quantitative risk assessment...

MAHARASHTRA REGION PIPELINE SYSTEM

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QUANTITATIVE RISK

ASSESSMENT REPORT OF

BUNKERING FACILITIES AT JAWAHAR DWEEP (BUTCHER ISLAND)

Hindustan Petroleum Corporation Limited

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Quantitative Risk Assessment Report

BUNKERING FACILITY AT JAWAHAR DWEEP

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DOCUMENT REVISION SHEET

REPORT TITLE Quantitative Risk Assessment Report

PROJECT Bunkering Facilities at Jawahar Dweep

CLIENT Hindustan Petroleum Corporation Limited

HSE CONSULTANT iFluids Engineering

DOCUMENT NUMBER HPCL/QRA/2016/001

TOTAL NO. OF PAGES 93

ACKNOWLEDGEMENT

iFluids Engineering gratefully acknowledges the co-operation received from the management of

HPCL during the study. iFluids Engineering in particular would like to thank the Safety and other

Engineering team involved in this project for their support and help throughout the study.

DISCLAIMER

The advice rendered by iFluids Engineering is in the nature of guidelines based on good

engineering practices and generally accepted safety procedures and consultants do not accept any

liability for the same. The recommendations shown in the report are advisory in nature and not

binding on the parties involved viz. iFluids Engineering and HPCL.

1 03-12-16 Reissue for Review SPK VMa JS

0 03-12-16 Issued for Review SPK VMa JS

Rev Date Comments / Nature

of Changes Prepared

by Reviewed

by Authorized

by Approved By (HPCL)

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CONTENTS

EXECUTIVE SUMMARY ............................................................................................................... 5

QRA STUDY RESULTS ................................................................................................................. 5

1. INTRODUCTION .................................................................................................................. 8

1.1 OBJECTIVE ........................................................................................................................... 8

1.2 DEFINITIONS AND ABBREVIATIONS .................................................................................... 8

2. FACILITY DESCRIPTION ...................................................................................................... 11

3. METROLOGICAL CONDITIONS ............................................................................................ 13

4. QRA STUDY METHODOLOGOY ........................................................................................... 17

4.1 HAZARD IDENTIFICATION ................................................................................................. 18

4.2 QRA INPUT DATA .............................................................................................................. 20

4.3 CONSEQUENCE ANALYSIS ................................................................................................. 21

4.4 DAMAGE CRITERIA ............................................................................................................ 23

4.5 FREQUENCY ANALYSIS ...................................................................................................... 26

4.6 IGNITION PROBABILITIES .................................................................................................. 26

4.7 RISK ASSESSMENT ............................................................................................................. 27

4.8 RISK EVALUATION ............................................................................................................. 27

4.9 RISK REDUCTION MEASURES ............................................................................................ 27

5. DETAIL STUDY INPUTS ....................................................................................................... 28

6. STUDY RESULTS ................................................................................................................ 31

7. RISK PRESENTATION ......................................................................................................... 42

7.1 LOCATION SPECIFIC INDIVIDUAL RISK .............................................................................. 42

7.2 RISK RESULTS .................................................................................................................... 43

8. RISK ACCEPTANCE CRITERIA .............................................................................................. 45

9. PROPOSED RISK REDUCTION MEASURES BY HPCL.............................................................. 46

10. CONCLUSION AND RECOMMENDATIONS ........................................................................ 51

11. LIST OF REFERENCE DOCUMENTS / STANDARDS ............................................................. 54

ANNEXURE-I ............................................................................................................................... 55

CONSEQUENCE CONTOURS ....................................................................................................... 55

ANNEXURE-II .............................................................................................................................. 68

QRA ASSUMPTION REGISTER ..................................................................................................... 68

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LIST OF TABLES

TABLE 1 WIND ROSE .......................................................................................................................... 13

TABLE 2 PASQUILL’S STABILITY CLASS ............................................................................................... 15

TABLE 3 WEATHER CONDITIONS ....................................................................................................... 16

TABLE 4 DAMAGE DUE TO OVERPRESSURE ...................................................................................... 25

TABLE 5 CONSEQUENCE RESULTS .......................................................................................... 32

TABLE 6 RISK CRITERIA .............................................................................................................. 45

LIST OF FIGURES

FIGURE 1 WIND ROSE OF SITE ........................................................................................................... 14

FIGURE 2: QRA METHODOLOGY ........................................................................................................ 17

FIGURE 3 LOCATION SPECIFIC INDIVIDUAL RISK CONTOUR ............................................................. 43

FIGURE 4 SOCEITAL RISK – FN CURVE ............................................................................................... 44

FIGURE 5 ALARP ................................................................................................................................. 45

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EXECUTIVE SUMMARY

M/s. Hindustan Petroleum Corporation Limited (HPCL) intends to conduct Risk Analysis study for

their proposed Bunkering Facility at Jawahar Dweep to assess the risk associated with loss of

containment of the products to be stored. This scope was awarded to iFluids Engineering and

accordingly risk analysis and quantitative risk assessment study has been carried out to provide a

better understanding of the risk posed to the plant and surrounding population. The

consequences & Risk estimation modeling was conducted using PHAST and PHAST RISK (Version

6.7) software developed by DNV GL.

QRA STUDY RESULTS

Quantitative Risk analysis was performed for the identified nineteen potential hazardous scenarios

by using DNV PHAST AND PHAST RISK software version 6.7 to obtain risk results in the form of risk

contours/FN curve by combining consequence analysis results and frequencies analysis results.

The following figure illustrates the societal risk (F-N) curve for the terminal:

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The following figure illustrates the location specific risk contour (LSIR) for the terminal:

Risk reduction measures: -

Based on the input conditions such as process parameters, climatological condition, etc., the risk

posed by all the Loss of containment (LOC) Scenarios covered under this project, it is observed

that the individual risk per annum is found to fall in the Acceptable limit as per HSE UK risk

acceptance criteria. Furthermore it is suggested to implement Risk control measures provided

below for Risk Improvement of the Bunkering facilities

1. Ensure all the import/export lines to be adequately designed for the maximum pressure

source.

2. Ensure all the import/export lines are pressure tested to rated pressure before

commissioning or after any maintenance activity.

3. Provide ROV-TO3B/MOV-TO3B open feed back permissive for starting P-201 A/B pumps.

4. Provide MOV-07B open feed back permissive for starting P-202 A pump.

5. Provide MOV-01B open feed back permissive for starting P-102 A/B.

6. Provide MOV-04B/MOV-08B/MOV-02B/1003 open feed back permissive for starting the

pumps P-101 A/B.

7. Provide ROV-TO3B/MOV-TO3B close feed back trip for the pumps P-201 A/B.

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8. Provide discharge PT’s for the pumps with high pressure alarms to avoid blocked discharge

running conditions due to multiple loop operations and low pressure alarm on running

condition to identify any leak scenario.

9. Provide low suction pressure alarm and low low pressure trip for the pump to avoid dry

run operation.

10. Ensure low level, low low level, high level, high high level indications, alarms, trips are

configured as per P&ID.

11. Ensure SOP is developed/displayed for critical operations.

12. Ensure proper training/regural assessment fot the operation crew.

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1. INTRODUCTION

HPCL has awarded iFluids Engineering to carry out Quantitative risk assessment study for their

proposed Bunkering facilities at Jawahar Dweep Island.

This document presents the data considered, software modelling results, conclusion and

recommendations of the Quantitative Risk Assessment (QRA) Study.

1.1 OBJECTIVE

The main purpose and objective of this report is to,

Identification of Hazards and Major Loss of Containment (LOC) events.

Calculation of physical effects of accidental scenarios, which includes frequency analysis for

incident scenarios leading to hazards to people and facilities (flammable liquid petroleum,

fire, and smoke, explosion overpressure) and consequence analysis for the identified

hazards covering impact on people and potential escalation.

Damage limits identification and quantification of the risks and contour mapping on the

plant layout.

Risk contour mapping.

Evaluation of risks against risk acceptable limit

Risk reduction measures to prevent incident to control the accident

Hazard mitigation recommendations based on QRA

1.2 DEFINITIONS AND ABBREVIATIONS

Accidents are sudden unintended departures from normal operating conditions in which some

degree of harm is caused.

ALARP As low as reasonably practicable (ALARP)

Consequences are the expected effects of an event occurring. In QRA, it usually means the size of

the zone within which fatalities are expected, or the number of deaths.

Escape may refer to movement on the platform away from the area affected by an incident; or the

process of leaving the area.

Evacuation is the planned method of leaving the installation in an emergency.

Event tree analysis (ETA) is a technique to illustrate or quantify the various events that may follow

from one initiating event.

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Explosion - is a release of energy, which causes a blast wave capable of causing harm.

Failure - is when a system fails to perform its intended function.

Fire is a combustion process releasing heat and/or smoke.

Flash fire is combustion of a mixture of air and vapour in which the flame passes through the

cloud without causing an explosion.

Frequency is the number of occurrences of an event per unit time. In QRA, it is usually expressed

as the frequency per year.

Hazards are physical situations with a potential for causing harm.

Hazard identification is a qualitative review of possible accidents, in order to select failure cases.

Incidents are relatively minor accidents, i.e. unintended departures from normal operating

conditions in which little or no harm was caused.

Jet fire is the combustion of material released with high momentum in a concentrated jet or

spray.

Likelihood is the probability or frequency of an event occurring.

Over pressure is the excess of pressure in a blast wave.

Probability is the chance of an even to occurring in specific circumstances.

Scenarios are complete sets of circumstances necessary to define the consequences of particular

failure cases.

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ABBREVIATIONS

ALARP As Low as Reasonably Practicable

DNV Det Norske Veritas

FO Furnace Oil

HFHSD High Flash High Speed Diesel

HPCL Hindustan Petroleum Corporation Limited

HSD High Speed Diesel

HSE Health safety and Environment

IRPA Individual Risk Per Annum

IS Isolatable Section

JD Jawahar Dweep

LFL Lower Flammability Limit

LOC Loss of Containment

LSIR Location Specific Individual Risk

MOV Motor Operated Valve

NA Not Applicable

NR Not Reached

P&ID Piping and Instrumentation diagram

PSV Process Safety Valve

QRA Quantitative Risk Assessment

VCE Vapour Cloud Explosion

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2. FACILITY DESCRIPTION

Bunkering in Mumbai is currently being done at various jetties like Hay Bunder jetty, Mallet

Bunder jetty and old Pirpav, through tank trucks and barges. The pipeline supplies, though

preferred, are currently not feasible in most of the jetties except that at old Pirpav.

Typical Bunker supply parcel size ranges from 500 to 1500 MT. Handling of such huge quantity

supplies through existing Supply chain, i.e. Tank-trucks and Barges, involves intensive Operations /

multiple handling and thus poses Safety and Environmental concerns.

View above, Mumbai Port Trust (MbPT) mooted up a proposal to commission a single point for

Bunkering in Mumbai Port at MOT – Jawahar Dweep (Butcher Island) and decommission all

existing bunkering operation points (viz. Mallet Bunder, Old Pir-pau, Haybunder).

The proposal envisages facilitating barge berthing at jetty JD-2, and creation of facilities for

Bunkering at Butcher Island for seamless Bunkering operations through Pipe-line. Facilities will

include Storage tanks, input and discharge lines, pump-house etc. Details are as under:

TANKS: MbPT already has tanks in Butcher Island which are currently not in use and

have been offered to HPCL. All the tanks shall be cleaned, refurbished and put it to

use for storing of Class C bunker Fuels. Tanks proposed to be taken-over for

bunkering operations are 6 nos. with total proposed capacity of 36,600 KL.

The proposed Bunkering Terminal area is clearly earmarked for exclusive use by

HPCL and the dyke area of the Tanks, Pump House and Roads etc. is approx. 17225

sqmtr., which will be taken on lease from MbPT for a period of 30 years. Entire land

on Jawahar Dweep (Butcher Island) belongs to MbPT.

JETTY: MbPT shall be providing HPCL permission to load Barges at modified Jetty, so

that bunker product shall be directly loaded in the Barge through dedicated pipe-

lines and through Flow-meters.

HPCL proposes to develop Bunkering Terminal by Refurbishing tanks, Pipe-line modifications,

develop Tank-farm area with proper PCC, Re-construct Dyke Wall, and Refurbish other allied

facilities including fire-fighting etc.

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Accordingly, they have already signed Agreement with Mumbai Port Trust (MbPT) for taking-over

of 6 nos. of Storage Tanks, Pump House and allied facilities for setting-up of Bunker Fuel Terminal.

As per Agreement, MbPT has also offered plot portion of the said Tank-Farm premises on long

term lease (30 years) to HPCL.

HPCL proposes Storage of Petroleum Products in 6 nos. Tanks as under:

HPCL have developed layout for Development of Bunkering Terminal, drawing enclosed herewith,

so as to achieve the purpose of “Receipt of products (FO-380, HF HSD) through MbPT pipeline,

storage in 6 Nos. tanks and delivery of products (FO-380, HF HSD) for bunkering at JD-2”.

Products (i.e. FO-380 and HFHSD) shall be received through Mumbai Port Trust’s Black oil and

White Oil pipe-lines respectively, from the HPCL Mahul Refinery. Product may also be received

through Pipe-line from Vessels berthing at Jawahar Dweep/ Pirpau.

Normal pipe-line contents in these MBPT’s pipe-line are FO-180 and HSD respectively.

Accordingly, it is envisaged to designate one tank each for storage of pipe-line content of FO-180

and HSD. Post receipt operations, this pipe-line content will be pushed-back to the pipe-line.

Delivery of the products (FO-380 and HFHSD) shall be primarily through MbPT Bunkering line in

the barges berthed at JD-2.

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3. METROLOGICAL CONDITIONS

This chapter describes the meteorological data which have been used for the risk assessment

study of the Bunkering facility.

The consequences of released flammable material are largely dependent on the prevailing

weather conditions. For the assessment of major scenarios involving release of flammable

materials, the most important meteorological parameters are those that affect the atmospheric

dispersion of the escaping material. The crucial variables are wind speed, wind direction,

atmospheric stability and temperature. Rainfall does not have any bearing on the results of the

risk analysis; however, it can have beneficial effects by absorption/washout of released materials.

Actual behavior of any release would largely depend on prevailing weather condition at the time

of release.

Wind Speed and Wind Direction

Based on the meteorological data provided in the table 1, the predominant wind speed of 2 and 5

m/s is considered for the risk analysis of terminal. Meteorological data of site have been taken

from the climatological observations from meteoblue website.

Table 1 Wind Rose

wind speed m/s

0 >0.3 >1.6 >3.4 >5.5 >8 >10.8 >13.9 >17.2

Total in terms of

wind direction

N 0.001484 0.027169 0.009361 0.000685 0 0 0 0 0 0.0387

NNE 0.001256 0.022032 0.007763 0.000571 0 0 0 0 0 0.0316

NE 0.000457 0.02226 0.010845 0.002055 0.000114 0 0 0 0 0.0357

ENE 0.001256 0.039498 0.076256 0.00879 0.000799 0 0 0 0 0.1266

E 0 0.014612 0.031393 0.005365 0.000913 0 0 0 0 0.0523

ESE 0.000799 0.008676 0.002968 0.000685 0.000114 0 0 0 0 0.0132

SE 0.000342 0.005137 0.001484 0.000342 0 0 0 0 0 0.0073

SSE 0 0.005137 0.001712 0.000457 0 0 0 0 0 0.0073

S 0.002511 0.014726 0.010502 0.003881 0.000799 0.000114 0 0 0 0.0325

SSW 0.000228 0.015868 0.03984 0.015525 0.003082 0.000342 0 0 0 0.0749

SW 0.000913 0.031393 0.077055 0.039041 0.011073 0.000571 0 0 0 0.1600

WSW 0 0.028082 0.050571 0.02089 0.010731 0.000457 0 0 0 0.1107

W 0.001256 0.039954 0.056735 0.028995 0.019863 0.000114 0 0 0 0.1469

WNW 0.000342 0.023744 0.035274 0.018836 0.008447 0.000114 0 0 0 0.0868

NW 0.001256 0.025228 0.017352 0.00411 0.000685 0 0 0 0 0.0486

NNW 0 0.017466 0.009018 0.001027 0 0 0 0 0 0.0275

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Figure 1 Wind Rose of Site

Ambient Conditions

Ambient Temperature : 30°C

Average Relative Humidity : 75 %

Weather category

One of the most important characteristics of atmosphere is its stability. Stability of atmosphere is

its tendency to resist vertical motion or to suppress existing turbulence. This tendency directly

influences the ability of atmosphere to disperse pollutants emitted into it from the facilities. In

most dispersion scenarios, the relevant atmospheric layer is that nearest to the ground, varying in

thickness from a few thousand meters. Turbulence induced by buoyancy forces in the atmosphere

is closely related to the vertical temperature gradient.

Temperature normally decreases with the increasing height in the atmosphere. The rate at which

the temperature of air decreases with height is called Environmental Lapse Rate (ELR). It will vary

from time to time and from place to place. The atmosphere is said to be stable, neutral or

unstable according to ELR is less than, equal to or greater than Dry Adiabatic Lapse Rate (DALR),

which is a constant value of 0.98°C/100 meters.

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Atmospheric Stability

Pasquill stability parameter, based on Pasquill – Gifford categorization, is such a meteorological

parameter, which decreases the stability of atmosphere, e.g., the degree of convective

turbulence.

Pasquill has defined six stability classes ranging from ‘A’ (extremely unstable) to ‘F’ (very stable).

Wind speeds, intensity of solar radiation (daytime insulation) at night time sky cover have beam

identified as prime factors defining these stability categories. Below table indicates the various

Pasquill stability classes.

Table 2 Pasquill’s Stability Class

Wind Speed

(m/s)

Day: Solar Radiation Night: cloud Cover

Strong Moderate Slight Thinly <

40% Moderate

Overcast >

80%

<2 A A-B B - - D

2-3 A-B B C E F D

3-5 B B-C C D E D

5-6 C C-D D D D D

>6 C D D D D D

A – Very Unstable

B – Unstable

C – Slightly Unstable

D – Neutral

E – Stable

F – Very Stable

When the atmosphere is unstable and wind speeds are moderate or high or gusty, rapid

dispersion of pollutants will occur. Under these conditions, pollutant concentrations in air will be

moderate or low and the material will be dispersed rapidly. When the atmosphere is stable and

wind speed is low, dispersion of material will be limited and pollutant concentration in air will be

high. In general, worst dispersion conditions (i.e. contributing to greater hazard distances) occur

during low wind speed and very stable weather conditions, such as that at 1F weather condition

(i.e. 1 m/s wind speed and Pasquill stability F).

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Stability category for the present study is identified based on the cloud amount and wind speed.

For risk analysis the representative average annual weather conditions are assesses based on the

following:

Based on the weather analysis, predominant weather stability of “F” and “D” was selected with

wind speed 2 m/s and 5 m/s for consequence analysis, respectively. The consequence results are

represented in tabular form for all the weather conditions and are represented graphically for

worst weather condition.

Table 3 Weather conditions

Wind Speed in m/s Pasquill Stability

2 F

5 D

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4. QRA STUDY METHODOLOGOY

This section presents a brief description of the approach and steps followed in the QRA study.

The QRA Study included the following steps:

Identification of the hazardous events associated with the project facility;

Consequence modelling of the physical effects;

Estimation of total failure frequencies;

Evaluation / assessment of the risks arising from the pipeline network with respect to

UK HSE Risk Acceptance Criteria;

Recommending risk reduction measures.

The overall QRA methodology is shown in Figure 2 and is described in more detail in the

subsequent sections.

Figure 2: QRA Methodology

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4.1 HAZARD IDENTIFICATION

The hazardous scenarios considered in the QRA for the project facility will be identified based on

the properties of the materials handled and the identification of the potential hazards in the

pipeline systems which could lead to loss of containment events.

A technique commonly used to generate an incident list is to consider potential leaks and major

releases from fractures of all process pipelines and vessels. This compilation includes all pipe work

and vessels in direct communication, as these may share a significant inventory that cannot be

isolated in an emergency. The following data were collected to envisage scenarios:

Composition of materials stored in vessels / flowing through pipeline

Inventory of materials stored in vessels

Flow rate of materials passing through pipelines

Vessels / Pipeline conditions (phase, temperature, pressure)

Connecting piping and piping dimensions.

Accidental release of flammable liquids / gases can result in severe consequences. Delayed

ignition of flammable gases can result in blast overpressures covering large areas. This may lead to

extensive loss of life and property. In contrast, fires have localized consequences. Fires can be put

out or contained in most cases; there are few mitigating actions one can take once a flammable

gas or a vapour cloud gets released. Major accident hazards arise, therefore, consequent upon the

release of flammable gases.

FACTORS FOR IDENTIFICATION OF HAZARDS

In any installation, main hazard arises due to loss of containment during handling of flammable

liquids / gases. To formulate a structured approach to identification of hazards, an understanding

of contributory factors is essential.

Blast over Pressures

Blast Overpressures depend upon the reactivity class of material and the amount of gas between

two explosive limits. For example, MS once released and not ignited immediately is expected to

give rise to a gas cloud. These gases in general have medium reactivity and in case of confinement

of the gas cloud, on delayed ignition may result in an explosion and overpressures.

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Operating Parameters

Potential gas release for the same material depends significantly on the operating conditions. The

gases are likely to operate at atmospheric temperature (and hence high pressures). This operating

range is enough to release a large amount of gas in case of a leak / rupture, therefore the pipeline

leaks and ruptures need to be considered in the risk analysis calculations.

Inventory

Inventory Analysis is commonly used in understanding the relative hazards and short listing of

release scenarios. Inventory plays an important role in regard to the potential hazard. Larger the

inventory of a vessel or a system, larger is the quantity of potential release. A practice commonly

used to generate an incident list is to consider potential leaks and major releases from fractures of

pipelines and vessels/tanks containing sizable inventories.

Range of Incidents

Both the complexity of study and the number of incident outcome cases are affected by the range

of initiating events and incidents covered. This not only reflects the inclusion of accidents and / or

non-accident-initiated events, but also the size of those events. For instance, studies may evaluate

one or more of the following:

catastrophic failure of container

large hole (large continuous release)

smaller holes (continuous release)

leaks at fittings or valves (small continuous release)

In general, quantitative studies do not include very small continuous releases or short duration

small releases if past experience or preliminary consequence modeling shows that such releases

do not contribute to the overall risk levels.

SELECTION OF INITIATING EVENTS AND INCIDENTS

The selection of initiating events and incidents should take into account the goals or objectives of

the study and the data requirements. The data requirements increase significantly when non -

accident - initiated events are included and when the number of release size increase. While the

potential range of release sizes is tremendous, groupings are both appropriate and necessitated

by data restrictions. The main reasons for including release sizes other than the catastrophic are

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to reduce the conservatism in an analysis and to better understand the relative contributions to

risk of small versus large releases.

As per CPR 18 E guidelines & Reference Manual BEVI Risk Assessments Version 3.2 only the Loss of

Containment (LOC) which is basically the release scenarios contributing to the individual and/ or

societal risk are included in the QRA. LOCs of the installation are included only if the following

conditions are fulfilled:

Frequency of occurrence is equal to or greater than 10E-08 and

Lethal damage (1% probability) occurs outside the establishment’s boundary or the

transport route.

There may be number of accidents that may occur quite frequently, but due to proper control

measures or fewer quantities of chemicals released, they are controlled effectively. A few

examples are a leak from a gasket, pump or valve, release of a chemical from a vent or relief

valve, and fire in a pump due to overheating. These accidents generally are controlled before they

escalate by using control systems and monitoring devices – used because such piping and

equipment are known to sometimes fail or malfunction, leading to problems.

On the other hand, there are less problematic areas / units that are generally ignore or not given

due attention. Such LOCs are identified by studying the facilities and Event Tree Analysis etc. and

accidents with less consequence are ignored. Some of the critical worst case scenarios identified

by the Hazard Identification study are also assessed as per the guidelines of Environment

Protection Agency.

4.2 QRA INPUT DATA

The following activities comprise the determination of input data required for conducting the QRA

study:

Review of the project documents to determine process streams.

Identification of Loss of Containment (LOC) scenarios based on the hazardous

properties of the material.

Review of the design basis to obtain the properties of the stream (e.g. pressure,

temperature, composition and density); and

Calculation of the inventory released due to LOC events

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4.3 CONSEQUENCE ANALYSIS

Consequence assessment is conducted to understand the impact of identified scenarios in terms

of thermal radiation (Jet fire, Flash Fire, Pool Fire), Explosion (vapor cloud explosion) & toxic

dispersion. A range of potential consequences are assessed for each of the release scenarios

identified. This step identifies the fatality probability, based on hazard type and caused by each

release case, to personnel at a range of distances.

The consequence evaluation of accidental release will include the calculation of the following

parameters as a minimum:

Source term (Vapor and/or Liquid and/or Two phase discharge rate; release duration,

spreading and evaporation)

Fire characteristics (jet fire, pool fire, flash fires);

Dispersion characteristics (flammable clouds);

Explosion characteristics;

Hazardous distances (referred to radiation from fires, UFL, LFL and overpressure levels);

CONSEQUENCE ANALYSIS MODELLING

Discharge Rate

The initial rate of release through a leak depends mainly on the pressure inside the equipment,

size of the hole and phases of the release (liquid, gas or two – phase). The release rate decreases

with time as the equipment depressurizes. The reduction mainly on the inventory and the actions

taken to isolate the leak and blow-down the equipment.

Dispersion

Release of gas into the open air form clouds whose dispersion is governed by the wind, by

turbulence around the site, the density of gas and initial momentum of the release.in case of

flammable materials the sizes of these gas clouds above their lower flammability limit (LFL) are

important in determining whether the release will ignite. In the study, the results of dispersion

modeling for flammable materials are presented LFL distance.

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Consequence Events

In this section of the report we describe the probabilities associated with the sequence of

occurrences which must take place for the incident scenarios to produce hazardous effects and

the modeling of their effects.

Considering the present case, the outcomes expected are

Flash Fire (FF)

Jet fires

Pool fire

Vapour Cloud Explosion (VCE)

Flash Fire

Hydrocarbon vapour released accidentally will spread out in the direction of wind. If a source of

ignition finds an ignition source before being dispersed below lower flammability limit (LFL), a

flash fire is likely to occur and the flame will travel back to the source of leak. Any person caught

in the fire is likely to suffer fatal burn injury. Therefore, in consequence analysis, the distance of

LFL value is usually taken to indicate the area, which may be affected by the flash fire.

Flash fire (LFL) events are considered to cause direct harm to the population present within the

flammability range of the cloud. Fire escalation from flash fire such that process or storage

equipment or building may be affected is considered unlikely.

Jet fires

Jet fire occurs when a pressurized release (of a flammable fluid) is ignited by any source. They

tend to be localized in effect and are mainly of concern in establishing the potential for domino

effects and employee safety zones rather than for community risks.

The jet fire model is based on the radiant fraction of total combustion energy, which is assumed

to arise from a point slowly along the jet flame path. The jet dispersion model gives the jet flame

length.

Pool fires

A pool fire is a turbulent diffusion fire burning above a horizontal pool of vaporizing hydrocarbon

fuel where the fuel has zero or low initial momentum. Fires in the open will be well ventilated

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(fuel controlled), but fires within enclosures may become under-ventilated (ventilation-

controlled). Pool fires may be static (e.g. where the pool is contained) or 'running' fires.

Vapour Cloud Explosion (VCE)

Vapour cloud explosion is the result of flammable materials in the atmosphere, a subsequent

dispersion phase, and after some delay an ignition of the vapour cloud. Turbulence is the

governing factor in blast generation, which could intensify combustion to the level that will result

in an explosion. Obstacles in the path of vapour cloud or when the cloud finds a confined area, as

under the bullets, often create turbulence. Insignificant level of confinement will result in a flash

fire. The VCE will result in overpressures.

It may be noted that VCEs have been responsible for very serious accidents involving severe

property damage and loss of lives

4.4 DAMAGE CRITERIA

The damage criteria give the relation between the extents of the physical effects (exposure) and

the effect of consequences. For assessing the effects on human being’s consequences are

expressed in terms of injuries and the effects on equipment / property in terms of monetary loss.

The effect of consequences for release of toxic substances or fire can be categorized as

Damage caused by heat radiation on material and people;

Damage caused by explosion on structure and people;

Damage caused by toxic exposure.

In Consequence Analysis studies, in principle three types of exposure to hazardous effects are

distinguished:

1. Heat radiation due to fires. In this study, the concern is that of Jet fires and flash fires.

2. Explosions

3. Toxic effects, from toxic materials or toxic combustion products.

The knowledge about these relations depends strongly on the nature of the exposure. Following

are the criteria selected for damage estimation:

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Heat Radiation:

The effect of fire on a human being is in the form of burns. There are three categories of burn

such as first degree, second degree and third degree burns. The consequences caused by

exposure to heat radiation are a function of:

The radiation energy onto the human body [kW/m2];

The exposure duration [sec];

The protection of the skin tissue (clothed or naked body).

The limits for 1% of the exposed people to be killed due to heat radiation, and for second-degree

burns are given in the table below:

Table 4 Effects Due To Incident Radiation Intensity

Incident

Radiation (kW/m2) Type of Damage

4.0 Sufficient to cause pain within 20 sec. Blistering of skin

(first degree burns are likely)

12.5 Minimum energy required for piloted ignition of wood, melting

plastic tubing’s etc.

37.5 Sufficient to cause damage to process equipment

The actual results would be less severe due to the various assumptions made in the models arising

out of the flame geometry, emissivity, angle of incidence, view factor and others. The radiative

output of the flame would be dependent upon the fire size, extent of mixing with air and the

flame temperature. Some fraction of the radiation is absorbed by carbon dioxide and water

vapour in the intervening atmosphere. Finally, the incident flux at an observer location would

depend upon the radiation view factor, which is a function of the distance from the flame surface,

the observer’s orientation and the flame geometry.

Assumptions made for the study (As per the guidelines of CPR 18E Purple Book)

The lethality of a jet fire is assumed to be 100% for the people who are caught in the

flame. Outside the flame area, the lethality depends on the heat radiation distances.

For the flash fires lethality is taken as 100% for all the people caught outdoors and for

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10% who are indoors within the flammable cloud. No fatality has been assumed

outside the flash fire area.

Overpressure:

Vapour cloud Explosion (VCE)

The assessment aims are to determine the impact of overpressure in the event that a flammable

gas cloud is ignited. The TNO multi energy model is used to model vapour cloud explosions.

A Vapour cloud Explosion (VCE) results when a flammable vapor is released, its mixture with air

will form a flammable vapour cloud. If ignited, the flame speed may accelerate to high velocities

and produce significant blast overexposure.

The assessment aim is to determine the impact of overpressure in the event that a flammable gas

cloud is ignited. The damage effects due to 0.01 bar, 0.1 bar & 0.3 bar are reported in terms of

distance from the overpressure source.

In case of vapour cloud explosion, two physical effects may occur:

A flash fire over the whole length of the explosive gas cloud;

A blast wave, with typical peak overpressures circular around ignition source.

For the blast wave, the lethality criterion is based on:

A peak overpressure of 0.1bar will cause serious damage to 10% of the housing/structures.

Falling fragments will kill one of each eight persons in the destroyed buildings

The following damage criteria may be distinguished with respect to the peak overpressures

resulting from a blast wave:

Table 4 Damage due to overpressure

Peak Overpressure Damage Type Description

0.30 bar Heavy Damage Major damage to plant equipment structure

0.10 bar Moderate Damage Repairable damage to plant equipment &

structure

0.03 bar Significant Damage Shattering of glass

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Assumptions for the study (As per the guidelines of CPR 18 E Purple Book)

Overpressure more than 0.3 bar corresponds approximately with 50% lethality.

An overpressure above 0.2 bar would result in 10% fatalities.

An overpressure less than 0.1bar would not cause any fatalities to the public.

100% lethality is assumed for all people who are present within the cloud proper

4.5 FREQUENCY ANALYSIS

Once the potential release scenarios are identified, the next stage is to estimate the failure

frequencies (likelihood for the event to occur) based on international standard databases.

The frequency analysis will be performed as follows:

Identification of the base failure frequencies applicable to the liquid petroleum pipelines

and storage tanks from the relevant international standard databases;

The total failure frequencies will be derived from the base failure frequency data along

with the consideration of modification factors if applicable.

4.6 IGNITION PROBABILITIES

For gas/ oil releases from the gas/ oil handling system, where a large percentage of rupture events

may be due to third party damage, a relatively high probability of immediate ignition is generally

used.

Delayed ignition takes other factors into account. Delayed ignition probabilities can also be

determined as a function of the cloud area or the location. In general, as the size of the cloud

increases, the probability of delayed ignition decreases. This is due to the likelihood that the cloud

has already encountered an ignition source and ignited before dispersing over a larger area (i.e.

the cloud reaches an ignition source relatively close to the point of origin).

For this study the ignition probabilities have been modified to suit the site conditions. The ignition

probabilities inside enclosed areas shall be much higher than the open areas. It is because of the

fact that there will be much more activities taking place and the possibility of ignition increases.

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4.7 RISK ASSESSMENT

Risk assessment will be undertaken to evaluate the risk associated with the project facilities. The

consequence analysis results and failure frequencies will be combined using PHAST RISK 6.7

software. The risk shall be typically presented as Location Specific Individual Risk (LSIR) contours

overlaid on a map and Individual Risk Per Annum (IRPA).

4.8 RISK EVALUATION

It involves the evaluation of the individual risk results against the UK HSE Risk Acceptance Criteria

to determine whether the risks are broadly acceptable, ALARP or unacceptable and to make some

professional judgments about the significance of the risks.

4.9 RISK REDUCTION MEASURES

Based on the risk evaluation, if the calculated risks fall in the unacceptable region, risk reduction

measures shall be implemented in order to reduce the risk to a tolerable or ALARP region. All

physically possible risk reduction measures shall be identified, which could be new measures or

improvements to existing measures already installed/ implemented. The risk evaluation after

implementation of recommendation/ risk reduction measures shall be carried out to demonstrate

that the risk shall be reduced to ALARP region and the study recommendations are adequate for

the project.

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5. DETAIL STUDY INPUTS

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Isolatable section Name

Description Scenario Diameter

m Length

m Pressure kg/cm2

Temp C

Capacity, KL

Mass flow rate/ capacity

Density Kg/m3

Static inventory

kg

Isolation time

s

Dynamic inventory,

kg

Total Inventory, kg

Dyke details

m3/hr Kg/s Dyke

height, m

Area, m2

Volume, m3

PIPELINES

IS-1 Feeding pipeline to Tank-1 FO 180

LEAK 0.4064 450 11.67 47.5 NA 700 192.50 990 57759.678 1800 4326.84 62086.52 NA NA NA

RUPTURE 0.4064 450 11.67 47.5 NA 700 192.50 990 57759.678 120 23100.00 80859.68 NA NA NA

IS-2 Feeding pipeline to Tank-2 FO 380

LEAK 0.4064 520 11.67 47.5 NA 700 192.50 990 66744.517 1800 4326.84 71071.36 NA NA NA

RUPTURE 0.4064 520 11.67 47.5 NA 700 192.50 990 66744.517 120 23100.00 89844.52 NA NA NA

IS-3 Feeding pipeline to Tank-3 HSD

LEAK 0.3048 470 11 30 NA 540 123.00 820 28106.793 1800 3975.84 32082.63 NA NA NA

RUPTURE 0.3048 470 11 30 NA 540 123.00 820 28106.793 120 14760.00 42866.79 NA NA NA

IS-4 Feeding pipeline to Tank-7 HFHSD

LEAK 0.3048 475 11 30 NA 540 126.00 840 29098.626 1800 3975.84 33074.47 NA NA NA


IS-5 Pump suction line from Tank-1 FO 180

LEAK 0.4064 77 2 30 NA 950 261.25 990 9883.323 1800 1791.47 11674.79 NA NA NA


IS-6 Pump suction line from Tank-2 FO 380

LEAK 0.4064 80 2 30 NA 410 112.75 990 10268.387 1800 1791.47 12059.86 NA NA NA


IS-7 Pump suction line from Tank-3 HSD

LEAK 0.3048 120 2 30 NA 700 159.44 820 7176.202 1800 1695.55 8871.75 NA NA NA


IS-8 Pump suction line from Tank-7 HFHSD

LEAK 0.3048 140 2 30 NA 300 70.00 840 8576.437 1800 1695.55 10271.98 NA NA NA


IS-9 Pump discharge line from Pump-102 A/ B FO-180

LEAK 0.3048 380 12 30 NA 950 261.25 990 27435.847 1800 4387.57 31823.42 NA NA NA

RUPTURE 0.3048 380 12 30 NA 950 261.25 990 27435.847 120 31350.00 58785.85

NA NA NA

IS-10 Pump discharge line from Pump-101 A/B FO-380

LEAK 0.254 380 5.4 30 NA 410 112.75 990 19052.672 1800 2943.54 21996.21 NA NA NA

RUPTURE 0.254 380 5.4 30 NA 410 112.75 990 19052.672 120 13530.00 32582.67

NA NA NA

IS-11 Pump discharge line from Pump-201 A/B HSD

LEAK 0.3048 380 5.8 30 NA 700 159.44 820 22724.641 1800 2887.25 25611.90 NA NA NA

RUPTURE 0.3048 380 5.8 30 NA 700 159.44 820 22724.641 120 19133.33 41857.97 NA NA NA

IS-12 Pump discharge line from Pump-202A HFHSD

LEAK 0.2032 380 4 30 NA 300 70.00 840 10346.178 1800 2397.80 12743.98 NA NA NA


IS-13 Inter tank transfer line for FO-380 tanks

LEAK 0.3048 280 5.4 30 NA 410 112.75 990 20215.887 1800 2943.54 23159.43 NA NA NA

RUPTURE 0.3048 280 5.4 30 NA 410 112.75 990 20215.887 120 13530.00 33745.89 NA NA NA

STORAGE TANKS

IS-14 TANK-1 FO-180

LEAK 24.4 14.63 atm 30 7200 NA NA 990 NA NA NA NA 1.8 6167 8050

RUPTURE 24.4 14.63 atm 30 7200 NA NA 990 NA NA NA NA 1.8 6167 8050


IS-15 TANK-2 FO-380




IS-16 TANK-3 HSD




IS-17 TANK-4 FO-380 RUPTURE 15.24 14.63 atm 30 3200 NA NA 990 NA NA NA NA 1.4 3006 3490

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Isolatable section Name

Description Scenario Diameter

m Length

m Pressure kg/cm2

Temp C

Capacity, KL

Mass flow rate/ capacity

Density Kg/m3

Static inventory

kg

Isolation time

s

Dynamic inventory,

kg

Total Inventory, kg

Dyke details

m3/hr Kg/s Dyke

height, m

Area, m2

Volume, m3



IS-18 TANK-7 HF HSD

LEAK 24.85 16 atm 30 8050 NA NA 840 NA NA NA NA 1.8 6167 8050

RUPTURE 24.85 16 atm 30 8050 NA NA 840 NA NA NA NA 1.8 6167 8050

LEAK 24.85 16 atm 30 8050 NA NA 840 NA NA NA NA 1.8 6167 8050

IS-19 TANK-8 FO-380

RUPTURE 30 16 atm 30 6900 NA NA 990 NA NA NA NA 2.8 2816 6920

LEAK 30 16 atm 30 6900 NA NA 990 NA NA NA NA 2.8 2816 6920

RUPTURE 30 16 atm 30 6900 NA NA 990 NA NA NA NA 2.8 2816 6920

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6. STUDY RESULTS

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The following table presents the impact distances due to the event consequences

Table 5 CONSEQUENCE RESULTS

Isolatable Section

Scenario Description

Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)

Radiation Effects: Jet Fire Ellipse

Radiation Effects: Late pool Ellipse

Vapor Cloud explosion 100% LFL Ellipse

Distance in meters Distance in meters Distance in meters Over

pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D

IS-1

Feeding pipeline to Tank-1 FO

180

LEAK 22.5 21.9189

4 NR NR 80.3881 98.4912 0.02068 NR NR

12.5 NR NR 47.73 60.2262 0.1379 NR NR

37.5 NR NR NR NR 0.2068 NR NR

RUPTURE 9.74912 9.77656

4 NR NR 97.4916 107.277 0.02068 NR NR

12.5 NR NR 52.8124 53.7135 0.1379 NR NR


IS-2

Feeding pipeline to Tank-2 FO

380

LEAK 22.5 21.9189

4 NR NR 80.3881 98.4912 0.02068 NR NR

12.5 NR NR 47.73 60.2262 0.1379 NR NR


RUPTURE 8.92527 8.91054

4 NR NR 103.826 114.288 0.02068 NR NR

12.5 NR NR 56.1793 57.0383 0.1379 NR NR


IS-3 Feeding

pipeline to Tank-3

LEAK 17.9817 24.7552 4 9.54032 11.1854 81.6084 101.057 0.02068 18.5285 34.1709

12.5 7.17593 8.12563 45.2869 56.2447 0.1379 12.2082 23.6692

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Isolatable Section


Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)





pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D

HSD 37.5 5.54125 6.1931 NR NR 0.2068 11.7087 22.8391

RUPTURE 7.03067 6.95071

4 6.35047 6.18921 131.627 149.554 0.02068 NR NR

12.5 4.63957 4.4744 67.7326 68.6548 0.1379 NR NR

37.5 3.47678 3.04087 NR NR 0.2068 NR NR

IS-4

Feeding pipeline to

Tank-7 HFHSD

LEAK 17.9817 24.7552

4 9.54032 11.1854 81.6084 101.057 0.02068 18.5285 34.1709

12.5 7.17593 8.12563 45.2869 56.2447 0.1379 12.2082 23.6692

37.5 5.54125 6.1931 NR NR 0.2068 11.7087 22.8391

RUPTURE 6.99263 6.90689

4 6.31569 6.15925 133.185 151.301 0.02068 NR NR

12.5 4.61008 4.45196 68.6278 69.7497 0.1379 NR NR

37.5 3.45594 3.03014 NR NR 0.2068 NR NR

IS-5

Pump suction line from Tank-1 FO 180

LEAK 6.22664 6.90144

4 NR NR 49.8988 55.1685 0.02068 NR NR

12.5 NR NR 25.0734 27.6257 0.1379 NR NR


RUPTURE 7.15284 7.06644

4 NR NR 71.3158 78.4995 0.02068 NR NR

12.5 NR NR 36.8102 37.8204 0.1379 NR NR


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Isolatable Section


Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)





pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D

IS-6

Pump suction line from Tank-2 FO 380

LEAK 6.22664 6.90144

4 NR NR 49.8988 55.1685 0.02068 NR NR

12.5 NR NR 25.0734 27.6257 0.1379 NR NR


RUPTURE 7.05008 6.9617

4 NR NR 59.3288 65.0692 0.02068 NR NR

12.5 NR NR 30.0449 31.484 0.1379 NR NR


IS-7

Pump suction line from Tank-

3 HSD

LEAK 6.13762 6.86718

4 2.30849 2.26463 53.2513 60.8622 0.02068 NR NR

12.5 NR NR 24.8724 27.3396 0.1379 NR NR


RUPTURE 4.97 4.88

4 4.42 4.75 107.02 122.1 0.02068 NR NR

12.5 3.08 3.4 52.75 53.54 0.1379 NR NR


IS-8

Pump suction line from Tank-

7 HFHSD

LEAK 6.13762 6.86718

4 2.30849 2.26463 53.2513 60.8622 0.02068 NR NR

12.5 NR NR 24.8724 27.3396 0.1379 NR NR


RUPTURE 4.66206 4.57433 4 4.15148 4.57186 90.0616 102.963 0.02068 NR NR

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Isolatable Section


Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)





pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D

12.5 2.82325 3.26532 43.2389 44.1532 0.1379 NR NR


IS-9

Pump discharge line from

Pump-102 A/ B FO-

180

LEAK 22.32 21.9745

4 NR NR 81.1215 99.7418 0.02068 NR NR

12.5 NR NR 48.3173 61.2999 0.1379 NR NR


RUPTURE 8.18818 9.15

4 NR NR 98.733 108.725 0.02068 NR NR

12.5 NR NR 52.8837 53.658 0.1379 NR NR


IS-10


Pump-101 A/B FO-380

LEAK 10.9302 13.0136

4 NR NR 62.9336 71.7176 0.02068 NR NR

12.5 NR NR 33.8672 38.3925 0.1379 NR NR


RUPTURE 4.34645 4.28864

4 NR NR 89.1968 98.603 0.02068 NR NR

12.5 NR NR 45.7338 46.4754 0.1379 NR NR


IS-11 Pump

discharge line from

LEAK 11.18 14.7781 4 6.30038 7.0403 67.4643 79.4298 0.02068 18.1808 17.3965

12.5 4.59302 5.02337 34.3204 39.1316 0.1379 12.1182 11.9151

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Isolatable Section


Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)





pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D

Pump-201 A/B HSD

37.5 3.23466 3.6116 NR NR 0.2068 11.639 11.4819

RUPTURE 5.31622 5.21941

4 4.75588 4.98924 128.701 146.462 0.02068 NR NR

12.5 3.36744 3.58832 65.3108 66.2036 0.1379 NR NR

37.5 NR 2.36956 NR NR 0.2068 NR NR

IS-12


Pump-202A

HFHSD

LEAK 8.5614 10.6594

4 4.5751 4.86792 61.3579 71.1812 0.02068 NR 16.8757

12.5 3.23437 3.3827 30.0043 33.3237 0.1379 NR 11.7803

37.5 NR 2.12121 NR NR 0.2068 NR 11.3775

RUPTURE 3.30442 3.28362

4 2.7325 3.39944 92.2273 105.668 0.02068 NR NR

12.5 NR 2.20908 43.8026 44.8548 0.1379 NR NR


IS-13

Inter tank transfer

line for FO-380 tanks

LEAK 10.9302 13.0136

4 NR NR 62.9336 71.7176 0.02068 NR NR

12.5 NR NR 33.8672 38.3925 0.1379 NR NR


RUPTURE 5.83552 5.74107

4 NR NR 77.6201 85.631 0.02068 NR NR

12.5 NR NR 39.7657 40.7532 0.1379 NR NR


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Isolatable Section


Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)





pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D

IS-14 TANK-1 FO-

180

LEAK 4.53793 4.89137

4 NR NR 43.3179 47.2782 0.02068 NR NR

12.5 NR NR 21.6396 24.2693 0.1379 NR NR


RUPTURE 25.281 25.4313

4 NR NR 91.5886 101.736 0.02068 NR NR

12.5 NR NR 45.306 46.1459 0.1379 NR NR


IS-15 TANK-2 FO-

380

LEAK 4.53793 4.89137

4 NR NR 43.3179 47.2782 0.02068 NR NR

12.5 NR NR 21.6396 24.2693 0.1379 NR NR


RUPTURE 26.0936 26.2471

4 NR NR 91.5886 101.736 0.02068 NR NR

12.5 NR NR 45.306 46.1459 0.1379 NR NR


IS-16 TANK-3

HSD

LEAK 4.29844 4.72685

4 NR NR 46.1234 51.9181 0.02068 NR NR

12.5 NR NR 21.2291 23.8639 0.1379 NR NR


RUPTURE 20.1577 20.3198 4 NR NR 73.0366 84.3184 0.02068 32.9986 33.1017

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Isolatable Section


Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)





pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D

12.5 NR NR 31.9328 33.0385 0.1379 23.3657 23.3923

37.5 NR NR NR NR 0.2068 22.6043 22.6249

IS-17 TANK-4 FO-

380

LEAK 4.46004 4.80859

4 NR NR 42.9192 46.7964 0.02068 NR NR

12.5 NR NR 21.3916 24.0485 0.1379 NR NR


RUPTURE 20.0987 20.2533

4 NR NR 68.2319 75.9524 0.02068 NR NR

12.5 NR NR 31.9328 33.1373 0.1379 NR NR


IS-18 TANK-7 HF

HSD

LEAK 4.29844 4.72685

4 NR NR 46.1234 51.9181 0.02068 NR NR

12.5 NR NR 21.2291 23.8639 0.1379 NR NR


RUPTURE 26.1643 26.3202

4 NR NR 97.6319 112.227 0.02068 33.8411 34.0684

12.5 NR NR 45.306 46.2026 0.1379 23.5838 23.6427

37.5 NR NR NR NR 0.2068 22.7731 22.8186

IS-19 TANK-8 FO-

380 LEAK 4.53793 4.89137

4 NR NR 43.3179 47.2782 0.02068 NR NR

12.5 NR NR 21.6396 24.2693 0.1379 NR NR

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Isolatable Section


Release category

Flash Fire Effects:

Radiation Levels

(kW/m2)





pressure level bar

Distance in meters

2F 5D 2F 5D 2F 5D 2F 5D


RUPTURE 24.9805 25.1277

4 NR NR 66.46 73.9844 0.02068 NR NR



Note- NR in the table refers to distance Not Reached

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IMPACT ANALYSIS

This step identifies the hazard damage and fatality probability, based on hazard type, to personnel

at a range of distances.

Flash Fire Cases:

Flash Fire is usually dispersion case, where the extent of cloud until the flammability limits (LFL) is

measured. The important factor in measuring the extent of cloud is atmospheric stability & wind

speed. As the wind speed increases, the cloud tends to move farther down & gets diluted which

results in lower quantity of material in the flammability limits i.e. lower strength of flash fire/VCE.

The maximum LFL distance of 26.32 m was observed for IS-18 Catastrophic rupture of HFHSD tank

7 (highlighted) at 5 D weather condition.

Jet Fire cases:

The important factor contributing jet fire is the release rate which in turn depends on the process

parameters (Pressure, Temperature, etc.). If the release rate is low, the damage distance will not

be enough to cause considerable consequences, as shown in certain cases mentioned above.

The highest damage distances for Jet Fire are for IS-3 and 4, Leak in the feeding pipeline to Tank-3

and Tank-7 respectively (highlighted). First degree burns can be experienced upto a distance of

11m. Second degree burns (piloted ignition of wood, etc.) can be experienced up to a distance of

8m (12.5Kw/m2); 99% fatality (damage to process equipment) can be experienced up to a

distance of 6m.

Pool Fire cases:

Pool fire depends on factors like quantity of liquid released, availability of liquid drainage or dyke,

material released, etc. the higher the quantity released and lower then evaporation rate, the

higher will be the damage distances for pool fire. The highest damage distances of pool fire are for

IS-4, Rupture of feeding pipeline to Tank-7 HFHSD (highlighted). First degree burns can be

experienced upto a distance of 151m. Second degree burns (piloted ignition of wood, etc.) can be

experienced up to a distance of 69m (12.5Kw/m2) and 99% fatality is not reached.

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Explosion Cases:

Vapour cloud explosion is the result of flammable materials in the atmosphere, a subsequent

dispersion phase, and after some delay an ignition of the vapour cloud. The highest damage

distances for overpressure are for IS-3 and 4, Leak in the feeding pipeline to Tank-3 and Tank-7

respectively (highlighted).

Shattering of window glass can be experienced upto a distance of 34m. Repairable damage to

building and houses can be experienced up to a distance of 23m and pull away of steel frame

buildings from foundations and little damage for heavy machines (3000 lb) in industrial building

shall be suffered up to a distance of 22m.

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7. RISK PRESENTATION

Risk is often defined as a function of the likelihood that a specified undesired event will occur, and

the severity of the consequences of that event. Risk is derived from the product of likelihood and

potential consequence. Risk in general is a measure of potential economic loss or human injury in

terms of the probability of the loss or injury occurring and magnitude of the loss or injury if it

occurs.

(Severity,Frequency)Risk f

Quantification of effects of the hazardous event was done using the event tree approach in which

all the possible outcomes of the hazardous event were considered and the likelihood of each type

of end event determined. This step in the process involves the use of consequence modelling to

predict both physical phenomena such as dispersion, size and duration of fires, overpressures due

to explosions, and the performance of equipment and systems such as availability of a fire & gas

detection system, availability of emergency shutdown system, and availability of fire protection

system. The end result of this phase of the assessment is a series of “end events”, together with

their estimated frequency of occurrence.

The risk modelling has been performed using DNV PHAST RISK 6.7 software. Thereby, the details

of the input data used for the risk modelling such as vulnerability criteria, ignition probability and

occupancy data are given in the QRA Assumption Register (Annexure 2).

The results of a QRA are expressed using Individual Risk Contours and Societal Risk Graphs given in

this section of the report.

7.1 LOCATION SPECIFIC INDIVIDUAL RISK

The term “Location-Specific Individual Risk (LSIR)” is used for the calculations of the risk of fatality

for someone at a specific location, assuming that the person is always present at the location and

therefore, is continuously exposed to the risk at that location. This makes the LSIR a measure of

the geographic distribution of risk, independent of the distribution of people at that location or in

the surrounding area. The LSIR is presented as iso-risk contours (Figure 3) on a map of the location

of interest.

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7.2 RISK RESULTS

Location Specific Individual Risk (LSIR) is acquired directly from PHAST Risk software. The LSIR is

the individual risk at different locations based upon the assumption that an unprotected individual

is present at an unprotected location exposed to the risk for 24 hours a day, 365 days.

Individual Risk = Location Specific Individual risk * Occupancy factor

The Individual Risk represents the frequency of an individual dying due to loss of containment

events (LOCs). The individual is assumed to be unprotected and to be present during the total

exposure time.

Figure 3 Location Specific Individual Risk Contour

The Societal Risk represents the frequency of having an accident with N or more people being

killed simultaneously. The people involved are assumed to have some means of protection. The

Societal Risk is presented as an F-N curve (Figure 4), where N is the number of deaths and F the

cumulative frequency of accidents with N or more deaths.

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Figure 4 Soceital Risk – FN Curve

RISK RANKING

The following graph shows the top 10 risk contributing scenarios for the proposed Bunkering

facility.

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8. RISK ACCEPTANCE CRITERIA

In India, there is yet to define Risk Acceptance Criteria. However, in IS 15656 – Code of Practice for

Hazard Identification and Risk Analysis, the risk criteria adopted in some countries are shown.

Extracts for the same is presented below:

Table 6 Risk Criteria

Authority and Application Maximum Tolerable Risk

(per year)

Negligible Risk

(per year)

VROM, The Netherlands (New) 1.0E-6 1.0E-8

VROM, The Netherlands (existing) 1.0E-5 1.0E-8

HSE, UK (existing-hazardous industry) 1.0E-4 1.0E-6

HSE, UK (New nuclear power station) 1.0E-5 1.0E-6

HSE, UK (Substance transport) 1.0E-4 1.0E-6

HSE, UK (New housing near plants) 3.0E-6 3.0E-7

Hong Kong Government (New plants) 1.0E-5 Not used

Figure 5 ALARP

Based on the input conditions such as process parameters, climatological condition, etc., the risk

posed by all the Loss of containment (LOC) Scenarios covered under this project, it is observed

that the individual risk per annum is found to fall in the Acceptable limit as per HSE UK risk

acceptance criteria.

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9. PROPOSED RISK REDUCTION MEASURES BY HPCL

The proposed Risk mitigation measures for the Bunkering facility by HPCL is as follows

Butcher Island (Jawahar Dweep) is having only Petroleum facilities and is Restricted Area. Entire

land at Butcher Island belongs to Mumbai Port Trust (MbPT). Further, there are no other facilities

adjoining the tank farm proposed to be operated by HPCL, and is vacant.

In order to take care of above deviations, HPCL have proposed

Sprinkler System – 2 rings for all Tanks and

Remote operated Oscillating monitors on the side towards boundary walls, within the Dyke

with isolation valve or ROV outside the tank farm.

In line with OISD 117 and 244, HPCL have proposed Hydrants at distance of 30 m and

Monitors at a distance of maximum 45 m.

Apart from above, Fire-fighting Facilities available with MbPT shall be allowed to be used by HPCL

as per Agreement.

Further, following improvement in proposed Layout is done after discussions with PESO officials on 9th Sept., 2016:

1. Product pump-house is made independent and shall now shall be in exclusive control of

HPCL.

2. Entire boundary is segregated with gates at both ends of the road.

3. It is ensured that all the distances specified as per OISD are met. However, distance to

boundary from tank is being put up as exception.

4. All the inter tank distances and other salient distances clearly shown on the layout.

5. Agreement made between Mbpt and HPCL with regard to extension of fire services by

Mbpt to HPCL premises is enclosed. Also, enclosed details of the fire fighting available at

Mbpt end. It is confirmed that the capacity of fire pumps at MbPT are adequate.

6. Provision has been made that Fire pumps at Mbpt can be triggered from within HPCL

premises in case of emergency.

7. Capacity of tank no.8 is reduced and dyke area is increased, so that tank to dyke wall

distance is as per OISD norms.

8. Access road all round tanks (Dyke-I) provided, for access to fire-fighting facilities.

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SALIENT FEATURES OF LAYOUT, SAFETY CONSIDERATIONS, DETAILS OF FIRE-FIGHTING FACILITIES & SAFETY FITTINGS ON TANKS:

Salient features of Layout, Safety considerations, Details of Fire Fighting Facilities and Safety Fittings on Tanks, are given hereunder –

HPCL Tank farm shall have Hook-up from the Mumbai Port Trust’s Main Fire Hydrant Pipe-

line of 30” dia. As per Agreement, MbPT has given permission to HPCL for tapping and

using their Hydrant system.

Fire Fighting Pumps: There are 4 Pumps of 626 m3/hr capacity each and 2 Pumps of 545

m3/hr, with Head / Pressure of 15 kg/cm2. It is confirmed that MbPT’s Fire Pump

capacities are adequate to take care of HPCL’s Bunkering Terminal requirement.

All tanks (irrespective of Petroleum class) shall be provided with 2 rings of fixed Water

Sprinkler System.

All tanks shall be provided with Static Foam Pourer System, designed in line with OISD.

Details of Foam Pourers for each tank are given in Annexure. Total 7000 ltrs. of static foam

storage Tank is proposed, which is in line with requirement. Detailed Working is as per

Annexure.

Access road all round tanks provided, for access to fire-fighting facilities (motorable road

not possible due to physical constraints, as it is old installation).

HPCL have proposed Oscillating Monitors between tank & boundary wall, with isolation

valve or ROV outside the tank farm.

HPCL have proposed Hydrants at distance less than 30 m and Monitors at a distance of

maximum 45 m., which is in line with OISD 117 and 244.

Also, as per M B Lal Committee Recommendations (MBLC), HPCL have considered the dyke

volume increased to 110% of the largest tank.

For Tank No. 8, as limited dyke area is available, HPCL have proposed dyke wall height of

2.8 mtrs. (9 ft., 2 inch). HPCL seek approval as per Petroleum Rules 2002, under Chapter

XII-Exemption, Article -6.

Wherever Dyke height is more than 2 mtrs, suitable Railings are proposed. Also, in case of

Dyke Wall width less than 0.6 mtr., suitable Railings shall be provided.

HPCL have also proposed ROV / MOVs on each tanks, as per MBLC. The same is shown in

Layout.

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HPCL have proposed for Provision so that Fire pumps at Mbpt can be triggered from within HPCL premises in case of emergency.

HPCL have proposed to install Radar Gauges on all the Storage tanks and also Tank Farm

Management System.

All the Pumps, Equipment, Electrical Installations etc. shall meet OISD requirements.

Wherever necessary, Electrical fittings shall be Flame-proof.

HPCL shall provide Flow-meters on the Delivery Lines, with display in Operating room and

On-off control “at Site” and “off-site”, to control the discharge.

HPCL propose to conduct Quantitative Risk Analysis (QRA) for the deviations to OISD

distance norms, and all mitigating measures would be taken as per recommendations.

HPCL have proposed to incorporate standard SOPs are in place for Receipt and Delivery

Operations including as proposed in the Hazop.

The following table provides the proposed fire protection system for the Bunkering facility

DETAILS OF PORTABLE / TROLLEY-MOUNTED FIRE-FIGHTING SYSTEM (As per OISD 117)

Area Description Fire Extinguisher

10kg DCP 25kg DCP (trolley)

Tank No.8 2

Tank Farm No.8 2

Tank No.6 2

Tank Farm No.6 2

Tank No.1 2

Tank Farm No.1 2

Tank No.2 2

Tank No.7 2

Tank Farm No.2 and 7 2

Tank No.3 2

Tank Farm No.3 2

Tank No.4 2

Tank Farm No.4 2

Tank No.5 2

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Area Description Fire Extinguisher

10kg DCP 25kg DCP (trolley)

Tank Farm No.5 2

Shore crew quarters canteen

14

TOTAL 30 14

DETAILS OF FIRE-FIGHTING FACILITIES

Sl. No. Description Qty.

Fire and Foam Monitors and Hydrants

1 Fire Water/ Foam Monitors 14

2 Fire/ Foam Oscillating Monitors 12

3 Hydrants 10

Portable Foam system

1 Portable foam monitor (2400 lpm) 2

Foam Compound Trolley

1 200/210 litres 2

Fire extinguishers (10 kg)

DCP

1 Tank 1 2

2 Tank 2 2

3 Tank 3 2

4 Tank 4 2

5 Tank 7 2

6 Tank 8 2

7 Oil Pump House 12

8 DG Room 2

CO2 (4.5 Kg)

1 Panel room 8

2 DG Room 1

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Sl. No. Description Qty.

Fire extinguishers (25 kg)

DCP

1 Tank Farm 1,2 & 7 2

2 Tank Farm 3 2

3 Tank Farm 4 2

4 Tank Farm 8 2

Foam Pourers

1 Tank 1 3

2 Tank 2 4

3 Tank 3 2

4 Tank 4 2

5 Tank 7 3

6 Tank 8 5

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10. CONCLUSION AND RECOMMENDATIONS

CONCLUSION

Based on the information provided to iFluids Engineering team and the outcome of the QRA

report, following conclusions are made,

1. All the Distance norms are compiled including the inter tank distances, except following

Distance between Tank (shell) to Boundary Wall with respect to tank No. 2, 3, 4, 7 & 8; which

is specified (D/2 or min. 20 mtrs.) as per norms.

Distance between Tank No. 3 (Class “B”) and Tank No. 7 (Class “C”); which is specified as “D”

or 30 mtr, whichever is more.

The proposed distances inbetween the tanks are as follows

The Installation is pre-OISD set-up, thus not meeting above stipulations and all round

access to tank-farm, due to physical constraints. The entire land at Butcher Island belongs

to Mumbai Port Trust (MbPT) and it is restricted area. There is no other facility in the

adjacent land and is vacant.

Proposed pump operator cabin and control room to be built as a blast proof structure as

per OISD-STD-163 norms.

Medium velocity water sprinkler systems to be provide for all the tanks.

Remote operated HVLR covering Tank 3 and Tank 7 on all sides to be provided.

1 2 3 4 5 6 7 8 9 10 11

1 Tank 1(Class C) 27 58.5 38 59.5 72 51 145 30 23 20

2 Tank 2(Class C) 27 38 60 94.2 122.7 12 194 68 73 14

3 Tank 3(Class B) 58.5 38 29 75.1 211.7 17 209 92 80 22

4 Tank 4(Class C) 38 60 29 30.4 171.7 56 170 69 43 7.5

5 Tank 5(Class C) 59.5 94.2 75.1 30.4 55.8 99.5 134.5 65 26.3 30.7

6 Tank 6 72 122.7 211.7 171.7 55.8 72.5 59.6 29.6 31 21.8

7 Tank 7(Class C) 51 12 17 56 99.5 72.5 220 95 96 13

8 Tank 8(Class C) 145 194 209 170 134.5 59.6 220 93 104 14.72

9Tank Farm

Panel Room30 68 92 69 65 29.6 95 93 3.7 11

10 Oil Pump House 23 73 80 43 26.3 31 96 104 3.7 20

11 Boundary Wall 20 14 22 7.5 30.7 21.8 13 14.72 11 20

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As per OISD-STD-244, Clause 6.4.4 – 3d, minimum distance between tank shell and the toe

of the dyke wall shall not be less than half the height of the tank.Following tanks are not

meeting with the stated clause,

Tank No.3 – 6m on the west side

Tank No.4 – 5.2 m in the north side

Tank No.7 – 7m in the west, 6m in the North West and 6m in the North East

side.

Operating level of the tank to be maintained not exceeding twice the distance between the tank

shell and toe of the dyke wall for the above tanks. Consider providing high level alarms configured

at particular height for the above tanks (Tank No.3 -12m, Tank No.4 -10.4m and Tank No.7 – 12m).

RECOMMENDATIONS

It is suggested to implement Risk control measures listed below for Risk Improvement of the

Bunkering facilities:

1. Ensure all the import/export lines to be adequately designed for the maximum pressure

source.

2. Ensure all the import/export lines are pressure tested to rated pressure before

commissioning or after any maintenance activity.

3. Provide ROV-TO3B/MOV-TO3B open feedback permissive for starting P-201 A/B pumps.

4. Provide MOV-07B open fed back permissive for starting P-202 A pump.

5. Provide MOV-01B open feed back permissive for starting P-102 A/B.

6. Provide MOV-04B/MOV-08B/MOV-02B/1003 open feed back permissive for starting the

pumps P-101 A/B.

7. Provide ROV-TO3B/MOV-TO3B close feed back trip for the pumps P-201 A/B.

8. Provide discharge PT’s for the pumps with high pressure alarms to avoid blocked discharge

running conditions due to multiple loop operations and low pressure alarm on running

condition to identify any leak scenario.

9. Provide low suction pressure alarm and low low pressure trip for the pump to avoid dry

run operation.

10. Ensure low level, low low level, high level, high high level indications, alarms, trips are

configured as per P&ID.

11. Ensure SOP is developed/displayed for critical operations.

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12. Ensure proper training/regural assessment fot the operation crew.

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11. LIST OF REFERENCE DOCUMENTS / STANDARDS

1. Guideline of Quantitative Risk Assessment - PGS 3 [Purple book]

2. Methods for the determination of possible damage – CPR 16E [Green book]

3. DNV SAFETI manual

4. UK HSE Risk Manual

5. DNVGL,PHAST-RISK(Safeti),Version6.7,

http://www.dnv.com/services/software/products/safeti/safeti/index.asp

6. www.meteoblue.com

7. OISD-Oil Industry Safety Directorate

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ANNEXURE-I

CONSEQUENCE CONTOURS

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This annexure presents the consequence contours of all the tanks. The annexure also contains

maximum contours for the transfer pipelines representative for tank feed line, Pump suction line,

pump discharge line and inter tank transfer pipe line.

1. FLASH FIRE CONSEQUENCES

PIPLINE CONSEQUENCES

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STORAGE TANKS

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JET FIRE SCENARIOS

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POOL FIRE SCENARIOS

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ANNEXURE-II

QRA ASSUMPTION REGISTER

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QUANTITATIVE RISK

ASSESSMENT-

ASSUMPTION REGISTER

Hindustan Petroleum Corporation Limited

BUNKERING FACILITIES AT JAWAHAR DWEEP (BUTCHER ISLAND) AT

MUMBAI

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Quantitative Risk Assessment –Assumptions Register


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DOCUMENT REVISION SHEET

REPORT TITLE Quantitative Risk Assessment- Assumption Register

PROJECT Bunkering facilities at Jawahar Dweep

CLIENT Hindustan Petroleum Corporation Limited

HSE CONSULTANT iFluids Engineering

00 03-12-16 Issued for Review SPK VJM

Rev Date Comments / Nature of Changes Prepared by Reviewed by Approved By (HPCL)

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Table of Contents Page

1. INTRODUCTION ..................................................................................................................... 3 1.1 Project Background ..................................................................................................... 3 1.2 Purpose of this Document ............................................................................................ 4

2. DEFINITIONS AND ABBREVIATIONS ..................................................................................... 4 2.1 Definitions ................................................................................................................... 4 2.2 Abbreviations .............................................................................................................. 4

3. QRA METHODOLOGY ............................................................................................................. 6 3.1 Hazard Identification ................................................................................................... 6 3.2 QRA Input Data ............................................................................................................ 7 3.3 Consequence Analysis .................................................................................................. 7 3.4 Frequency Analysis ...................................................................................................... 7 3.5 Risk Assessment .......................................................................................................... 7 3.6 Risk Evaluation ............................................................................................................ 8 3.7 Risk Reduction Measures ............................................................................................. 8

4. QRA ASSUMPTION SHEETS .................................................................................................... 8 4.1 QRA Project Scope ....................................................................................................... 9 4.2 Meteorological Conditions .......................................................................................... 11 4.3 Loss of Containment Scenarios ................................................................................... 13 4.4 Material Composition, Process Conditions, Inventory & Discharge Coefficient .............. 14 4.5 Software Used ........................................................................................................... 15 4.6 Release Size, Height, Duration & Direction .................................................................. 16 4.7 Failure Frequency ...................................................................................................... 17 4.8 Ignition Probability .................................................................................................... 18 4.9 Occupancy Data & Population ..................................................................................... 19 4.10 Dyke Area .................................................................................................................. 20 4.11 Blocking factors ........................................................................................................ 21 4.12 Impact Criteria .......................................................................................................... 22 4.13 Risk Acceptance Criteria ............................................................................................ 23

5. LIST OF REFERENCE DOCUMENTS / STANDARDS ........................................................ 24

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1. INTRODUCTION

Hindustan Petroleum Corporation Limited has awarded iFluids Engineering to carry out Quantitative

risk assessment study for their Proposed Bunkering facility at Jawahar Dweep. The contract identifies

the methodology proposed by iFluids Engineering and accepted by HPCL for the completion of the

Quantitative Risk Assessment Study (QRA) study.

This document describes the methodology and assumptions that will be considered for the completion

of the Quantitative Risk Assessment (QRA) Study of the scope.

1.1 Project Background

Jawahar Dweep is currently being used exclusively for Handling of Petroleum Products by Mumbai

Port Trust and it has facilities for unloading of Crude Oils, Import & Export of Finished Oils. Total 4 nos.

of Jetties, all connected to HPC & BPC Refineries thro’ sub-sea pipe-line

Exclusive pipe-lines for White Oils and Black Oils, are connected to HPC/BPC Refineries

Tri-partite Agreement signed between Mumbai Port Trust (MbPT), HPC & BPC for setting-up of

Bunkering facilities at Jawahar Dweep.

Mumbai Port Trust (MbPT) has offered HPCL total 6 nos. Tanks, aggregating approx. 34 TKL of

tankages along with Pump-House and connected Pipe-lines

Agreement is being signed for taking-over of Tank-farm area on long lease of 30 years.

Entire land on Jawahar Dweep (Butcher Island) belongs to MbPT.

HPCL is planning to develop exclusive Bunkering Terminal by Refurbishing tanks, Pipe-line

modifications, and Revamp other allied facilities including fire-fighting etc.

The details of those six tanks are as follows

HPCL’S BUNKERING TERMINAL – OPERATIONAL PART:

Products (i.e. FO-380 and HFHSD) shall be received through Mumbai Port Trust’s Black oil and White Oil pipe-lines

respectively, from the HPCL Mahul Refinery. Product may also be received through Pipe-line from Vessels berthing at

Jawahar Dweep/ Pirpau.

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Normal pipe-line contents in these MBPT’s pipe-line are FO-180 and HSD respectively. Accordingly, it is envisaged to

designate one tank each for storage of pipe-line content of FO-180 and HSD. Post receipt operations, this pipe-line content

will be pushed-back to the pipe-line.

Delivery of the products (FO-380 and HFHSD) shall be primarily through MbPT Bunkering line in the barges berthed at JD-2.

1.2 Purpose of this Document

This register is the basis of agreement between HPCL and iFluids Engineering on the assumptions

necessary to be made prior to the commencement of the Quantitative Risk Assessment (QRA) study

for the “Bunkering Facilities at Jawahar Dweep” project.

This document presents the assumptions made prior to starting the QRA study. Any further

assumptions that may be necessary in order to develop the study will be clearly presented in the QRA

study report.

2. DEFINITIONS AND ABBREVIATIONS

2.1 Definitions

COMPANY Hindustan Petroleum Corporation Limited

CONSULTANT iFluids Engineering, appointed by the COMPANY to perform PROJECT.

CONTRACT The contract between COMPANY and CONSULTANT for PROJECT

PROJECT Bunkering Facilities at Jawahar Dweep

SERVICES Services being provided by iFluids Engineering as per the CONTRACT for the

PROJECT

2.2 Abbreviations

ALARP As Low as Reasonably Practicable

DNV Det Norske Veritas

FO Furnace Oil

HFHSD High Flash High Speed Diesel

HSE Health safety and Environment

HPCL Hindustan Petroleum Corporation Limited

HSD High Speed Diesel

IRPA Individual Risk Per Annum

IS Isolatable Section

JD Jawahar Dweep

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LFL Lower Flammability Limit

LOC Loss of Containment

LSIR Location Specific Individual Risk

QRA Quantitative Risk Assessment

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3. QRA METHODOLOGY

This section presents a brief description of the approach and steps followed in the QRA study.

The QRA Study included the following steps:

Identification of the hazardous events associated with the project facility;

Consequence modelling of the physical effects;

Estimation of total failure frequencies;

Evaluation / assessment of the risks arising from the pipeline network with respect to UK HSE Risk

Acceptance Criteria;

Recommending risk reduction measures.

The overall QRA methodology is shown in Figure 1 and is described in more detail in the subsequent

sections.

Figure 1: QRA Methodology

3.1 Hazard Identification

The hazardous scenarios considered in the QRA for the project facility will be identified based on the

properties of the materials handled and the identification of the potential hazards in the pipeline

systems which could lead to loss of containment events.

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3.2 QRA Input Data

The following activities comprise the determination of input data required for conducting the QRA

study:

Review of the project documents to determine process streams.

Identification of Loss of Containment (LOC) scenarios based on the hazardous properties of the

material.

Review of the design basis to obtain the properties of the stream (e.g. pressure, temperature,

composition and density); and

Calculation of the inventory released due to LOC events

3.3 Consequence Analysis

Consequence modeling will be conducted to evaluate the effect distances of the identified LOC

scenarios and their impact on people. The following activities comprise the consequence analyses

which will be carried out for the project:

Source term modelling to determine the release rate;

Physical effects modelling to determine the size of the hazard that is associated with the released

fluid (for example heat radiation, flammable liquid petroleum dispersion and toxic liquid

petroleum dispersion);

Comparison of the physical effects model with the impact criteria.

The consequence modeling will be performed using DNV PHAST 6.7 software.

3.4 Frequency Analysis

Once the potential release scenarios are identified, the next stage is to estimate the failure frequencies

(likelihood for the event to occur) based on international standard databases.

The frequency analysis will be performed as follows:

Identification of the base failure frequencies applicable to the liquid petroleum pipelines from the

relevant international standard databases;

The total failure frequencies will be derived from the base failure frequency data along with the

consideration of modification factors if applicable.

3.5 Risk Assessment

Risk assessment will be undertaken to evaluate the risk associated with the project facilities. The

consequence analysis results and failure frequencies will be combined using PHAST RISK 6.7 software.

The risk shall be typically presented as Location Specific Individual Risk (LSIR) contours overlaid on a

map and Individual Risk Per Annum (IRPA).

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3.6 Risk Evaluation

It involves the evaluation of the individual risk results against the UK HSE Risk Acceptance Criteria to

determine whether the risks are broadly acceptable, ALARP or unacceptable and to make some

professional judgments about the significance of the risks.

3.7 Risk Reduction Measures

Based on the risk evaluation, if the calculated risks fall in the unacceptable region, risk reduction

measures shall be implemented in order to reduce the risk to a tolerable or ALARP region. All

physically possible risk reduction measures shall be identified, which could be new measures or

improvements to existing measures already installed/ implemented. The risk evaluation after

implementation of recommendation/ risk reduction measures shall be carried out to demonstrate that

the risk shall be reduced to ALARP region and the study recommendations are adequate for the

project.

4. QRA ASSUMPTION SHEETS

The following assumptions are presented in the format of assumption sheets in the subsequent

section.

Assumption

No. Description

1. QRA Project Scope

2. Meteorological Conditions

3. Loss of Containment Scenarios

4. Material Composition, Process Conditions, Inventory & Discharge Coefficient

5. Software used

6. Release Size, Height, & Direction and Isolation time

7. Failure Frequency

8. Ignition Probability

9. Occupancy data & Population

10. Dyke area

11. Blocking factor

12. Impact criteria

13. Risk Acceptance Criteria

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Assumption 4.1 QRA Project Scope Assumption No. 1

iFluids Engineering scope of work is to perform a Quantitative Risk Assessment Study for the proposed

Bunkering facilities at Jawahar Dweep with the background as follows

Bunkering in Mumbai is currently being done at various jetties like Hay Bunder jetty, Mallet Bunder jetty

and old Pirpav, through tank trucks and barges. The pipeline supplies, though preferred, are currently

not feasible in most of the jetties except that at old Pirpav.

Typical Bunker supply parcel size ranges from 500 to 1500 MT. Handling of such huge quantity supplies

through existing Supply chain, i.e. Tank-trucks and Barges, involves intensive Operations / multiple

handling and thus poses Safety and Environmental concerns.

View above, Mumbai Port Trust (MbPT) mooted up a proposal to commission a single point for

Bunkering in Mumbai Port at MOT – Jawahar Dweep (Butcher Island) and decommission all existing

bunkering operation points (viz. Mallet Bunder, Old Pir-pau, Haybunder).

The proposal envisages facilitating barge berthing at jetty JD-2, and creation of facilities for Bunkering at

Butcher Island for seamless Bunkering operations through Pipe-line. Facilities will include Storage tanks,

input and discharge lines, pump-house etc. Details are as under:

TANKS: MbPT already has tanks in Butcher Island which are currently not in use and have

been offered to HPCL. All the tanks shall be cleaned, refurbished and put it to use for

storing of Class C bunker Fuels. Tanks proposed to be taken-over for bunkering

operations are 6 nos. with total proposed capacity of 36,600 KL.

The proposed Bunkering Terminal area is clearly earmarked for exclusive use by HPCL and

the dyke area of the Tanks, Pump House and Roads etc. is approx. 17225 sqmtr., which

will be taken on lease from MbPT for a period of 30 years. Entire land on Jawahar

Dweep (Butcher Island) belongs to MbPT.

JETTY: MbPT shall be providing HPCL permission to load Barges at modified Jetty, so that

bunker product shall be directly loaded in the Barge through dedicated pipe-lines and

through Flow-meters.

HPCL proposes to develop Bunkering Terminal by Refurbishing tanks, Pipe-line modifications, develop

Tank-farm area with proper PCC, Re-construct Dyke Wall, and Refurbish other allied facilities including

fire-fighting etc.

Accordingly, they have already signed Agreement with Mumbai Port Trust (MbPT) for taking-over of 6

nos. of Storage Tanks, Pump House and allied facilities for setting-up of Bunker Fuel Terminal. As per

Agreement, MbPT has also offered plot portion of the said Tank-Farm premises on long term lease (30

years) to HPCL.

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Assumption 4.1 QRA Project Scope Assumption No. 1

HPCL proposes Storage of Petroleum Products in 6 nos. Tanks as under:

HPCL have developed layout for Development of Bunkering Terminal, drawing enclosed herewith, so as

to achieve the purpose of “Receipt of products (FO-380, HF HSD) through MbPT pipeline, storage in 6

Nos. tanks and delivery of products (FO-380, HF HSD) for bunkering at JD-2”.

Products (i.e. FO-380 and HFHSD) shall be received through Mumbai Port Trust’s Black oil and White Oil

pipe-lines respectively, from the HPCL Mahul Refinery. Product may also be received through Pipe-line

from Vessels berthing at Jawahar Dweep/ Pirpau.

Normal pipe-line contents in these MBPT’s pipe-line are FO-180 and HSD respectively. Accordingly, it is

envisaged to designate one tank each for storage of pipe-line content of FO-180 and HSD. Post receipt

operations, this pipe-line content will be pushed-back to the pipe-line.

Delivery of the products (FO-380 and HFHSD) shall be primarily through MbPT Bunkering line in the

barges berthed at JD-2.

Reference:

1. Scope of Work

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Assumption 4.2 Meteorological Conditions Assumption No. 2

The following ambient conditions shall be used in the study: [Ref 1]

Average Ambient Temperature: 30°C

Average Relative Humidity: 75%

Solar Radiation: 1 kW/m2

The Pasquill Atmospheric Stability Classes [Ref 2]

Table 1: Pasquill Stability Class

Stability Class Definition

A Very Unstable

B Unstable

C Slightly Unstable

D Neutral

E Slightly Stable

F Stable

Based on the above figure, following stability/wind-speed categories shall be used in the study for two

weather conditions representing day and night:

F Stability, 2 m/s wind speed

D Stability, 5 m/s wind speed

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Assumption 4.2 Meteorological Conditions Assumption No. 2

Figure 2 Wind Rose Diagram- Jawahar Dweep

Surface Roughness

The ground characteristic shall be represented by surface roughness which is assumed as open flat

terrain & few isolated objects (30 mm).

Reference:

1. www.meteoblue.com-

LINK-https://www.meteoblue.com/en/weather/forecast/modelclimate/butcher-

island_india_1275027



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Assumption 4.3 Loss of Containment Scenarios Assumption No. 3

Isolatable section will be considered based on the shutdown valves (SDV) if available or the isolation/ block

valves. In conformance with industry standard methodology, Non-Return Valves (NRVs) or process control

valves are not considered to be an adequate or reliable form of isolation.

Note: 2” pipeline will not be considered for QRA modeling since it has negligible amount of inventory.

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Assumption 4.4 Material Composition, Process Conditions,

Inventory & Discharge Coefficient Assumption No. 4

Material Composition

The typical material composition for products handled shall be considered for the identified LOC

scenarios.

Components Composition

FO-180 N-TRICOSANE-100%

FO-380 N-TRICOSANE-100%

HSD

n-Decane- 2%

n-Undecane- 8%

n-Dodecane-12%

n-Tridecane-15%

n-Tetradecane-20%

n-Pentadecane-20%

n-Hexadecane-10%

n-Heptadecane-8%

n-Octadecane-5%

HFHSD

Note-

FO-180 & 380 will be considered as N-Tricosane which shall be the worst case scenario. Since the

difference between FO 180 & 380 is only viscosity, same composition will be considered.

Similarly for HSD & HFHSD, same composition will be considered for the assessment as a worst case

scenario.

Inventory

Inventory considered for each LOC scenarios is the sum of static inventory and dynamic inventory. The

static inventory is the holdup volume of materials within the pipeline.

The formula used for calculating the liquid petroleum inventory in the pipeline is (πD2Lρ)/4 kg. Where

D is pipeline diameter in meter and L is pipeline length in meter. The total pipeline inventory shall be

calculated based on the following information provided by Engineering team.

The dynamic inventory shall be calculated by considering 30 minutes for small leak and 10 minutes for

medium leak and 2minutes for large release of liquid petroleum from the above ground pipelines. 30

minutes will be considered for pin hole leaks and 10 minutes for medium and full bore rupture of

buried pipelines.

Reference:


2. Best Engineering practice.

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Assumption 4.5 Software Used Assumption No. 5

The following software shall be used for this QRA study:

PHAST 6.7

PHAST RISK 6.7

Reference:

https://www.dnvgl.com/services/hazard-analysis-phast-1675

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Assumption 4.6 Release Size, Height, Duration & Direction Assumption No. 6

Release Size

Table-2 presents the representative release sizes which shall be used for the LOC scenarios [Ref. 1].

Table 2: Representative Release Size for aboveground pipeline

Release Category Release Size, mm

Leak 10

Rupture Full bore

Release Height

The release height has been assumed to be at 1m from ground level.

Release Duration

The release duration will have a significant effect on the consequence modelling. In this study,

following release duration is considered.

Table 3 Isolation time

Release Category Isolation time, Seconds

Small Leak 1800

Large Leak 600

Rupture 120

Release Direction

The release direction shall be considered as horizontal for above ground pipeline/Tank release

scenarios.

Reference:

1. Guideline of Quantitative Risk Assessment - PGS 3 [Purple book].

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Assumption 4.7 Failure Frequency Assumption No. 7

The following tables represent the failure frequencies which shall be used in this study.

Table 4: Failure Frequency for aboveground Liquid petroleum Pipeline (per m per year)

Table 5 Failure Frequency for tanks

Note-For this project, the tanks are considered as single containment tanks.

Reference:

1. Guideline of Quantitative Risk Assessment - PGS 3 [Purple book].

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Assumption 4.8 Ignition Probability Assumption No. 9

The delayed ignition value, on the other hand, shall be calculated within PHAST Risk 6.7 and is unique

to each release case and release direction. The probability of delayed ignition depends on the strength,

location and presence factor of all ignition sources and the extent and duration of dispersing

flammable vapour clouds being exposed to those sources. Delayed ignition sources shall be modelled

as point, population, line and area sources.

The following ignition probabilities with respect to the ignition source for a time interval of one minute

shall be considered in this QRA study. (sources as applicable to the facility)

Table 6: Probability of ignition for a number of sources

Reference:

1. Guideline of Quantitative Risk Assessment - PGS 3 [Purple book]-Appendix 4.A

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Assumption 4.9 Occupancy Data & Population Assumption

No. 10

The occupancy data associated with the project are presented below:

Table 7: Occupancy data

Location of interest Population Fraction

Indoor*

Fraction

outdoor*

1. HPCL Tank area 10 0.80 0.20

2. BPCL area 30 0.90 0.10

3. Jetty Area (all

together) 80 0.85 0.15

4. Canteen 30 0.95 0.05

5. Pipeline manifold 20 0.90 0.10

Reference:-

1. Client input and best Engineering practice

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Assumption 4.10 Dyke Area Assumption

No. 10

The following Dyke (bund) area was considered during the risk assessment. These bunds are

considered that it will confine the leakages from the tanks.

Si. No Dyke

number

Tanks under

the Dyke

Effective

Area, m2

Enclosure

Capacity, KL

Net Height of

Dyke wall, m

1. DYKE-I Tanks-1, 2 7 6167 8050 1.8

2. DYKE-II Tanks-3, 4 3006 3490 1.4

3. DYKE-III Tank-8 2816 6920 2.8

Reference:-

1. Layout plan- HPCL/MOT-JD/LAY/001, Rev-0

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Assumption 4.11 Blocking factors Assumption

No. 11

The credit of the following modification factors will be considered for the frequency analysis since they

have the potential for risk reduction.

An automatic blocking system is a system where the detection of the leakage and closure of the

blocking valves is fully automatic. There is no action of an operator required.

- - The failure upon demand for the blocking system is 0.001 per demand.

A remote-controlled blocking system is a system where the detection of the leakage is fully

automatic. The detection results in a signal in the control room. The operator validates the signal

and closes the blocking valves using a switch in the control room.

- The failure upon demand for the blocking system is 0.01 per demand.

A hand-operated blocking system is a system where the detection of the leakage is fully automatic.

The detection results in a signal in the control room. The operator validates the signal, goes to the

location of the blocking valves and closes the valves by hand.

- The failure on demand for the blocking system is 0.01 per demand.

For this project, the blocking factor was considered as Manual

Reference:-

Guideline of Quantitative Risk Assessment - PGS 3 [Purple book].

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Assumption 4.12 Impact Criteria Assumption No. 12

The following impact criteria shall be used for the QRA study.

Flammable Liquid petroleum Dispersion

The impact distances shall be identified for the following concentrations:

100% LFL

Thermal Radiation Criteria

Table 8 :Thermal Radiation Criteria shows the impact criteria for Thermal Radiation.

Table 8 :Thermal Radiation Criteria

Radiation

Level Unit Impact

4* kW/m2 Indicative of personal injury after 30 seconds exposure

12.5* kW/m2 Indicative of 70% fatality

37.5* kW/m2 Indicative of 100% fatality

* All thermal radiation modelling shall include solar radiation (1 kW/m2) in the consequence

estimation.

Vapour cloud explosion Criteria

Table 9: Overpressure Criteria shows the impact criteria for Overpressure criteria.

Table 9: Overpressure Criteria

Overpressure

Level Unit Impact

0.01 Bar Shattering of glass

0.1 Bar Repairable damage to plant equipment & structure

0.3 Bar Major damage to plant equipment structure

Reference:


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Assumption 4.13 Risk Acceptance Criteria Assumption No. 13

Risk Acceptance Criteria for worker group shall be assessed from the Individual Risk Per Annum (IRPA)

value. The IRPA value shall be compared against the industry standard acceptance criteria as

presented in the UK HSE Risk Acceptance Criteria. The IRPA value shall primarily serve as the decision

making tool for worker group.

Table 10 Risk Criteria in Some Countries

AUTHORITY AND APPLICATION MAXIMUM

TOLERABLE RISK (PER YEAR)

NEGLIGIBLE RISK (PER YEAR)

VROM, The Netherlands (New) 1.0E-6 1.0E-8

VROM, The Netherlands (existing) 1.0E-5 1.0E-8

HSE, UK (existing-hazardous industry) 1.0E-4 1.0E-6

HSE, UK (New nuclear power station) 1.0E-5 1.0E-6

HSE, UK (Substance transport) 1.0E-4 1.0E-6

HSE, UK (New housing near plants) 3*1.0E-6 3*1.0E-7

Hong Kong Government (New plants) 1.0E-5 Not used

Figure 3 ALARP Principle

Reference:

1. UK HSE Risk Criteria

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5. LIST OF REFERENCE DOCUMENTS / STANDARDS


2. Methods for the determination of possible damage – CPR 16E [Green book]


4. UK HSE Risk Manual

5. P&ID- Black Oil system, White Oil system, Fire Protection system

6. Layout plan- HPCL/ MOT/-JD/LAY/001, rev-0

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