guideline for installing rov systems on vessels or platforms

8/12/2019 Guideline for Installing ROV systems on vessels or platforms

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Guidelines forInstalling ROV Systems onVessels or Platforms


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Guidelines for Installing ROV Systems on Vessels or Platforms

IMCA R 018 May 2013

1 Introduction ........................................................................................................... 1

2 Glossary of Terms and Definitions ...................................................................... 2

3 ROV Classification ................................................................................................. 3

3.1 Class I Observation ROV ................................................................................................................................. 3 3.2 Class II Observation ROV with Payload Option ........................................................................................ 3

3.3 Class III Work Class ROV ................................................................................................................................ 3 3.4 Class IV Towed and Bottom-crawling Vehicles .......................................................................................... 3 3.5 Class V Prototype or Development Vehicles .............................................................................................. 3

4 ROV System Layout .............................................................................................. 4

4.1 General ..................................................................................................................................................................... 4 4.2 ROV Deployment Method ............... ................ ................ ................ ................ ................ ................ ................ .... 4 4.3 Launch and Recovery System (LARS) ............................................................................................................... 5

4.4 Umbilical Winch ................ ................ ................ ................ ................ ................. ................ ................ ................ .... 5 4.5 A-frame/Handling System .............. ................ ................ ................ ................ ................. ................ ................ ...... 5 4.6 Hydraulic Power Unit............................................................................................................................................ 6 4.7 ROV Control Room/Cabin .............. ................ ................ ................ ................ ................ ................ ................ .... 6 4.8 Stores ........................................................................................................................................................................ 6 4.9 Workshop ................................................................................................................................................................ 6 4.10 Deck Space ............... ................ ................ ................. ................ ................ ................ ................ ................ ............... 6

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1 Introduction

The purpose of this document is to provide guidance on the installation of a remotely operated vehicle (ROV)System, or Systems, on to vessels and/or platforms. It is not intended to be a definitive guideline; instead it isintended to assist vessel and platform owners to understand the outline requirements of installing andmobilising an ROV System, i.e. to highlight some of the questions that may need to be asked. It can also beutilised in discussions with ship and platform owners, designers and fabricators/builders when buildspecifications are being prepared.

There are wide variations in the complexity and requirements of ROV Systems, ranging as they do from smallobservation class ROV Systems weighing perhaps 10 tons, through to large and complex trenching ROVSystems which might weigh hundreds of tons. Therefore it is important to discuss ROV installation issues withall the relevant stakeholders at the earliest opportunity.

In the context of this guidance document, the term ROV System is used to define the ROV and all of itsrequired equipment such as the launch and recovery system (LARS), the tether management system (TMS), thecontrol cabin, the workshop cabin, the umbilical winch as well as the ROV (the vehicle) itself. Where thelowercase system is used in this document, this refers to the sub element of the ROV System, e.g. thehydraulic system or electrical system, etc.

Whilst the main body of this document describes the issues that may arise during the installation for a workclass ROV System on to a vessel or platform, the principles outlined are applicable to all classes and variants of

ROV.

The guidance is intended for use by:

vessel and platform owner/operators; vessel and platform designers; ROV contractor representatives; client and contractor staff who prepare bid documents and contracts;

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2 Glossary of Terms and Definitions

For the purpose of this document the following terms may apply:

AUV Autonomous underwater vehicle

ATEX Directive on equipment and protective systems intended for use in potentiallyexplosive atmospheres (ATEX Appareils destins tre utiliss en AtmosphresExplosives)

CCTV Closed-circuit television

Client Company or organisation for which the work is being carried out

DP Dynamic positioningDSV Diving support vessel

GA General arrangement

HP High pressure

HPU Hydraulic power unit

HUET Helicopter and underwater escape training

ISO International Organization for Standardization

LARS Launch and recovery system

LIM Line insulation monitor

MA set Motor/alternator set

MODU Mobile offshore drilling unit

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3 ROV Classification

The term remotely operated vehicle (ROV) covers a wide range of equipment and no single ROV System canbe described as typical. Not only are there numerous ROV designs and classifications, but the same basicROV tractor can be modified to carry out a wide range of different tasks. Within this guidance, however,ROV Systems are considered to be unmanned vehicles (rather than manned submersibles which are subject toseparate requirements).

The following is based upon IMCA R 004 Code of practice for the safe and efficient operation of remotely operatedvehicles and provides a brief description of the high level classification of ROV Systems in use today.

3.1 Class I Observation ROV

These ROV Systems have a small, compact vehicle, which can be fitted with camera/lights and sonaronly. They are primarily intended for pure observation, although they may be able to handle oneadditional sensor (such as cathodic protection (CP) equipment), as well as an additional video or stillscamera.

3.2 Class II Observation ROV with Payload Option

These ROV Systems have vehicles that are fitted with two simultaneously viewable cameras and asonar as standard and are capable of handling additional sensors as payload. They may also have abasic manipulative (grabber) capability. They should be able to operate without loss of originalfunction while carrying two additional sensors/manipulators.

3.3 Class III Work Class ROV

These ROV Systems have vehicles large enough to carry extra sensors and/or manipulators as amatter of course without loss of functionality. Class III vehicles commonly have a multiplexing

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4 ROV System Layout

4.1 General

An ROV System generally encompasses the ROV itself and the ROV deployment system or launch andrecovery system (LARS), the ROV control room/cabin, and ROV umbilical.

Deck space for the total ROV System needs careful consideration, as not only is space needed for theROV itself but space is needed for the stores, maintenance workshop, tool and skid handlingrequirements as well the ROV control room, the deployment system to be used and, if appropriate,the tether management system.

Issues regarding the ROV System layout are discussed below. A pre-mobilisation site visit will behelpful in determining the System location.

4.2 ROV Deployment Method

There are two general methods of deploying and recovering an ROV. Operational considerations andthe location of the installation on the vessel or platform will determine which method is used.

Care should be taken to minimise the interference the launch and recovery of the ROV and itsancillary equipment has on other vessel/platform operations. Vessel or platform GA (generalarrangement) drawings should be consulted prior to the installation of any ROV System, to assist withdetermining the optimum location(s).

4.2.1 Over the Side Deployment

This type of deployment is cost-effective and frequently used, both for launching stand-aloneROVs from vessels of opportunity and as a permanently installed handling system on an ROVsupport vessel (ROVSV). An A-frame lifts and luffs outboard the ROV, generally with a

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Figure 2 An ROV descending into a moonpool

4.3 Launch and Recovery System (LARS)

The ROV LARS should be located such that there are no obstructions below or immediately adjacentto the launch and recovery site which might restrict or impede operations.

On vessels with dynamic positioning or multiple thruster systems, care should be taken to minimisethe risk of umbilicals and/or vehicles coming into conflict with such thrusters, if necessary ensuringthat the thrusters are isolated during launch and recovery of the vehicle.

When ROVs are installed on platforms, particular consideration should be given to the location of thefollowing:

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4.6 Hydraulic Power Unit

When locating the hydraulic power unit (HPU), the following should be taken into account:

Positioning of exhausts and vents such that they remain clear and are not located where theycould pose a risk to personnel;

Routing of electrical power and hydraulic hoses to and from the HPU.

4.7 ROV Control Room/Cabin

The ROV is operated, or piloted, from the ROV control room, or cabin. ROV control rooms can bebuilt into ISO standard (dimension) freight containers, or form part of the permanent installation on a

vessel or platform. As the ROV operators will be spending a great deal of time in the control room, itis very important that adequate welfare facilities are provided and the room is as comfortable aspossible. It should be noted that whilst the dimensions may conform to ISO standard freightcontainers, the reality is that units are extremely specialist and subject to various international rulesand regulations.

Where the controls are housed within a control room that is part of the platform or vessel,consideration should be given to the electrical and electronic equipment situated within the ROVcontrol room. Air conditioning for cooling purposes will be necessary as the topside equipment of

most ROV systems will generate significant heat; any other environmental constraints in the siting ofthe ROV control room should also be taken into account.

4.8 Stores

An ROV installation will require an area for storage of spare parts and consumables. The arearequired may vary in size depending on the size, type and class of the ROV and the operation forwhich it is being used. ISO standard freight containers are commonly used, but once again they aresubject to various international rules and regulations.


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Figure 3 An ROV and TMS being maintained

4.11 Headroom

Care should be taken to ensure that appropriate overhead clearance is available for ROV operations,i l di h f ll i


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5 ROV System Services

5.1 Power Requirements

A typical class III work class ROV System requires a 380-480VAC, 60Hz supply, although manymodern ROV Systems can cope with a wider variation of incoming supply voltage. Where the vesselor platform has a higher supply voltage, installation of suitable step-down isolation transformers will berequired to convert the host supply voltage to a lower voltage usable by the ROV system. Thecomplex nature of an ROV, with sensitive electronics, survey and video equipment; working alongsidemotors and pumps, can impose limitations on its ability to cope with a poor quality electrical supply.Additionally, the length of the umbilical and the tether will have an effect on the supply voltage at theROV. For this reason, the ROV System power distribution unit (PDU) is normally fitted with various

tappings that can adjust the output voltage at the ROV and/or TMS.

Motors and hydraulic pumps on the ROV handling system may be able to cope with instability in thehost power supply; whereas the ROV control room instrument systems and the ROV itself may beadversely affected.

If the vessel or platform power supply is sufficient in quality and frequency stability, and can providesufficient current, it may be possible to power the ROV control room instruments directly from theelectrical distribution switchboard of the vessel or platform. Alternatively a separate power source

may be required.

5.1.1 Power Supply Quality

The following technical issues affecting power supply should be considered:

Voltage fluctuations for steady load conditions the voltage at the bus bars of themain switchboard should be within 97.5% and 102.5% of the nominal system voltage.For transient conditions these values should be in the order of +20% and -15%, with arecovery time not exceeding 1.5 seconds;


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ROV power distribution onboard a 50Hz vessel is a special case. Some of the factors thatshould be taken into account are as follows:

Available deck space to host alternative supply options;

Design of MA set, motor rating, alternator rating, containerisation; Availability of a suitable supply for an MA set;

The number and complexity of ROV systems onboard; The requirement for a backup supply, changeover switches, etc.;

Any requirements for additional distribution panels.

It is important when using a diesel generator or MA set that the output supply is provided

with earth leakage protection. This can be in the form of a line insulation monitor (LIM) or aresidual current device (RCD) and core balance transformer. An insulation fault should beindicated by an audible and visual alarm either in the ROV control room, vessel bridge orplatform control room.

Not all vessels have 440/480VAC supplies. It is important to ensure that the supply voltage iscompatible with the voltage range of the ROV system. If not, the following alternativetechniques may be considered:

Full system power motor/alternator (MA) set;

Full system power diesel generator; Replace motors and transformers with others having the correct voltage rating.

Any diesel-driven generators should be appropriately certified as safe for use in the vessel orplatform environment. Additionally, care should be taken to establish where the diesel supplyis located, and to ensure, as far as possible, that fuel is moved from the main supply to thegenerator tank via a suitable isolation valve.

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5.4 Low Pressure Air Services

On a typical vessel or platform installation low pressure (general purpose) air (max. 7 bar) is madeavailable for general purpose air driven tooling. More specialised pneumatic equipment used on anROV system may have different requirements in terms of external air supply, which would need to beconsidered on a case by case basis.

5.5 Fresh Water

Fresh water supplies should be provided close to the ROV landing point for the purpose of washingdown after use this is a feature of the planned preventative maintenance (PPM) arrangements formost ROV systems.

5.6 Seawater Cooling

Some equipment on an ROV may require seawater cooling, for example the heat exchanger on ahydraulic power unit (HPU). Care should be taken to check the specification of equipment requiring aseawater supply.

5.7 Fire Alarm Integration

Where possible any outside working areas should be connected to the vessel/platform fire alarmsystem, including audio and visual warnings taking account of the typical high ambient noise when theROV handling system is in use.

5.8 CCTV

Closed circuit TV cameras (CCTV) are generally employed to provide a remote view of the

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6 Operational Requirements

There are a number of operational issues which need consideration when selecting the location of an ROVSystem on a vessel or platform, including:

Sea state; Load path and deck loading; Regulation and classification.

6.1 Sea State

Sea state is generally described in terms of the significant wave height (Hs) in metres and thecorresponding wave period (Tp) in seconds. Sea state operating requirements may range from asignificant wave height (Hs) of 2.5m up to a Hs of 6.0m depending on the client, operating location andthe type and size of vessel.

These Hs/Tp parameters can also be linked to the Beaufort Scale. Traditionally the Beaufort Scale seastate 6 has been used as a maximum permissible sea state for ROV systems. This sea state is usuallydefined by a significant wave height of Hs 4.25m and wave period of 8-10s. Launch and recovery ofthe ROV in a full sea state 6 could impart loadings of up to 2g on the ROV load path.

In addition to the wave height and period, the safe deployment and recovery of an ROV will alsodepend on several other interrelated factors, including but not limited to:

vessel heading; wind speed; wave direction and interaction; surface currents; visibility;


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Once the location of the ROV System onboard the vessel or platform has been established and themaximum operating weather conditions have been agreed, the operational dynamic loads for theSystem can then be calculated.

The ROV supplier can then check that the entire load path of the ROV System is rated for thedynamic loadings. The attachment method to the deck and the supporting deck structure should alsobe checked for the above loadings by the vessel naval architect.

6.3 Regulation and Classification

All structural and engineering design of an ROV handling system should have been carried out inaccordance with recognised rules, regulations, codes and standards; irrespective of its final location for

deployment. Where the vessel/platform owner specifies that the ROV handling system should be incompliance with the rules, regulations, codes and standards of a given classification society, then thatsocietys rules, regulations, codes and standards should prevail. It should be noted that ROV handlingsystems are not normally built under conditions of class; however there are classification societydocuments which can be useful when designing such systems. Such documents include:

Lloyds Register; Code for Lifting Appliances in a Marine Environment; Lloyds Register of Shipping; Rules for Diving Systems; DNV Offshore Standard for Diving Systems (DNV-Os-E402); DNV Standard for Certification No 2.22 Lifting Appliances.


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7 References

IMCA R 004 Code of practice for the safe and efficient operation of remotely operated vehicles

IMCA S 016 Mobilisation checklist for offshore survey operations
http://www.imca-int.com/media/72417/imcar004.pdfhttp://www.imca-int.com/media/72417/imcar004.pdfhttp://www.imca-int.com/media/70551/imcas016.pdfhttp://www.imca-int.com/media/70551/imcas016.pdfhttp://www.imca-int.com/media/70551/imcas016.pdfhttp://www.imca-int.com/media/72417/imcar004.pdf


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I M CA R

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Appendix 1

Suggested ROV System Checklist

DescriptionMeasurementUnit

Reference toSection in thisDocument ROV Contractor Information Vessel Owner Requirements

Section 4 ROV System Layout

ROV Deployment MethodOver the side deployment specific detailsMoonpool/cursor deployment specific details

4.2

ROV (Including any TMS requirements)IMCA Class Manufacturer/TypeDimensions Length, Width, HeightWeight

Power supply requirements

mKg

KVA

3

4.1Umbilical WinchManufacturer/TypeDimensions Length, Width, HeightWeightPower supply requirements

mKgKVA

4.4

4.1

Handling System Control StationsManufacturer/TypeDimensions Length, Width, HeightWeightPower supply requirements

mKgKVA

4.14

4.1

Hydraulic Power UnitManufacturer/TypeDimensions Length, Width, HeightWeightPower supply requirements

mKgKVA

4.6

4.1


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I M CA R

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DescriptionMeasurementUnit

Reference toSection in thisDocument ROV Contractor Information Vessel Owner Requirements

ROV Control Room/CabinManufacturer/TypeDimensions Length, Width, HeightWeightPower supply requirements

mKgKVA

4.7

4.1

StoresManufacturer/TypeDimensions Length, Width, HeightWeightPower supply requirements

mKgKVA

4.8

4.1

WorkshopManufacturer/TypeDimensions Length, Width, Height

WeightPower supply requirements

m

KgKVA

4.9

Water Drainage and Oil ReclamationManufacturer/TypeDimensions Length, Width, HeightWeightPower supply requirements

mKgKVA

4.13

Section 6 Operational Requirements

Sea StateSignificant wave heightWave period

HsTp

6.1

Load Path and Deck LoadingVessel Response Amplitude Operators (RAO)Engineering design Certifying Authority

6.24.3

Table 1 Suggested checklist to gather ROV System specific information for use in discussions between vessel owner and ROV contractor

guideline for installing rov systems on vessels or platforms

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