vapour valves on each tank. Restore the tank pressurecontrols and valves to vent from the vapour header.

l) During the time that dry-air from the inert gas plant is supplied tothe tanks, use the dry-air to flush out inert gas from vaporizers,compressors, gas heaters, crossovers, pump risers and emergencypump wells. Piping containing significant amounts of inert gasshould be flushed out. Smaller piping may be left filled with inertgas or nitrogen.



Part 7Emergency Procedures

Part 7 Emergency Procedures

Introduction

All tests carried out on the IBS membrane have shown that a fatigue fracturein the membrane will not extend.

Fatigue fractures in the IBS membrane are generally small and will pass eithervapour only, or a sufficiently small amount of liquid, which will vaporize as itpasses through the fracture.

It is possible, however, that a larger failure of the membrane could occur,allowing liquid to pass through and eventually gather at the bottom of the interbarrier space.

Leakage Detection

7.1 LNG Vapour Leakage to Barrier

Under normal operations the IBS and IS barrier spaces are continually sweptwith nitrogen. Indication of a vapour leakage will be indicated by the gassampling analyser.

Issue: 1 Part 7 Emergency Procedures Page 1 of 14



Illustration 7.2a Arrangement of IBS and IS Piping on Liquid Dome

To N2 Vent

To Gas Detector

Aft Bilge Well

Nitrogen Supply to ISVia Cofferdam Space

Nitrogen Supply to IBSBottom

Blank Flange ConnectionFor Stripping of Leaked Cargo

(Bottom Part Aft)Connection for Portable Liquid LevelGauging and Sample Point for

IS (Low point)Connection for Portable Liquid Level

Gauging and Sample Point forIBS (Low point)

Connection for PortableSample Point forIS (High point)

CofferdamForward Bilge Well

IS

IBS


7.2 LNG Liquid Leakage to Barrier

A major failure in the primary membrane, allowing liquid into the interbarrierspace, will be indicated as follows:

A rapid increase in the methane content of the affected space.

A rise in pressure in the interbarrier space nitrogen header,accompanied by continuous increased venting to atmosphere.

Low temperature alarms at all temperature sensors in theinsulation below the damaged cargo tank.

A general lowering of inner hull steel temperatures.

If a major failure of the membrane occurs, liquid from the tank will flow intothe interbarrier space until the levels in both compartments are equal. When thecontents of the cargo tank are discharged, unless the LNG in the interbarrierspace can drain sufficiently quickly to the cargo tank a differential liquid headwill build up, tending to collapse the membrane of the tank.

Interbarrier Space Drainage System

LNG in the bottom of the interbarrier space is removed through the eightnitrogen inlet tubes, at the aft end of each liquid dome. During the discharge ofaffected cargo tank the portable elbow bend is swung and connected to thespray header at the blank flange connection (MB601.62) provided on eachtank.

The LD compressor is set to draw from the spray header via the forcingvaporizer and discharge to atmosphere through the forward vent mast. Thevaporizer, which is steam heated, is used to vaporize the LNG prior to enteringthe compressor and protects the rotors from any LNG carry over.

An increase in pressure due to vapour leakage will be less obvious than anincrease due to liquid leakage. This is because the volume of vapour passingthrough a fracture is small compared to the volume of liquid, which subse-quently vaporizes, passing through the same fracture. In both cases thevolumes are likely to be small in comparison with the volume of the interbar-rier space.

System Preparation

a) Isolate the nitrogen supply to the interbarrier space of tankinvolved.

b) Ensure the spray header is shut down and drained of LNG.Connect the portable elbow bend between the nitrogen header andthe spray header.

Assuming leakage is in No.4 tank. Open valves CS457, 455, 754 and 952.

c) Open valves CS903, 919 inlet and outlet to the forcing vaporizerand prepare for use.

d) Open valves on No.1 LD compressor to vapour header CG901,903, 920 and 900 and prepare for use.

e) Set the vent mast riser control valve CG771 to 10kPa, openCG772.

f) Ensure the vapour header valves on each tank vapour dome areopen.

g) Set up liquid header to transfer liquid from No.4 to No.3 tank,valves CL401, 410, 310, 300.

h) Set up the portable liquid level measuring unit to line G (see 7.2a)to IBS low point.

Procedure

The gas lift LNG removal system is designed to discharge LNG from an inter-barrier space, so that the level in this space will reduce at approximately thesame rate as the level in a cargo tank where a singe pump is running at itsdesign rate.

! CAUTIONThe MAXIMUM allowable differential head is 1m LNG.

If the level in the interbarrier space is equal to that in the cargo tank, start theLD compressor first.

If the level in the interbarrier space is well below that in the cargo tank, thecargo pump may be started first.

The LD compressor is controlled manually to maintain a suction pressure of 5to 6 kPa

With both the cargo pump and compressor running, frequently check the levelof the liquid in the interbarrier space. Adjust the discharge rate of the pump sothat the level in the tank decreases at approximately the same rate as the levelin the intebarrier space.

The portable liquid level gauge is designed to work even with a vacuum in thespace, it is not necessary to stop the compressor before checking the level.

Continue discharging until both tank and interbarrier space are drained, thenrestore the nitrogen purge system to the affected space, shut down thecompressor and vaporizer.



Image of the Elbow Bend Connection onto the SprayHeader (For Clarity, No.3 Cargo Tank is Shown)


AR581 Drain ToOverboard

BlowingConnection

For LevelGauging

For LevelGauging

For LevelGauging

For LevelGauging

Nitrogen ToInsulation

Space


Space


Space


Space

BG526

BG585

BG531BG530BG537BG536BG539BG540

BG586

BG566

AR582

BG568

BG574

BG532

BG538BG541

CN132CN174CN274CN374CN474 CN232CN332CN432

BG573

BG567

Drain ToOverboard

BlowingConnection

Tank No.4 Tank No.3

Cofferdam No.5

Tank No.2 Tank No.1

Cofferdam No.4 Cofferdam No.3 Cofferdam No.2 Cofferdam No.1

BG546BG545

From Cofferdam DrainPort and Starboard

Pipe Duct

IBS

IS

IBS

IS

Water Drain Pipe

Nitrogen Filling toInsulation Space

and Manual Sounding

Nitrogen Filling toInsulation Space

and Manual Sounding

BG548BG549

BG547BG550

BG555BG554BG557BG558BG564BG563

BG556BG559BG565

AL403404

AL401402

AL303304

AL301302

AL203204

AL201202

AL103104

AL101102

AL203204

AL301302

Key

Compressed Air

Nitrogen

Bilge Line

Illustration 7.3a Water Drain From Insulation Space


7.3 Water Leakage to Barrier

Inner Hull failure

Ballast water leakage from the wing tanks to the insulation spaces can occurthrough fractures in the inner hull plating. If the leakage remains undetectedand water accumulates in these spaces, ice accumulation can occur and causedeformation and possible rupture of the insulation. The resultant coldconduction paths forming in the insulation will cause cold spots to form on theinner hull.

The pressure differential caused by the head of water building up in theinsulation space may be sufficient to deform or even collapse the membraneinto the cargo tank.

To reduce the risk of damage from leakage, each cargo insulation space hasbeen provided with water detection units. A bilge piping system connected totwo pneumatic pumps is used for the removal of any water.

Leakage Detection

At the bottom of each cofferdam there are two bilge wells serving the forwardand aft ends of each tank insulating space. Each of these wells is fitted withtwo water detection units, one working and one spare.

Each detector is of the conductivity cell type, which causes a change inresistance due to the presence of humidity from ingress of sea water andactivates an alarm. The tank insulation space is connected to each of the foreand aft bilge wells by means of a 150mm drain pipe. The aft bilge well servesas the inlet for the nitrogen 50mm supply pipe to the insulation space. Thissupply pipe also acts as a manual sounding pipe to the bilge well.

The forward bilge well has a manual 50mm sounding pipe which can also beconnected to a portable liquid level gauge (bubbling type) and also serves as agas sample line.

Insulation Space Water Discharge

Each bilge well is connected to a 80 mm draining pipe system with a 20m3/hpneumatic pump situated in the forward and aft cofferdams for discharging thewater to deck level and then overboard by means of a flexible hose.

If ballast water is suspected of having leaked into an insulation space.

a) Pump out the ballast water from adjacent wing tanks.

b) Ventilate the pipe duct space, which runs beneath the cargo tanksand cofferdams and carry out normal enclosed space safetyprocedures.

c) To discharge water from a bilge well it is necessary to fit a spoolpiece between the bilge well drain outlet valve and the drainingpipe inlet valve, this spool piece is not normally left in position.

d) Connect a flexible hose to the pump outlet valve, forward or aft,for drain water discharge overboard.

e) Open the bilge well outlet and draining pipe inlet valves on theselected tank insulation space.

f) Open the inlet and outlet valves on the selected pump.

g) Open the air supply to the pump, continue pumping until themaximum amount of water has been discharged.

h) Carry out an inner hull inspection to determine the cause of theleak (with particular reference to safe atmosphere in the ballasttank space).

i) After the maximum possible water has been discharged from thisinsulation space, appreciable moisture will remain in theinsulation and over the bottom area. Increasing the flow ofnitrogen through the space can assist drying out the insulation.This should be continued until the moisture level is below thatdetected by the Hanla water detection system before any cargo iscarried in the affected tank.

It is possible to drain the pipe duct space of water using the same pumps if itis necessary.




Tank Top

Blind Flange

Tank LNG Liquid Level

Cable Guide

Foot Valve

Emergency Cargo PumpTerminal Connecting Box

Emergency Cargo PumpPlacement Tube

Column Flange Gasket

Support PlateAssy

LNG Discharge PipeLifting Cable

Auxiliary Cargo Pump

Lifting Assembly

Head Plate

In-Tank Power Cable

Lifting Cable

N2 Gas

Foot Valve

Column

N2 Gas

In-Tank Power CableSupport Blockand SpreaderBar Assembly

Cable Guide

Deck Power CableNitrogen Gas Nitrogen Gas Nitrogen GasNitrogen GasNitrogen GasNitrogen GasNitrogen Gas

Illustration 7.4a Emergency Cargo Pump Fitting Sequence

Key

Nitrogen Gas

LNG Liquid


7.4 Emergency Cargo Pump Installation

The emergency cargo pump is used in the unusual event that both main cargopumps have failed in a cargo tank. The pump is lowered into the emergencycargo pump column for that tank. Cables and a connection to the local junctionbox are used to power the pump. The pump, when lowered to its final position,opens the foot valve in the column and the LNG can be pumped out.

Adjacent to each pump column is a terminal box for the cargo pumpconnection and a local start switch. The pump and delivery valve are controlledand started via IAS mimic C-3, C-4.

The pump is supplied with a set of

Seven lifting strops

Three phase cargo pump power cables

Head plate with cable terminal box, power cables and mounting framefor terminal box

Seven link plates fitted with roller guides

The pump is suspended over the column into which it is being lowered by a 2.5tonne SWL derrick. For No.3 tank, the cargo crane is used. A support flangeto take the weight of the pump is used to connect each strop.

Also fitted to the column are nitrogen purge/methanol injection point.

The pump discharges into the column and to the liquid line via a dischargeconnection and valve at the top of the column.

Operating Procedure- Installation in the Tank(See illustration 7.4a)

! CautionWhen working near the open pump column all tools and equipment usedmust be attached to lanyards to avoid anything falling in the column. Allpersonal items have to be removed from pockets and the column openingmust be temporarily covered when the blind flange is removed. Use onlybrass tools.

When all equipment, pump, cables, electrical connection box and accessoriesare in position near the tank in which the pump is to be installed, prepare thederrick to lift the pump and start the pump installation.

a) The cargo tank will inevitably contain LNG, therefore the columninto which the emergency pump is being lowered must beevacuated. This is achieved by injecting nitrogen into the column.In the case of a full cargo tank, a pressure of between 200 and300kPa is required. The nitrogen forces the liquid out through thefoot valve located at the bottom of the column.

b) On completion of the expulsion of the liquid, a check must bemade at the purge cock to ensure complete inerting has takenplace. The tank pressure must be reduced to just aboveatmospheric before removing the column top blank flange. Installa new column flange gasket, then begin to install the pump usingthe derrick.

c) Install the power cables on the pump. Ensure that power cablesare carefully laid out on deck and suitably protected to avoid anydamage. The power cable ends are marked ‘A’, ‘B’ and ‘C’ andshould coincide with the same markings on the pump to ensurecorrect phase rotation.

d) Attach a strop to the pump lifting link-plate and a link-plate to thetop eye of the strop. Attach the derrick hook and lift the pump.Suspend above the column and lower the pump into the column.

e) When the pump is lowered into the column, fit the support flangewith U-slot to the column and pass the support pin through thecentre of the link-plate. Lower the link-plate so that the weight ofthe pump is taken by the pin resting across the support plates.Remove the derrick hook. Fit the cables and roller guides to thelink-plate and tighten the nuts.

f) Fit the next strop to the top of the plate and fit the next link-platewith cables and roller guides to the to eye of that strop. Attach thethe derrick hook and lift pump a few centimetres to remove thesupport pin. Lower the pump 2.5m into the column and repeat e)until all 7 strops have been attached

g) Fit the head plate lifting rod eye to the link-plate and fit thederrick hook to the top eye. Lift the pump a few cm to remove thesupport pin. Take care not to lower the pump onto the foot valve.

h) Lower the head plate onto the column and install head plate withlifting assembly in closed position, being very careful with thegasket.

i) Install the electrical assembly and support brackets. Install thedeck power cable assembly making sure that ‘A’, ‘B’ and ‘C’markings are matched at all connecting points.

Operating Procedure - Pump Cooldown and Operation

j) Start the cooldown for the pump. The pump should be leftsuspended in the empty column for 10 to 12 hours for a correctcooldown.

k) After 10 to 12 hours, introduce nitrogen pressure in the column toopen the suction foot valve with the lifting assembly in the closedposition.

l) Decrease the nitrogen pressure slowly to let the liquid rise in thecolumn at a speed of approximately 75 to 125 mm/minute until itcovers the pump completely (approximately 2m).

m) When the liquid level is above the pump, maintain the nitrogengas pressure and lower the pump completely by adjusting thelifting assembly to the open position. Tighten the gland onto thelifting rod through the head plate.

n) Stop the nitrogen supply when the liquid is at the same level intank and column and bleed the nitrogen from the top of thecolumn. The pump will have to stay immersed for one hour in theliquid before being started.

o) Before starting the pump, open the discharge valve to ensure thatthere is no pressure built up at the top of the column when startingthe pump. If necessary, excess pressure can be bled off via thepurge cock.

p) When ready to start the pump, open the discharge valve 20% andstart the pump normally.

q) Check its operation very carefully to ensure that there is noleakage at top of column or discharge piping. Fire hoses must beunder pressure and ready in the vicinity before starting.

r) Adjust the opening of the discharge valve to have requireddischarge flow and pressure within the pump capacity.

s) If the first start is not successful refer to Section 4.3.3 for theallowable number of starts.




Key

Illustration 7.6.1a One Tank Warm-up (No.4)

LNG Vapour

LNG Warm Vapour

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

CG370

CG371

CG270

CG271

CG770

CG875

CG913

CG922

CG921

CG914

CG916

CG920CG915 CG910

CG912

CG909

CG907

CL200

CL110

CG876CG874

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


7.5 Fire and Emergency Breakaway

All terminals have their own requirements regarding when it is unsafe for avessel to remain alongside a terminal; these are normally outlined in theterminal handbook.

In case of a fire or emergency developing, either on board or ashore, thefollowing basic procedures will be followed:

a) All cargo operations will be stopped and emergency signalssounded as per the terminal’s requirements as detailed in theship/shore checklist.

b) Ship and shore emergency procedures are put into operation.

c) The EDS2 system is activated, resulting in the cargo arms dis-connecting.

d) In event of fire, the IMO water spray system on ship/shore will beactivated.

e) Fire parties would attempt to deal with the situation.

f) The vessel would prepare for departure from its berth.

g) Liaise with shore personnel to arrange for pilot and tugs andadditional support.

h) The standby tug would assist with fire fighting/movement of thevessel from its berth.

i) The vessel would either move away from the berth to a safe area,under its own power with assistance of standby tug, or withadditional tugs/pilot summoned from shore.

j) The Owners/Charterers and other interested parties would beinformed of the situation.

7.6 One Tank Operation

It may be necessary for in-tank repairs to be carried out with the vessel inservice, in which case one tank can be warmed up, inerted, aerated, entered andwork undertaken on tank internals, i.e. change a cargo pump, investigate andcure problems with tank gauging systems etc. It is not envisaged that tankbarrier repairs will be carried out with one tank only warmed up.

The warm-up, inerting, aeration can be carried out with the remaining coldtanks providing boil-off gas for burning in the boilers.

Aeration should be continued throughout the repair period to prevent ingressof humid air to the cargo tank.

Tank venting is carried out by means of the emergency vent line.

Operation

At the discharge port, the tank to be worked on is discharged to the lowestmeasurable level and after completion of custody transfer and as much aspossible drained to another tank using the spray/stripping pump. Sufficientheel for the voyage together with an extra amount for cooling down the tankafter completion of repairs is retained in one of the other tanks.

7.6.1 Warm-Up (No.4 tank)

Normal gas burning is continued during this operation using vapour from alltanks.

a) Prepare the HD compressors.

b) Fit the elbow bend between the liquid line and the boil-off/warm-up heaters.

c) Fit the flexible connection between the emergency vent line andthe vapour header on No.4 tank.

d) Fit the elbow bend between the emergency vent line and theforward mast riser.

e) Open valves CL400 and CL410 on No.4 tank liquid header.

f) Open valves CL702, CG873 and CG876, CG922.

g) Open valves CG916, 914 and 921 outlet from the heaters.

h) Open valves CG913, 915 and 920 inlet to the heaters.

i) Open valves CG910 and CG912 inlet/outlet to No.2 HDcompressor.

j) Start No.2 HD compressor.

k) Monitor the gas pressure in the tank, opening valve CG770 tovent through the forward riser if the pressure in No.4 tank goesabove the set point of control valve CG771.

l) When all the liquid has evaporated and the tank temperature isrising, continue as per section 6.7.2 until the required tempera-tures are obtained and the tank is ready for inerting.




Key

Illustration 7.6.2a One Tank Inerting (No.4)

LNG Vapour

LNG Warm Vapour

Inert Gas

Inert Gas/Warm Vapour Mixture

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

CG370

CG371

CG270

CG271

CG770

CG875

CG913

CG914

CL200

CL110

CG904

CG901

CG906

CG903

CL700

CG873

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


7.6.2 Gas Freeing One Tank


Inert gas is supplied to the tank by the IG/dry-air plant via the elbow bendsconnecting onto the liquid header and exhausting via the flexible connectionbetween the vapour header and emergency vent line.

a) Fit the elbow bend between the inert gas supply line and the liquidheader.

b) Fit the spool connection between the vapour header outlet and theemergency vent line.

c) Fit the elbow bend between the liquid line and forward mast riser.

d) Raise the set point on the forward riser vent valve CG771 to17kPa.

e) Open the inert gas supply onto the liquid header valve CL702.

f) Close valves CG471, 470 on the vapour header.

g) Start the IG plant and open valve CL700.

Monitor the IG O2 reading and once a level of less than 2% oxygen is obtainedopen valvesCL410, 400 to supply IG to No.4 tank via the liquid header andvalve CG470 to exhaust via the vapour header onto the emergency vent line.

h) Open valve CG770 on the liquid line and close valve CL700.

i) Continue inerting until the levels as per section 6.7.3 are obtained.

j) Before shutting down the inert gas plant, ensure the liquid headeris purged through to the forward mast via valve CL700, inpreparation for aerating the tank.

j) Stop IG plant and close valves CG470, CG770, CL410, CL400,CL702.

Prepare the system for one tank aeration as described on the following page.




Key

Illustration 7.6.3a One Tank Aerating (No.4)

LNG Vapour

LNG Warm Vapour

Inert Gas

Dry Air

H

H

H

H

H

CG170

CG171

CG470

CG471

CL410

CG772

CG771

CL702

CL400

CG370

CG371

CG270

CG271

CG770

CG875

CG913

CG914

CL200

CL110

CG904

CG901

CG906

CG903

CL700

1

2

1



LNGVaporizer

Demister

ForcingVaporizer




Tank 1

Tank 4

Tank 2

Tank 3

VapourDome

F

F

F

F

F

H

H H

H

H

CL310

CL300

1

2

VapourDome

Liquid Dome

Liquid Dome

No.2

No.1




FCV

FCV

TCV

TCV

H

H H

H

HH

H

H

CL210

1

2

VapourDome

Liquid Dome

H

H H

H

HH

2

VapourDome

Liquid DomeCL100


7.6.3 Prepare Tank for Aeration


Dry air is supplied to the tank via the emergency vent line and vapour headerand exhausted to the forward riser via the liquid header.

a) Install the elbow bend on the IG line to the emergency vent line.

b) Ensure that valve CG471 is securely closed.

c) Open valves CL400 and CL410.

d) Open valves CG470 and CG700.

e) Start the dry-air plant.

Monitor the change in the atmosphere until all levels as described in section6.7.4, are obtained.

Ensure the pressure in the aerated tank is higher than the tanks containingvapour in order to avoid leakage of toxic gas to this tank.

Aeration is to be maintained at all times throughout the repair work.



7.7 Ship to Ship Transfer

This section is intended to complement the ICS Tanker Safety Guide,(Liquefied Gases) and the ICS Ship to Ship Transfer Guide, (Liquefied Gases)and should be supplemented by the Company’s own instructions and orders.

7.7.1 General Safety

The Master, or other person in overall control of the operation, should beclearly established before the operation commences and the actual transfershould be carried out in accordance with the wishes of the receiving ship.

The means of communication should also be well established before transferand both ships must be in direct contact with each other during the wholeoperation. Radio telephone contact should be established on VHF Channel 16and thereafter on a mutually agreed working channel. Approach, mooring,transfer and unmooring should not be attempted until fully effective commu-nications are established.

Should there be a breakdown in communications for whatever reason, either onapproach, or during transfer, the operation should immediately be suspended.

! CautionThe ignition of gas vapours may be possible by direct or induced radiofrequency energy and no radio transmissions, other than at very highfrequency, should take place during transfer operations. Arrangementsshould be made with an appropriate coast station for blind transmissionswhich would allow reception of urgent messages.

7.7.2 Pre-Mooring Preparations

Prior to mooring, the organisers of the transfer should notify the localauthorities of their intentions and obtain any necessary permits.

The two vessels should liaise with each other and exchange details of the ships,which side is to be used for mooring, the number of fairleads and bitts and theirdistance from the bow and stern of the ship to be used for mooring.

Information should also be exchanged on:

The size and class of manifold flanges to be used

The anticipated maximum height differential of the manifolds for determininghose length required

The type of hoses required and their supports to ensure that their allowablebending radius is not exceeded

The weather conditions should be taken into consideration, as that willdetermine the type and number of fenders to be used and the type of mooringprocedure to be used. Both Masters should be in agreement that conditions aresuitable for berthing and cargo transfer before the operation takes place.

All equipment to be used should be thoroughly prepared and tested, and allsafety equipment should be checked and be ready for use if required.

Cargo Equipment to be Tested

Ventilation of compressor, pump and control room to be fully operational

Gas detection systems to be correctly set, tested and operating.

Emergency shut down system to be tested and ready for use.

Pressure and temperature control units to be operational.

Cargo tanks to be cooled, if necessary.

Manifolds to be securely blanked.

Cargo hose reducers to be ready in place.

Hose purging equipment to be acceptable.

Safety Precautions

Fire main tested and kept under pressure.

Water spray system tested and ready.

Two additional fire hoses connected near the manifold and ready for use.

Dry powder system ready.

All access doors to the accommodation to be kept closed at all times duringtransfer.

No smoking.

Impressed current cathodic protection system, if fitted, to be switched off atleast three hours before transfer.

First aid equipment etc. to be ready for use.

Fenders should be positioned according to an agreed plan, taking into consid-eration the type and size of both ships, the weather conditions and the type ofmooring that is to take place.

7.7.3 Mooring

The most successful method of berthing is with both ships underway. One ship,preferably the larger, maintains steerage way on a constant heading asrequested by the manoeuvring ship, usually with the wind and sea dead ahead.The manoeuvring ship then comes alongside.

Successful operations have taken place with one ship at anchor in fine weatherconditions, and this is not too difficult if there is an appreciable current and asteady wind from the same direction. If not, then tug assistance may benecessary.

Mooring should be rapid and efficient and can be achieved by good planningby the Masters of both ships.

In general, the following points should be noted.

The wind and sea should be ahead or nearly ahead.

The angle of approach should not be excessive.

The two ships should make parallel contact at the same speed with no asternmovement being necessary.

The manoeuvring ship should position her manifold in line with that of theconstant heading ship and match the speed as nearly as possible.

Contact is then made by the manoeuvring ship, reducing the distance betweenthe two ships by rudder movements, until contact is made by the primaryfenders.

(Note ! Masters should be prepared to abort if necessary. The InternationalRegulations for Preventing Collisions at Sea must be complied with.)

On completion of mooring, the constant heading ship will proceed to ananchoring position previously agreed. The manoeuvring ship will have itsengines stopped and rudder amidships, or angled towards the constant headingship. The constant heading ship should use the anchor on the opposite side tothat on which the other ship is berthed.

From the time that the manoeuvring ship is all fast alongside, to the time theconstant heading ship is anchored, the constant heading ship assumes respon-sibility for the navigation of the two ships.

7.7.4 Transfer Operations

Transfer can begin when the two Masters have ensured that all the pre-transferchecks and precautions have been completed and agreed them. Both shipsshould be prepared to disconnect and un-moor at short notice should anythinggo wrong.

During transfer, ballast operations should be performed in order to keep thetrim and list of both vessels constant. Listing of either vessel should be avoidedexcept for proper tank draining. Checks should also be kept on the weather,traffic in the area, and that all safety equipment is still in a state of readiness.



Transfer can take place whilst the two vessels are at anchor. This is the mostcommon method. Transfer can also take place whilst the two vessels areunderway, though this depends on there being adequate sea room, trafficconditions and the availability of large diameter, high absorption fenders.

Underway TransferAfter completion of mooring, the constant heading ship maintains steerageway and the manoeuvring ship adjusts its engine speed and rudder angle tominimise the towing load on the moorings. The course and speed should beagreed by the two Masters and this should result in the minimum movementbetween the two ships. The Master of the constant heading ship is responsiblefor the navigation and safety of the two vessels.

Drifting TransferThis should only be attempted in ideal conditions.

Completion of Transfer

After transfer has been completed and before un-mooring, all hoses should bepurged, manifolds securely blanked and the relevant authorities informed thattransfer is complete.

7.7.5 Unmooring

This procedure will be carried out, under normal conditions, at anchor, thoughif both Masters agree, unmooring can take place underway.

Before unmooring begins, obstructions from the adjacent sides of both shipsshould be cleared and the sequence and timing of the event be agreed by bothships, and commenced at the request of the manoeuvring ship. Lines should besingled up fore and aft, then let go the remaining forward mooring allowing theships to drift away from each other, at which time the remaining after mooringsare let go and the ships drift clear of each other. Neither ship should, at thispoint, attempt to steam ahead or astern until their mid lengths are about twocables apart.

7.8 Jettisoning of Cargo

! WARNINGThe jettisoning of cargo is an emergency operation. It should only becarried out to avoid serious damage to the cargo tank and/or inner hullsteel structure.

A membrane or insulation failure in one or more cargo tanks may necessitatethe jettisoning of cargo from that particular cargo tank to the sea. This iscarried out using a single main cargo pump, discharging LNG through aportable nozzle fitted at ships manifold.

As jettisoning of LNG will create hazardous conditions:

a) All the circumstances of the failure must be carefully evaluatedbefore the decision to jettison cargo is taken.

b) All relevant fire fighting equipment must be manned, in a state ofreadiness and maintained so during the entire operation.

c) All accommodation and other openings and all vent fans must besecured.

d) The NO SMOKING rule must be rigidly enforced.

e) The water curtain on the side of jettison is to be running to protectship’s structure.

Weather conditions and the heading of the vessel relative to the wind, must beconsidered so that the jettisoned liquid and resultant vapour cloud will becarried away from the vessel. In addition, if possible, avoid blanketing thevapour with exhaust gases from the funnel.

The discharge rate must be limited to the capacity of one cargo pump only and,if necessary, reduce to allow acceptable dispersal within the limits of theprevailing weather conditions.

! WARNINGToo rapid a flow of LNG will result in R.P.T(Rapid Phase Transfer) whenthe liquid hits the sea water.



sk supreme cargo manual

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ballast system

cargo containment system

system sk supreme cargo

bilge system

cargo auxiliary

cargo machinery

cargo operations

drying cargo tanks