MODULE 2L: Carriage of Liquefied Gases in Bulk

1. The purpose of the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) is to provide an international standard for the safe carriage by sea in bulk of liquefied gases and certain other substances listed in chapter 19 of the IGC Code, by prescribing the design and construction standards of ships involved in such carriage and the equipment they should carry so as to minimize the risk to the ship, to its crew and to the environment, having regard to the nature of the products involved.

True

False

2. The IGC Code applies to ships regardless of their size, including those of less than 500 tons gross tonnage, engaged in carriage of liquefied gases having a vapour pressure exceeding 2.8 bar absolute at a temperature of 37.8°C, and other products as shown in chapter 19 of the IGC Code, when carried in bulk.

True

False

3. The structure, equipment, fittings, arrangements and material (other than items in respect of which a Cargo Ship Safety Construction Certificate, Cargo Ship Safety Equipment Certificate and Cargo Ship Safety Radio Certificate or Cargo Ship Safety Certificate are issued) of a gas carrier should be subjected to the following surveys:

an initial survey before the ship in put in service or before the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk is issued for the first time, which should include a complete examination of its structure, equipment, fittings, arrangements and material in so far as the ship is covered by the Code. This survey should be such as to ensure that the structure, equipment, fittings, arrangements and material fully comply with the applicable provisions of the Code;

a renewal survey at intervals specified by the Administration, but not exceeding 5 years. The renewal survey should be such as to ensure that the structure, equipment, fittings, arrangements and material fully comply with the applicable provisions of the Code;

an intermediate survey within 3 months before or after the second anniversary date or within 3 months before or after the third anniversary date of the Certificate which should take the place of one of the annual surveys. The intermediate survey should be such as to ensure that the safety equipment, and other equipment, and associated pump and piping systems fully comply with the applicable provisions of the Code and are in good working order. Such intermediate surveys should be endorsed on the Certificate issued;

an annual survey within 3 months before or after each anniversary date of the Certificate, including a general inspection of the structure, equipment, fittings, arrangements and material to ensure that they have been maintained and that they remain satisfactory for the service for which the ship is intended. Such annual surveys should be endorsed on the Certificate issued;

All of the above

4. Ships subject to the IGC Code should be designed to one of the following standards:

Type 1G ship is a gas carrier intended to transport products indicated in chapter 19 which require maximum preventive measures to preclude the escape of such cargo.

Type 2G ship is a gas carrier intended to transport products indicated in chapter 19 wich require significante preventiv e measures to preclude the escape of such cargo.

Type 2PG ship is a gas carrier of 150m in length or less intended to transport products indicated in chapter 19 which require significant preventive measures to preclude escape of such cargo, and where the products are carried in independent type C tanks designed for a MARVS of at least 7 bar gauge and a cargo containment system design temperature of -55°C or above. Note that a ship of this description but over 150m in length is to be considered a Type 2G ship.

Type 3G ship is a gas carrier intended to carry products indicated in chapter 19 which require moderate preventive measures a) True to preclude the escape of such cargo

All of the above are correct answers

5. Shipside discharges below the freeboard deck: The provision and control of valves fitted to discharges led through the shell from spaces below the freeboard deck or from within the superstructures and deckhouses on the freeboard deck fitted with weathertight doors should comply with the requirements of the relevant regulation of the International Convention on Load Lines in force, except that the choice of valves should be limited to:

one automatic non-return valve with a positive means of closing from above the freeboard deck; or

where the vertical distance from the summer load waterline to the inboard end of the discharge pipe exceeds 0.01L, two automatic non-return valves without positive means of closing, provided that the inboard valve is always accessible for examination under service conditions

All of the above are correct answers

6. Cargo tanks should be located at the following distances inboard:

Type 1G ships: from the side shell plating not less than the transverse extent of damage and from the moulded line of the bottom shell plating at centreline not less than the vertical extent of damage and nowhere less than 760 mm from the shell plating.

Types 2G/2PG and 3G ships: from the moulded line of the bottom shell plating at centreline not less than the vertical extent of damage and nowhere less than 760 mm from the shell plating

All of the above are correct answers

7. Hold spaces should be segregated from machinery and boiler spaces, accommodation spaces, service spaces and control stations, chain lockers, drinking and domestic water tanks and from stores. Hold spaces should be located forward of machinery spaces of category A, other than those deemed necessary by the Administration for the safety or navigation of the ship.

True

False

8. Cargo pump rooms and cargo compressor rooms should be situated above the weather deck and located within the cargo area unless specially approved by the Administration. Cargo compressor rooms should be treated as cargo pump rooms for the purpose of fire protection according to SOLAS regulation II-2/9.2.4.

True

False

9. Any cargo control room should be above the weather deck and may be located in the cargo area. The cargo control room may be located within the accommodation spaces, service spaces or control stations provided the following conditions are complied with:

the cargo control room is a gas-safe space; and

if the entrance complies with 3.2.4 of the IGC Code, the control room may have access to the spaces described above;

if the entrance does not comply with 3.2.4 of the IGC Code, the control room should have no access to the spaces described above and the boundaries to such spaces should be insulated to A-60 class integrity.

All of the above

10. Access to spaces in the cargo area should be provided to

cargo tanks direct from the open deck;

through horizontal openings, hatches or manholes, the dimensions of which should be sufficient to allow a person wearing a breathing apparatus to ascend or descend any ladder without obstruction and also to provide a clear opening to facilitate the hoisting of an injured person from the bottom of the space; the minimum clear opening should be not less than 600 mm x 600 mm; and

through vertical openings, or manholes providing passage through the length and breadth of the space, the minimum clear opening of which should be not less than 600 mm by 800 mm at a height of not more than 600 mm from the bottom plating unless gratings or other footholds are provided.

All of the above

11. Integral tanks form a structural part of the ship's hull and are influenced in the same manner and by the same loads which stress the adjacent hull structure.

True

False

12. Membrane tanks are non-self-supporting tanks which consist of a thin layer (membrane) supported through insulation by the adjacent hull structure. The membrane is designed in such a way that thermal and other expansion or contraction is compensated for without undue stressing of the membrane.

True

False

13. Every cargo piping system and cargo tank should be provided with the following valves, as applicable:

For cargo tanks with a MARVS not exceeding 0.7 bar gauge, all liquid and vapour connections, except safety relief valves and liquid level gauging devices, should have shutoff valves located as close to the tank as practicable. These valves may be remotely controlled but should be capable of local manual operation and provide full closure.

For cargo tanks with a MARVS exceeding 0.7 bar gauge, all liquid and vapour connections, except safety relief valves and liquid level gauging devices, should be equipped with a manually operated stop valve and a remotely controlled emergency shutdown valve. These valves should be located as close to the tank as practicable.

Cargo pumps and compressors should be arranged to shutdown automatically if the emergency shutdown valves are closed by the emergency shutdown system

All of the above

14. All cargo tanks should be provided with a pressure relief system appropriate to the design of the cargo containment system and the cargo being carried. 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. The pressure relief system should be connected to a vent piping system so designed as to minimize the possibility of cargo vapour accumulating on the decks, or entering accommodation spaces, service spaces, control stations and machinery spaces, or other spaces where it may create a dangerous condition.

True

False

15. The refrigeration system may be arranged in one of the following ways:

a direct system where evaporated cargo is compressed, condensed and returned to cargo tanks. For certain cargoes specified in chapter 17 this system should not be used;

an indirect system where cargo or evaporated cargo is cooled or condensed by refrigerant without being compressed;

a combined system where evaporated cargo is compressed and condensed in a cargo/refrigerant heat exchanger and returned to the cargo tanks. For certain cargoes specified in chapter 17 this system should not be used.

All of the above are correct answers

16. A piping system should be provided to enable each cargo tank to be safely gas-freed, and to be safely purged with cargo gas from a gas-free condition. The system should be arranged to minimize the possibility of pockets of gas or air remaining after gas-freeing or purging

True

False

17. Safety equipment: Sufficient, but not less than two complete sets of safety equipment in addition to the firemen's outfits, permitting personnel to enter and work in a gas-filled space, should be provided. One complete set of safety equipment should consist of:

one self-contained air-breathing apparatus not using stored oxygen, having a capacity of at least 1,200 liters of free air;

protective clothing, boots, gloves and tight-fitting goggles;

steel-cored rescue line with belt; and

explosion-proof lamp.

All of the above

18. Methane (LNG) is the only cargo whose vapour or boil-off gas may be utilized in machinery spaces of category A and in such spaces may be utilized only in boilers, inert gas generators, combustion engines and gas turbines. These provisions do not preclude the use of gas fuel for auxiliary services in other locations, provided that such other services and locations should be subject to special consideration by the Administration.

True

False

19. Information should be on board and available to all concerned, giving the necessary data for the safe carriage of cargo. Such information should include for each product carried: a full description of the physical and chemical properties necessary for the safe containment of the cargo; action to be taken in the event of spills or leaks; counter-measures against accidental personal contact; fire-fighting procedures and firefighting media; procedures for cargo transfer, gas-freeing, ballasting, tank cleaning and changing cargoes; special equipment needed for the safe handling of the particular cargo; minimum allowable inner hull steel temperatures; and emergency procedures.

True

False