This book provides an explanation of the SIGTTO LNG Shipping Competency Standards, which have previously been unavailable within the public domain or unsatisfactorily verified and credited. Technical expertise has been sought from numerous sources, ensuring that there is no equipment or company bias within.
The shipment of LNG has grown steadily since 1958 when the first ship to carry LNG, the ‘Methane Pioneer’, carried 5,000 m3 of LNG from the USA to the UK. By mid 2006 the world fleet of LNG Carriers had grown to over 200 ships in service. By early 2009 this figure was over 300 and during 2011 the number of LNG Carriers operating worldwide will exceed 400.
LNG Shipping possesses the most envied safety record in world shipping, with no significant accident or cargo spillage in its first 40 years spanning more than 40,000 sea voyages. However, with a lack of training berths on the existing tonnage and new operations evolving in countries with no LNG experience the industry must work hard to retain that position.
The introduction of a system of internationally recognised and structured training programs was necessary and, in November 2005, SIGTTO went a long way to fulfilling that requirement by releasing the 1st version of its LNG Shipping Competency Standards to provide guidance and suggested best practice for the industry. These standards were reviewed and accepted by an IMO sub-committee in the spring of 2006 and published by SIGTTO shortly afterwards with a 2nd edition being published in December 2008.
The LNG Shipping Competency Standards summarized the tasks and knowledge considered necessary to perform in the industry, broken down by rank. ‘LNG Shipping Knowledge’, closely follows that format, providing the actual underpinning knowledge that is asked for in each instance.
This makes it a powerful set of supporting documents to the ‘LNG Shipping Competency Standards’, providing and filling in information that is either not available within the public domain or that is available but unsatisfactorily verified and credited.During the course of the construction of this publication, technical expertise has been sought from many and varied sources, ensuring that there is no equipment or company bias within.
1 Fundamental Knowledge and Understanding .
1.1 Physics and Chemistry .
1.1.1 Have an Awareness of the Physics Relating to the Change of State of Fluids .
1.1.4 Know and Understand the Principles Involved in the Changing of Tank Atmospheres .
1.1.6 The Meaning of `Dew Point'.
1.2.1 Have an Awareness of Main Design Principles .
1.2.2 Know and Understand the Main Design Principles .
1.3 Regulations and Guidance .
1.3.1 Have an Awareness of the Applicable Regulations .
1.3.2 Know the Relevant Regulatory Requirements for Containment System and Cargo Related Operations .
1.4 Principles of Tank Atmospheres .
1.4.1 Know the Definitions Relating to Tank Atmospheres .
1.5.1 Have an Awareness of the Materials that are Used in the Construction of LNG Carriers and their Properties that Make them Suitable for Use .
1.5.2 Know and Understand the Materials that are Used in the Construction of LNG Carriers .
1.6.2 Know and Understand the Hazards to Personnel and the Ship from LNG and Relevant Gases and the Defences Applied .
1.6.4 Have an Awareness of LNG Fire-Fighting Techniques and Equipment.
1.6.5 Know and Understand LNG Fire-Fighting Techniques and Equipment .
1.7.1 Have an Awareness of the Potential Environmental Impact of LNG Operations .
1.7.2 Know and Understand the Potential Environmental Impact of LNG Operations .
1.8.2 Know and Understand the Process to Carry Out Risk Assessments of Planned Operations .
1.10.1 Have an Awareness of their Purpose and Principles.
1.10.2 Know and Understand the Contingency Planning Process .
1.11.1 Have an Awareness of the Requirements .
2.1.2 Know and Understand the Moss Type.
2.1.5 Have an Awareness of the SPB (Self-supporting, Prismatic Shape, IMO Type-B) Type .
2.1.6 Have an Awareness of the Differences Between Moss, Membrane and SPB Types .
2.2.2 Know and Understand their Operating Parameters and Limitations .
2.2.3 Know and Understand Likely Problems.
2.3.1 Have an Awareness of its Purpose and Operating Principles .
2.3.2 Know and Understand their Operating Parameters and Limitations .
2.3.4 Know and Understand Alarm Settings and Resulting Actions .
2.4.4 Know and Understand Bulk Liquid Nitrogen Storage Systems .
2.4.5 Know and Understand Alarm Settings and Resulting Actions .
2.5.1 Have an Awareness of its Purpose and Operating Principles .
2.5.2 Know and Understand its Principles, Operating Parameters, the Outlet Requirements and Limitations .
2.5.4 Know and Understand Alarm Settings and Resulting Actions .
2.6 High Duty Compressor(s) .
2.6.4 Know and Understand Alarm Settings and Resulting Actions .
2.7.4 Know and Understand Alarm Settings and the Resulting Actions .
2.8.2 Know and Understand their Principles, Operating Parameters, the Outlet Requirements and Limitations .
2.8.4 Know and Understand Alarm Settings and Resulting Actions .
2.9.1 Have an Awareness of its Purpose and Operating Principles .
2.9.2 Know and Understand its Principles, Operating Parameters, the Outlet Requirements and Limitations .
2.9.4 Know and Understand Alarm Settings and Resulting Actions .
2.10.4 Know and Understand Alarm Settings and Resulting Actions .
2.10.5 Know and Understand the Starting System.
2.11.4 Know and Understand Alarm Settings and Resulting Actions .
2.11.5 Know and Understand the Starting System.
2.13 Cargo Line Protection Devices .
2.16 Cargo Tank Protection System .
2.16.1 Have an Awareness of the Principles of Operation .
2.18 Gas Combustion Unit (Oxidiser) .
2.18.1 Have an Awareness of its Purpose and Operating Principles .
2.19.1 Have an Awareness of its Purpose and Operating Principles .
2.20 Cargo Related Spaces .
3.1 Nitrogen Pressurisation and Purge.
3.1.3 Know and Understand the Alarm Settings and Resulting Actions .
3.2.3 Know and Understand Alarm Settings and Resulting Actions .
3.3 Fixed Gas Detection .
3.3.3 Know and Understand Alarm Settings and Resulting Actions .
3.3.4 Know and Understand the Maintenance and Testing Requirements.
3.4.1 Have an Awareness of the Purpose, Use and Operating Principles .
3.4.2 Know and Understand the Purpose, Principles, Operating Parameters,Application, Calibration and Limitations.
3.4.3 Know and Understand Alarm Settings and Resulting Actions .
3.5.6 Know and Understand the Tests, Maintenance and Procedures.
3.5.7 Know and Understand Principles and Types .
3.6 Emergency Mooring Release .
3.7.1 Know and Understand the Purpose and Principles of Operation of the Water Curtain .
3.8.2 Know and Understand the Purpose and Principles of Operation of the Drenching System .
3.9 Fixed Dry Powder Installations .
3.9.1 Know the Operation and Application of the Fixed Dry Powder Fire Fighting System.
3.10.2 Know and Understand their Principles, Operating Requirements, Likely Problems and Maintenance Procedures .
3.11 Custody Transfer System (CTS).
3.12.2 Know and Understand the Operation and Maintenance of Intrinsically Safe Systems (Ex I) .
3.13.1 Know that the Operation and Maintenance of High Voltage Systems and Equipment is Subject to Specific Control Procedures .
3.14.1 Have an Awareness of the Operating Principles .
3.16.1 Have an Awareness of the Principal Types of Main Propulsion Machinery .
3.17.1 Have an Awareness of System Types .
3.17.2 Have an Awareness of the Purging and Starting Sequence for Gas Burning .
3.17.4 Know and Understand the Pre and Post Gas Burning Purge and Venting Sequences.
3.17.6 Know and Understand the Maintenance and Testing Requirements.
4.1.1 Have an Awareness of the Requirement for Cleanliness of Cargo Tanks .
4.2 Hold Space and Cargo Tank Drying .
4.2.3 Know and Understand the Operation of Inert Gas Plant to Deliver Dry Air .
4.2.4 Monitoring Procedures and Analyse Locations .
4.3.1 Have an Awareness of the Requirement and Methods of Nitrogen Purging .
4.3.4 Know and Understand the Operation of Nitrogen Generators.
4.3.6 Know and Understand Parameters to Determine Operation Completed.
4.4.1 Have an Awareness of the Procedures for Inerting the Cargo System .
4.4.2 Know and Understand the Utilisation of Cargo Tanks .
4.5.3 Know and Understand Manifold Pipeline Requirements Prior to Connection .
4.6 Gassing-Up (Purging) of Cargo System .
4.6.2 Know and Understand the Procedures for Gassing-Up the Cargo Tank .
4.8.1 Have an Awareness of Loading Procedures .
4.8.4 Have an Awareness of the Procedures for Cargo Line Draining .
4.8.5 Know and Understand the Procedures for Cargo Line Draining .
4.9.1 Have an Awareness of Cargo Management Principles .
4.11.1 Have an Awareness of Warm-Up Procedures .
4.12.1 Have an Awareness of the Principles of Gas - Freeing .
4.12.2 Know and Understand the Procedures for Gas - Freeing .
5.2.3 Know and Understand the Procedures for Pressurised Discharge .
5.3 Gas Freeing a Single Tank .
5.4 Ship to Ship Transfer of Cargo .
5.7.1 Know and Understand the Effect upon the Cargo Tank Condition When Boil-Off Gas cannot be Processed in the Machinery Space.
5.8.1 Know the Power Supply Arrangements for Cargo Equipment and Ancillaries.
5.9 Loss of Primary Barrier .
5.10.1 Know and Understand the Action to be taken in the Event of Ballast Tank Leakage into Containment Space .
5.11.1 Know and Understand Alarm Settings and Resulting Actions .
5.13 Overfilling of a Cargo Tank .
5.13.1 Know the Means by which the Alarm is Raised for Cargo Tank High Level .
5.15 Failure of Integrated Automation System .
5.15.1 Know and Understand the Procedures for Failure of the System .
6.1.1 Have an Awareness of the Following Terms and their Relevance .
6.1.3 Have an Awareness of the Basic Types of Time Charters .
6.1.4 Have an Awareness of Basic LNG Time Charter Performance Clauses .
6.1.6 Have an Awareness of Relevant Industry International Organisations and Bodies.
6.2.2 Know and Understand the Vetting and Inspection Processes .
6.3.1 Know and Understand the Information Required to Determine a Ship's Compatibility with a Terminal .
Annex - II LNG Experience Matrix .
Annex - III LNG Gallery .
4 LNG Shipping Knowledge 2nd Edition 1.1.2 Know and Understand the ‘Gas Laws’ and how they are Applicable to LNG Operations SIGTTO suggested research areas: Pressure and temperature relationship It is not only by alteration of its temperature that the volume of a gas can be changed. Changing the pressure exerted on it can also have this effect. This tells us that a gas has three quantities - volume, temperature and pressure, all of which may change. Early investigation of the physical properties of gases showed that, in certain respects, all the different gases behave in exactly the same way. Boyle’s Law The relationship between volume and pressure at constant temperature. Boyle’s Law says that, for a ?xed amount of gas (?xed number of moles) at a ?xed temperature, the pressure and the volume are inversely proportional. pV = constant In other words, as pressure increases, volume decreases. (When you squeeze on a balloon to increase the pressure, the volume of the balloon goes down.) Charles’ and Gay-Lussac’s Laws The relationship between volume and temperature at constant pressure. Charles’ Law says that for a ?xed amount of gas (?xed number of moles) at a ?xed pressure, the volume is proportional to the temperature. V/T = constant In other words, as the temperature increases, the volume increases. (When you heat a balloon the volume of the balloon goes up.) Gay-Lussac’s Law says that for a ?xed amount of gas (?xed number of moles) at a ?xed volume, the pressure is proportional to the temperature. P/T = constant In other words, as the temperature increases, the pressure increases. (When you put a pickle jar in the refrigerator, the drop in pressure from the trapped air becoming colder makes it hard to open the jar later!) Figure 1.5 Boyle’s Law Figure 1.6 Charles’ Law Physics and Chemistry 5 1.1.3 Know and Understand the Physics Relating to the Change of State of the Various Components Involved in Relation to LNG SIGTTO suggested research areas: Assuming atmospheric pressure, temperatures at which the following components change from vapour to liquid: z Butane z Propane z Ethane z Methane z Nitrogen Behaviour of CO2 relative to other components To understand how gases become lique?ed and the impact of this on containment and handling, we need to go back to some basic de?nitions and concepts. Gas, liquid and solid are the three states of matter or material. A solid has a de?nite shape and volume. A liquid has a de?nite volume but it takes the shape of a container whereas a gas ?lls the entire volume of a container. Most substances can exist in either a solid, liquid or vapour state. There are speci?c terms used for each of the changes from one state of matter to another, and these are provided below: Energy is involved in the various changes of state that occur, primarily in the form of heat. Each of the changes of state processes either uses heat or releases heat. When a solid substance changes from the solid phase to the liquid phase, energy must be supplied in order to overcome the molecular attractions between the constituent particles of the solid. This energy must be supplied externally, normally as heat, and does not bring about a change in temperature. We call this energy latent heat (the word ‘latent’ means ‘invisible’). Figure 1.8 Phase Change Gas, Liquid, Solid The two latent heats are typically described as follows. One is the latent heat of fusion (melting), and the other is the latent heat of vaporisation (evaporation). Heat of fusion is the amount of thermal energy that must be absorbed or lost for 1 gram of a substance to change state from a solid to a liquid or vice versa. It is also called the latent heat of fusion (or the enthalpy of fusion) and the temperature at which it occurs is called the melting point. When you withdraw thermal energy from a liquid or solid, the temperature falls. When you add heat energy the temperature rises. Figure 1.7 Gay-Lussac’s Law 8 LNG Shipping Knowledge 2nd Edition When these particles hit the walls of the container, they exert a pressure. This pressure is called the saturated vapour pressure (also known as saturation vapour pressure) of the liquid. A high vapour pressure means that the liquid must be volatile. Molecules escape from its surface relatively easily and aren’t very good at sticking back on again either, resulting in larger numbers of them in the gas state once equilibrium is reached. If you increase the temperature, you are increasing the average energy of the particles present. This means that more of them are likely to have enough energy to escape from the surface of the liquid, which will tend to increase the saturated vapour pressure. Temperatures at which gases change from vapour to liquid at atmospheric pressure Butaneminus 0.5°C Propaneminus 42.8°C Ethaneminus 88.6°C Methaneminus 161.5°C Nitrogenminus 195.9°C Behaviour of CO2 relative to other components/issues with CO2The main constituents of inert gas are carbon dioxide (CO2) and nitrogen (N2). On LNG Carriers, if the inerting is to be carried out using ship generated inert gas, a gassing-up operation will also be necessary as CO2 will freeze at temperatures below minus 56.6°C and so will contaminate the cargo if brought in direct contact with LNG (at minus 161.5°C). Solid CO2 would also create operational dif?culties as it can block or damage valves and pumps. More commonly, CO2 produces a white powder that can block ?lters and nozzles. Carbon Dioxide is a risk in contact with LNG as it freezes at minus 56.6°C LNG compositions (%mol) CH4(Methane) C2H6 (Ethane) C3H8 (Propane) C4H10(Butane) C5H12(Pentane) N2(Nitrogen) Arzew (Algeria)87.18.62.10.050.020.35 Bintulu (Malaysia)91.231.32.951.100.12 Bonny (Nigeria)90.15.22.81.50.020.07 Das Island (UAE)81.5313.391.310.2800.17 Arun (Indonesia)89.337.142.221.170.010.08 Kenai (Alaska)99.80.100.100.1 Lumut (Brunei)89.46.32.81.30.050.05 Marsa El Brega (Libya)7015103.50.60.9 Point Fortin (Trinidad)96.23.260.420.070.010.008 Ras Laffan (Qatar)90.16.172.270.60.030.25 Skikda (Algeria)91.55.611.50.50.010.85 Withnell (Australia)89.027.332.561.0300.06 Learn more about the properties of LNG by viewing a 2min 19s video that is available by searching for ‘LNG Properties Video’ on You Tube. Alternatively view at: http://tinyurl.com/LNG-Properties 13 1.2 Principles of Design 1.2.1 Have an Awareness of Main Design Principles Figure 1.12 LNGC under construction, Shanghai 2011 SIGTTO suggested research areas: Be aware of the principles for protection of cargo containment systems Principles for protection of cargo containment systems LNG Carriers should survive the normal effects of ?ooding following the expected hull damage from incidents such as grounding, collision and stranding. The cargo tanks are protected from ?ooding by positioning them at speci?ed minimum distances inboard from the ship’s side. The construction guidelines for LNG carriers are found in ‘The International Code for the Construction and Equipment of Ships Carrying Lique?ed Gases in Bulk’, commonly known as the IGC Code, which details the following main design principles for Lique?ed Gas Carriers: Damage assumptions: The maximum assumed extent of damage is: 1 Longitudinal extent: 1/3Length 2/3 or 14.5 m, whichever is less 2 Transverse extent: Breadth/5 or 11.5 m, whichever is less 3 Vertical extent:Upwards without limit Secondary Barrier: The secondary barrier is to act as a temporary containment for any envisaged leakage of liquid cargo from the primary barrier. It is designed to contain any leakage for a period of at least 15 days. Insulation: Suitable insulation should be provided to ensure that the temperature of the hull structure does not fall below the minimum allowable design temperature for the grade of steel concerned. Cargo tank vent systems: Cargo tanks should be provided with a pressure relief system appropriate to the design of the cargo containment system and the cargo being carried. Note. This relief system for the cargo tanks protects against over- pressurisation and vacuum. Hold spaces, interbarrier spaces and cargo piping, which may be subject to pressures beyond their design capabilities, should also be provided with a suitable pressure relief system.