Tanker Safety Guide: Liquefied Gas (eBook)

Published Date

June 2020

Tanker Safety Guide: Liquefied Gas (eBook)

(Excludes any applicable taxes)

This is the definitive industry best practice guide for gas carrier operators. It is a carriage requirement under the national regulations of many flag States and it is recommended that a copy is carried on board every ship engaged in the transportation of liquefied gas by sea.

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This publication provides practical guidance on every aspect of liquefied gas operations and transportation. It identifies the properties and hazards of liquefied gases and the necessary precautions and safety systems. Detailed information is provided on cargo handling operations and equipment. It also discusses enclosed space entry, emergency planning and firefighting.


The Appendices contain cargo data sheets, information on reliquefaction and boil-off control, details of cargo handling systems and equipment, the ship/shore safety checklist and sample documentation.

Chapter 1 – The Properties and Hazards of Liquefied Gases
1.1    Introduction
1.2    Flammability
1.3    Occupational Health Hazards
1.4    Reactivity
1.5    Corrosivity
1.6    Vapour Characteristics
1.7    Low Temperature Effects
1.8    Pressure


Chapter 2 – General Precautions
2.1    Introduction
2.2    Cargo Information
2.3    Mooring
2.4    Emergency Towing-Off Pennants
2.5    Access to Ship
2.6    Warning Notices
2.7    Craft Alongside
2.8    Weather Precautions
2.9    Openings in Deckhouses and Superstructures
2.10  Machinery Spaces
2.11  Cargo Machinery Room
2.12  Ship’s Readiness to Move
2.13  Navigation and Bridge Procedures
2.14  Environmental Protection
2.15  Firefighting and Fire Protection
2.16  Helicopter Operations

Chapter 3 – Safety Management
3.1    Introduction
3.2    Safety Culture
3.3    The ISM Code
3.4    Company Responsibility
3.5    Safety Information for Shore Personnel
3.6    Outside Contractors
3.7    Risk Management
3.8    Safe Operations
3.9    Incident Investigations
3.10  Ship’s Manning
3.11  Personal Protection and Lifesaving

Chapter 4 – Transportation of Liquefied Gas
4.1    Introduction
4.2    Basic Cargo System Design Considerations
4.3    The IGC Code
4.4    Cargo Containment Systems
4.5    Gas Tanker Types and Arrangements
4.6    Carriage of Noxious Liquid Substances
4.7    MARPOL
4.8    IMO Ballast Water Management Convention


Chapter 5 – Fire Hazards and Precautions
5.1    Introduction
5.2    Flammability of Liquefied Gases
5.3    Cargo Vapour Generation and Disposal
5.4    Atmosphere Control
5.5    Static Electricity
5.6    Precautions Against Sources of Ignition
5.7    Hot Work
5.8    Cold Work
5.9    Firefighting and Fire Protection Equipment


Chapter 6 – Cargo Operations
6.1    Introduction

6.2    Responsibility
6.3    Commissioning the Cargo System
6.4    General Cycle of Operations
6.5    Preparation for Cargo Transfer
6.6    Inerting and Gassing-Up
6.7    Preparations for Loading
6.8    Cargo Loading
6.9    Cargo Conditioning
6.10  Cargo Discharge
6.11  Ship-to-Ship Transfer
6.12  Ballasting and De-Ballasting
6.13  Separation of Cargoes
6.14  Commingling of LPG Cargoes in Port
6.15  Changing Cargoes
6.16  Gas-Freeing and Aeration
6.17  Venting at Sea
6.18  Deck Storage Tanks
6.19  Sampling
6.20  Custody Transfer Measurement Systems
6.21  Drydocking and Repair Periods


Chapter 7 – Cargo Equipment
7.1    Introduction
7.2    Plant and Equipment Precautions
7.3    Equipment Maintenance


Chapter 8 – Enclosed Spaces
8.1    General
8.2    Atmosphere in Enclosed Spaces
8.3    Requirements for Enclosed Space Entry
8.4    Testing Before Entry
8.5    Entry into Enclosed Spaces
8.6    Work in Enclosed Spaces
8.7    Rescue from Enclosed Spaces


Chapter 9 – Emergency Planning
9.1    Introduction
9.2    Pre-Planning
9.3    Emergencies


Chapter 10 – Firefighting
10.1  Introduction
10.2  Firefighting Organisation
10.3  Special Considerations for Fighting Liquefied Gas Fires
10.4  Vent Mast Fires
10.5  Fires Near to the Ship
10.6  BLEVE




Appendix 1 – Cargo Data Sheets

Appendix 2 – Reliquefaction and Boil-Off Control

Appendix 3 – Cargo Handling Plant and Equipment

Appendix 4 – Cargo System Instrumentation

Appendix 5 – Drydocking and Repair Periods

Appendix 6 – Basic Thermodynamic Theory

Appendix 7 – Pressure Surge Effects

Appendix 8 – Ship/Shore Safety Checklist

Appendix 9 – Liquefied Gas Cargo Information Form

Appendix 10 – Example Personal Protective Equipment Matrix

Appendix 11 – Inhibited Cargo Certificate

Appendix 12 – Example Hot Work Permit

Appendix 13 – Example Enclosed Space Entry Permit

Appendix 14 – Liquefied Gas Cargo Hose Form

Appendix 15 – Conversion Tables



The purpose of the Tanker Safety Guide (Liquefied Gas) is to provide up-to-date information on recognised industry best practices for the guidance of personnel serving on ships carrying liquefied gases in bulk. The information in this Guide serves to reinforce the provisions of the latest version of the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code), developed and published by the International Maritime Organization (IMO).


This third edition of the Guide, which was first published in 1978, takes into account the latest developments in management philosophy, design and operations. These include regulatory issues, such as the implementation of the International Safety Management (ISM) Code and the International Ship and Port Facility Security (ISPS) Code, and operational practices such as the reliquefaction of LNG and developments regarding emergency shutdown (ESD) practices. The Guide is intended to be a companion to the Tanker Safety Guide (Chemicals) published by ICS.


The Guide deals primarily with operational matters and good safety practices. It does not include recommendations on the construction or maintenance of gas tankers or their equipment as such standards are set by IMO, national administrations and classification societies. Likewise, the Guide does not address the operation of specific items of equipment or their maintenance and repair, although in some cases broad references are made to these matters. Nor does the Guide address commercial matters such as tank preparation, cargo quality or equipment performance standards as these are set by industrial practices and the requirements of liquefied gas cargo owners.


The cargo data sheets contained in Appendix 1 of the Guide outline the requirements for the safe handling and carriage of liquefied gas cargoes, refrigerants and anti-freeze additives commonly used on gas tankers. Each cargo data sheet includes details of the physical and chemical properties of the cargo, the hazards it presents, and the action to be taken in the event of an emergency.


For the purpose of promoting consistent and uniform safe operational practices it is recommended that a copy of this Guide is available on board all gas tankers. It is also recommended that a copy of the latest edition of the International Safety Guide for Oil Tankers and Terminals (ISGOTT) (ICS, OCIMF and IAPH) is also provided on board as a significant part of the content is relevant to gas tankers.


It is emphasised that this Guide is intended to complement, not supersede, any company safety and operational guidelines or ship emergency plans, including safety procedures contained in an approved Safety Management System required by the ISM Code. It should also be borne in mind that in all cases the advice given may be subject to local or national regulations, and that terminal operators have their own safety procedures which could affect cargo handling operations and the measures to be adopted in emergencies. The Master and all personnel should be aware of and comply with those regulations and procedures. Their existence will be highlighted by the use of the Ship/Shore Safety Checklist included in Appendix 8 of this Guide which, together with its guidelines for completion, remains a fundamental part of establishing safe conditions for the transport and handling of liquefied gases.


The International Chamber of Shipping (ICS) is the principal international trade association for the shipping industry, representing shipowners and operators in all sectors and trades.

ICS membership comprises national shipowners’ associations in Asia, Europe and the Americas whose member shipping companies operate over 80% of the world’s merchant tonnage.

Established in 1921, ICS is concerned with all technical, legal, employment affairs and policy issues that may affect international shipping.

ICS represents shipowners with the various intergovernmental regulatory bodies that impact on shipping, including the International Maritime Organization.

ICS also develops best practices and guidance, including a wide range of publications and free resources that are used by ship operators globally.


Title: Tanker Safety Guide: Liquefied Gas (eBook)
Edition: Third
Product Code: MA1011EA
ISBN: 978-1-8380784-9-2
Published Date: June 2020
Author: ICS

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