Liquefied Gas Handling Principles on Ships and in Terminals, (LGHP4) 4th Edition

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Published Date

July 2016

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Liquefied Gas Handling Principles on Ships and in Terminals, (LGHP4) 4th Edition

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This fully illustrated 500-page reference book covers every aspect of the safe handling of bulk liquid gases (LNG, LPG and chemical gases) on board ships and at the ship/shore interface at terminals. It is indispensable for personnel training for operational qualifications as well as those already engaged in liquefied gas operations.

The publication has been written primarily for serving ships’ officers and terminal staff who are responsible for cargo handling operations, but also for personnel who are about to be placed in positions of responsibility for these operations.  Its appeal extends also to many others, not directly involved in the operational aspects of the industry, who require a comprehensive and ready reference for technical aspects of their businesses. Liquefied Gas Handling Principles emphasises the importance of understanding the physical properties of gases in relation to the practical operation of gas-handling equipment on ships and at terminals.


In the sixteen years since this publication was last updated, the liquefied gas shipping and terminal industry has undergone considerable change. This revision reflects these changes which include, but are not limited to, vessel design, propulsion systems, size of fleet, floating regasification and reliquefaction, Arctic LNG, containment systems, efficiency increases in vessel operations, vessel capacities, technology, best practice and legislation.

Preface to the Fourth Edition
Prefaces to the Previous Editions
Figures and Tables
Key to Symbols

CHAPTER 1 Overview of the Carriage of Liquefied Gases by Sea



The Liquefied Gases


1.1.1 LNG production


1.1.2 LPG production


1.1.3 Chemical gases production


The Principal Products


Gas Carrier Fleet


Safety Record


Regulatory Framework


1.5.1 Safety of Life at Sea (SOLAS)


1.5.2 International Convention for the Prevention of Pollution From Ships, 1973, as modified by the Protocol of 1978 (MARPOL 73/78)


1.5.3 International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW)


1.5.4 Recommendations on the Safe Transport of Dangerous Cargoes and Related Activities in Port Areas


1.5.5 Ship certification



CHAPTER 2 Properties of Liquefied Gases

Chapter 2 Part a) The Chemistry of Liquefied Gases

    1. Atoms, Molecules and Chemical Bonds

      1. The hydrocarbon series

      2. Chemical formulae and the IUPAC naming system

      3. Saturated and unsaturated hydrocarbons 24

    2. The Chemical Gases 28

    3. Chemical Reactivity and Compatibility 31

      1. Reactivity with construction materials 31

      2. Reactivity with other cargoes 32

    4. Self-Reaction 33

      1. Reactive properties 33

      2. Formation of polymers or dimers 33

    5. Reaction with Water – Hydrate Formation 37

    6. Reaction with Air 39

      1. Combustion 39

      2. Flammability/flammable range 40

    7. Suppression of Flammability 44

      1. Inert gas and nitrogen 45

      2. The use of inert gas 46

      3. The chemical compatibility of cargoes with inert gas or nitrogen 47

Chapter 2 Part b) The Physics of Liquefied Gases 49

    1. The Physical Properties of Liquefied Gases and their States of Matter 49

      1. Temperature, heat energy and phase change 49

      2. Specific heat, enthalpy and entropy 50

      3. Phase change – a summary 51

      4. Saturated vapour pressure (SVP) 52

      5. Liquid and vapour densities 55

      6. Liquid to vapour volume ratios 55

      7. Spillage of cargo liquid 56

      8. Viscosity of liquid cargoes 57

Chapter 2 Part c) Gas Laws, Thermodynamic Principles and Reliquefaction 59

    1. The Gas Laws and Thermodynamic Principles 59

      1. Liquefied gas mixtures, their vapour pressures and compositions 62

      2. The ‘bubble point’ and ‘dew point’ of mixtures 64

      3. The laws of thermodynamics 66

      4. Enthalpy and Mollier charts 67

      5. Thermodynamic systems – isothermal, isentropic and adiabatic processes 70

      6. Heat transfer 71

      7. Practical examples of heat transfer 72

      8. Rollover 73

    2. Reliquefaction 75


Indirect cycle



Direct cycle



Cascade cycle



LNG reliquefaction cycles





Liquefied Gas Carrier Types




Chapter 3 Part a) Gas Carrier Types




3.1 Design Standards and Ship Types



3.1.1 The IGC Code



3.1.2 Factors affecting gas carrier design



3.2 Gas Carrier Types



3.2.1 Fully-pressurised ships



3.2.2 Semi-refrigerated ships



3.2.3 Fully-refrigerated ships



3.2.4 Ethylene/ethane ships



3.2.5 LNG carriers



3.2.6 Regasification vessels (RVs)



3.3 Gas Carrier Layout



3.4 Hazardous Zones



3.4.1 Hazardous area classification



3.4.2 IEC definitions



3.4.3 Zone determination



3.4.4 Ventilation



3.5 Survival Capability



3.6 Surveys and Certification



3.6.1 Certificate of fitness



3.6.2 Carriage of noxious liquid substances (NLS)


The purpose of SIGTTO is to promote shipping and terminal operations for liquefied gases which are safe, environmentally respo

Title: Liquefied Gas Handling Principles on Ships and in Terminals, (LGHP4) 4th Edition
Edition: Fourth
Number of Pages: 568
Product Code: WS1454K
ISBN: ISBN 13: 978-1-85609-714-7 (9781856097147), ISBN 10: 1-85609-714-5 (1856097145)
Published Date: July 2016
Binding Format: Hardback
Book Height: 304 mm
Book Width: 215 mm
Book Spine: 40 mm
Weight: 2.50 kg
Author: SIGTTO

Customer Reviews

Everything you need to know about handling liquefied gas cargoes on board ship and at the terminal ship-shore interface Review by LNG World Shipping 1st September 2016
SIGTTO Updates LNG/LPG guide
Everything you need to know about handling liquefied gas cargoes on board ship and at the terminal ship-shore interface can be found between the covers of the updated fourth edition of Liquefied Gas Handling Principles, flagship publication of the Society of International Gas Tanker and Terminal Operators (SIGTTO).

The guide has come a long way since its 160-page first edition launched in 1986 and the previous, 275-page third edition, published in 2000. The latest edition of the book, nicknamed LGHP4 by the SIGTTO community, has been revised to accommodate the many advances taking place in gas shipping and terminal technology and now weighs in at 530 pages and 2.5kg.

Liquefied Gas Handling Principles deals with handling liquefied gases carried in bulk, including LNG, LPG and chemical gases, and is a valuable reference work for everyone involved in design, construction and operation of gas carriers and terminals.

Like previous publications in the series, however, the new edition has been written primarily for serving ships’ officers and terminal staff responsible for cargo-handling operations, and for those who oversee these operations.

SIGTTO now has 139 full members, 48 associates and 27 non-contributory members. It drew on this broad resource base to compile LGHP4. The job of editing and structuring that input into the latest revisions fell to SIGTTO technical adviser Rick Boudiette, who submitted the final draft for peer review and endorsement by members of SIGTTO’s General Purposes Committee and several subject-matter experts.

The guide stresses the importance of understanding the physical properties of liquefied gas cargoes in relation to the operation of gas-handling equipment and systems on the ship and at loading and discharge jetties. Operators need to know how and why each gas behaves the way it does, and the associated hazards, across a range of operating scenarios, to appreciate the role of the shipboard and terminal equipment they are controlling.

LGHP4 features a revised and extended section on liquefied gas properties. Chapter two has been divided into three major subsections; the chemistry of liquefied gases, the physics of liquefied gases and gas laws, thermodynamic principles and reliquefaction.

For a newcomer there is much vital information to assimilate. A modern multigas carrier is constructed to carry upwards of 15 different cargoes, each with its own flash point, flammability range, auto-ignition temperature, boiling point, critical pressure, reactivity characteristics, density, viscosity and chemical compatibility with inert gas.

Once these properties are assimilated, it is necessary to understand the concepts of specific heat, enthalpy, entropy, phase change and saturated vapour pressure, and the basic laws of thermodynamics.

Safe and efficient handling of cargoes – and adhering to procedures that mitigate against the risks posed by their carriage in bulk – requires a basic appreciation of these liquefied gas properties and principles of gas behaviour.


LGHP4 may weigh heavily on the scales, but it brings a light touch to the complexities of handling liquefied gases and is above all a reader-friendly publication. The running commentary, with its straightforward explanations and numerous section breaks, incorporates colour-coded blocks of text.

Blue-shaded boxes contain information of an operational nature that offers useful hints for planning purposes. Yellow-shaded boxes contain cautionary information regarding operations. Grey-shaded boxes with a red border denote information considered to be of particular importance. These cautions are relatively rare and merit special attention.

One blue-tinted box contains LGHP4’s statement that certain chemical gases such as diethyl ether, propylene oxide and isoprene, which are not strictly liquefied gases, are carried under high vapour pressures. This fact, coupled with the health and flammability hazards, has led to these and similar compounds being listed in both the International Gas Carrier (IGC) and International Bulk Chemical (IBC) Codes.

These cargoes are most often shipped in gas carriers but when carried on chemical tankers, such cargoes will often be required to be stowed in independent tanks. They are also subject to many of the handling principles covered in LGHP4.

Readers will find the visual material in LGHP4 invaluable. Most of the book’s 325-plus figures are new or are updated versions of earlier visuals. Rick Boudiette and staff at Witherby developed the figures that required amendment or configuration from scratch.

The figures range from flow, equilibrium, schematic and process diagrams and depictions of refrigeration and reliquefaction cycles to photos of gas ship types, cutaways of containment systems and key cargo-handling equipment, propulsion system overviews and pictures of ship and terminal safety systems and damage that can be caused by unwanted reactions such as polymerisation and hydrate formation.

The figures are augmented by detailed tables, including those that encapsulate the key physical and chemical property data of the many gas carrier cargoes.

Technical advances

Notwithstanding the expanded coverage of liquefied gas physical and chemical properties, the increased LGHP4 page count reflects technological advances during the 16 years since the third edition appeared. And so offshore operations, a range of new propulsion systems and environmental stewardship get the LGHP treatment for the first time.

Ship-to-ship (STS) cargo transfers have become a routine commercial operation over the past decade, thanks to the rising popularity of floating storage and regasification units
(FSRUs) as LNG-receiving terminals. And as the first floating LNG production (FLNG) vessels come into service, similar transfers will become part of the operating scenario at offshore loading facilities, prompting LGHP to review the various STS systems available.

Considerations of propulsion systems and environmental stewardship cross over, as the need to meet new, mandated standards of higher energy efficiency benefits from the introduction of dual-fuel, gas-burning engines. Two-stroke engines offer the highest propulsive efficiencies of marine power plants and manufacturers have succeeded in developing dual-fuel versions of these units and, over the past 18 months, in winning the majority of LNG carrier newbuilding propulsion system orders.

Technical innovation has also manifested itself in other, more subtle ways across the gas cargo-handling spectrum. New two and four-stroke dual-fuel engines have required new types of equipment to be fitted on board LNG carriers, including gas combustion units (GCUs), reliquefaction plants and other systems for controlling boil-off gas (BOG).

LGHP4 also considers the differences between warm and cold ballast voyages, highlighting the key role of GCUs for the former and reliquefaction plants for the latter.

In the cargo containment-system section the new edition reviews the refinements that Gaztransport & Technigaz (GTT) has introduced in recent years with its No 96 and Mark III membranes, spurred by the drive to reduce cargo BOG rates and to enhance membranes’ ability to withstand sloshing loads.

For the Mark III membrane these goals have been achieved through the development of Mark III Flex. In the case of the No 96 design, using different insulating materials provides lower BOG rates and strengthened insulation boxes increase the ability to sustain higher sloshing loads without system damage.

The fourth edition of Liquefied Gas Handling Principles is available from Witherby Publishing;, priced £275
(Posted on 09/09/2016)

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