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# General information and Rules for Ships carrying LNG and LPG

Article contains general information, character of classification, definitions, surveys and certification and rules for ships carrying LNG and LPG.

## General

These Rules apply to ships having their machinery aft and built for the carriage in bulk of liquefied gases and some other products which are listed in article “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements.

In addition to these Rules the relevant requirements of Rules for Classification and Surveys (Part 1, Vol. I) , Rules for Hull (Part 1, Vol. II) Sec. 1, 22 , Rules for Hull (Part 1, Vol. II) Sec. 1, 23 and Rules for Hull (Part 1, Vol. II) Sec. 1, 24, apply.

For the machinery, the electrical plant and the refrigerating installation of these ships, Rules for Machinery Installations (Part 1, Vol. III), Rules for Electrical Installations (Part 1, Vol. IV) and Rules for Automation (Part 1, Vol. VII), apply.

These Rules incorporate the IMO-Resolution MSC.220(82) “International Code for the Construction and Equipment of Ships carrying liquefied Gases in Bulk” (IGC-Code), consolidate edition as amended.

Certain requirements of the IGC-Code that are not within the scope of classification, e.g. “Equivalents”, “Personal protection of crew on Gas Carriers”Protective equipment, “Personnel Protection”, certain operational requirements in “Special Requirements for LNG and LPG gas carriers”Special Requirements “Special Requirements” and “Operating Requirements for Ships carrying liquefied gas”Operating Requirements “Operating Requirements” have been included in these rules.

Except for paragraph above and for operational requirements as mentioned above they will, however, be applied in such instances where

1. The Society is authorized by Administrations to issue on their behalf the “Certificate of Fitness for the Carriage of Liquefied Gases in Bulk”.
2. Or where the Society is authorized to carry out investigations and surveys on behalf of Administrations on the basis of which the “Certificate of Fitness for the Carriage of Liquefied Gases in Bulk” will be issued by the Administrations.
3. The Society is requested to certify compliance with the IGC-Code.

The term “should be” in the respective paragraphs or articles is in such cases to be read as “is” or “are to be” or “shall be”. Operating Requirements have been included for guidance only and will not be looked at by the Society.

Specific requirements of the Society which are additional to the provisions of the IGC-Code as well as interpretations of some Code requirements have been identified by a special paragraph. No. (e.g. 4.2-b) and highlighted. Alterations to the preceding Edition are marked by underline. Differing from the standard construction of the Rules, which is given in this article, articles “Rules for Ships Carrying Liquefied Gases”Rules for LNG/LPG carriers for direct comparison with the IGC-Code are arranged accordingly.

### Equivalents

Where the IGC-Code requires that a particular fitting, material, appliance, apparatus, item of equipment or type thereof should be fitted or carried in a ship, or that any particular provision should be made, or any procedure or arrangement should be complied with, the Administration may allow any other fitting, material, appliance, apparatus, item of equipment or type there of to be fitted or carried, or any other provision, procedure or arrangement to be made in that ship, if it is satisfied by trial thereof or otherwise that such fitting, material, appliance apparatus, item of equipment or type thereof or that any particular provision, procedure or arrangement is at least as effective as that required by the IGC-Code.

However, the Administration may not allow operational methods or procedures to be made an alternative to a particular fitting, material, appliance, apparatus, item of equipment, or type thereof which is prescribed by the IGC-Code.

When an Administration so allows any fitting, material, appliance, apparatus, item of equipment, or type thereof, or provision, procedure or arrangement to be substituted, it should communicate to the Organization the particulars thereof together with a report on the evidence submitted, so that the Organization may circulate the same to other Contracting Governments to the 1974 SOLAS Convention for the information of their officers.

### Application of the IGC-Code

The IGC-Code applies to ships regardless of their size, including those of less than 500 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 “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements of the IGC-Code, when carried in bulk.

Unless expressly provided otherwise, the IGC-Code applies to ships the keels of which are (were) laid or which are (were) at a stage at which:

• construction identifiable with the ship begins;
• and assembly of that ship has commenced comprising at least 50 tonnes or 1 % of the estimated mass of all structural material whichever is less;

on or after 1 July 1998.

Ships constructed before 1 July 1998 are to comply with resolution MSC.5 (48) adopted on 17 June 1983 subject to amendments by resolution MSC.30 (61) adopted on 11 December 1992.

A ship, irrespective of the date of construction, which is converted to a gas carrier on or after July 1st, 1998 shall be treated as a gas carrier constructed on the date on which such conversion commences.

When cargo tanks contain products for which the IGC-Code requires a type 1G-ship, neither flammable liquids having a flashpoint of 60 °C (closed cup test) or less nor flammable products listed in “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements of the IGC-Code shall be carried in tanks located within the protective zones described in “Ship Survivability and Cargo Tanks Placement”Location of cargo tanks.

Similarly, when cargo tanks contain products for which the IGC-Code requires a type 2G/2PG-ship, the above mentioned flammable liquids shall not be carried in tanks located within the protective zones described in “Ship Survivability and Cargo Tanks Placement”Location of cargo tanks.

In each case the restriction applies to the protective zones within the longitudinal extent of the hold spaces for the cargo tanks loaded with products for which the IGC-Code requires a type 1G or 2G/2PG-ship. The above mentioned flammable liquids and products may be carried within these protective zones, when the quantity retained in the cargo tanks of products for which the IGC-Code requires a type 1G or 2G/2PG-ship is solely used for cooling, circulation or fuelling purposes.

Except as provided in list below, when it is intended to carry products covered by the IGC-Code and products covered by the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk, IMO-Resolution MEPC.119(52) and MSC.219(82), (IBC-Code), as may be amended by the Organization, the ship shall comply with the requirements of both Codes appropriate to the products carried.

Where it is proposed to carry products which may be considered to come within the scope of the Code but are not at present designated in “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements, the Administrations and the Port Administrations involved in such carriage shall establish suitable conditions of carriage based on the principles of the Code and notify the Organization of such conditions.

The requirements of the IGC-Code should take precedence when a ship is designed and constructed for the carriage of the following products:

1. those listed exclusively in “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements;
2. and one or more of the products which are listed both in “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements and Rules for Carrying Dangerous Chemical in Bulk (Part 1, Vol. X) Sec. 17. These products are marked with an asterisk (*) in column “a” of “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements.

When a ship is intended exclusively to carry one or more of the products noted in Rules for Carrying Dangerous Chemical in Bulk (Part 1, Vol. X) Sec., i.e. those of the IBC-Code as amended shall apply.

Compliance of the ship with the requirements of the International Gas Carrier Code shall be shown in the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk. Compliance with the amendments to the Code, as appropriate, should also be indicated in the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk.

### Hazards

Hazards of gases considered in the IGC-Code include:

• fire;
• toxicity;
• corrosivity;
• reactivity;
• low temperature and pressure.

## Character of Classification, Entries into the Class Certificate, Documents for Approval

### Character of Classification

Ships complying with the requirements of these Rules will have the Notation: LIQUEFIED GAS CARRIER affixed to the Character of Classification.

Liquefied gas carriers will be assigned the symbol □ before the Character of Classification for characterizing proof of damage stability according to the IGC-Code (Section 2) and after the Character of Classification the relevant ship type notation (Type 1G, 2G, 2PG or 3G).

The following data will be entered into an appendix to the Certificate:

1. Five digit code for the specification of the proof of damage stability according to Rules for Classification and Surveys (Part 1, Vol. I) Sec. 2, C.2.4.2.
2. Description of the code.

Liquefied gas carriers equipped with cargo refrigeration system according to article “Cargo Temperature Control and Cargo Vent Systems”Refrigeration systems will have the notation RI affixed to the Character of Classification for the machinery plant.

For liquefied gas carriers a list stating the products permitted to be carried will be issued as an annex to the IMO Certificate of Fitness.

### Documents for approval

Apart from the documents listed in Rules for Hull (Part 1, Vol. II) Sec. 1, G, the following documents are to be submitted in triplicate to BKI. To facilitate a smooth and efficient approval process the drawing could be submitted in electronic format:

1. general arrangement plan;
2. data on the location and capacity of cargo tanks and products to be carried;
3. scantlings and stress analysis of cargo tanks and secondary barrier, if any;
4. data of the foundations and the fastening of the cargo tanks and relevant stress analysis;
5. calculation of the lowest temperatures of the hull structure considering the insulation according to “Cargo containment system of gas vessel”Insulation with data on the material selection for the hull;
6. data on the ship’s ballast condition;
7. damage stability calculations if this Society is acting in accordance with A.5.1 to “scantlings and stress analysis of cargo tanks and secondary barrier”;
8. drawings showing the arrangement of access and inspection openings for compliance with the requirements in article “Arrangement of the gas carrier ships”Access to spaces in the cargo area (in particular double bottom and double hull).

Apart from the documents listed in Rules for Machinery Installations (Part 1, Vol. III) Sec, 15, A.3 the following documents are to be submitted in triplicate to BKI.

To facilitate a smooth and efficient approval process the drawing could be submitted in electronic format:

1 plans of cargo piping, arrangement of cargo pumps and their drives;

2 plans and calculations of process pressure vessels, valves;

3 plans of gas or vapour pipes of the safety relief valves;

4 plans and calculation of the safety relief valves;

5 plans of fire extinguishing in the cargo area;

6 plans of bilge and ballast arrangements in the cargo area;

7 data on gas-freeing of the cargo containment system, including data on the inert gas plant with assembly and piping plans;

8 plans for the ventilation of spaces within the cargo area;

9 data on the gas detection system for the various substances to be transported;

10 data on the instrumentation of cargo tanks as per “Cargo Tank Instrumentation on Gas Tankers”Cargo tank instrumentation and data on the temperature monitoring of the hull structure, if required;

11 description of cargo handling operations;

12 data on the insulation and proof of its suitability. Proof of sufficient thermal insulation. Calculation of the boil-off rate for the lay-out of the refrigeration plant, if any;

13 wiring plan including data on certified safe type equipment in gas dangerous spaces and zones;

14 For machinery using gas as fuel:

• general arrangement plan of the machinery plant;
• gas piping plans for the machinery plant;
• complete list of the safety, gas detection and warning equipment;
• drawings of the internal combustion engines;
• drawings of the boilers;
• drawings of the gas turbines;
• detail drawings of the gas inlet and fuel inlet equipment;
• gas characteristics;
• general arrangement plan of the gas treatment plant, including gas compressors, prime movers and gas preheaters;
• drawings of the gas storage tanks;
• drawings of the gas compressors and preheaters;
• description of the entire plant;

15 For Refrigerating Installations the documents listed in Automation (Part 1, Vol. VII) Sec. 1, A. if applicable – are to be submitted.

## Definitions

Except where expressly provided otherwise, the following definitions apply. Additional definitions are given in article “Cargo containment system of gas vessel”Cargo containment system.

Accommodation Spaces are those spaces used for public spaces, corridors, lavatories, cabins, offices, hospitals, cinemas, games and hobbies rooms, barber shops, pantries containing no cooking appli-ances and similar spaces. Public spaces are those portions of the accommodation which are used for halls, dining rooms, lounges and similar permanently enclosed spaces.

“A” Class Divisions means divisions as defined in SOLAS regulation II-2/3.2.

Administration means the Government of the state whose flag the ship is entitled to fly.

Anniversary date means the day and the month of each year which will correspond to the date of expiry of the Certificate of Fitness for the Carriage of Liquefied Gases in Bulk.

Boiling Point is the temperature at which a product exhibits a vapour pressure equal to the atmospheric barometric pressure.

Breadth B means the maximum breadth of the ship, measured amidships to the moulded line of the frame in a ship with a metal shell and to the outer surface of the hull in a ship with a shell of any other material. The breadth (B) should be measured in metres. For scantling purposes the breadth B defined in Part 1 Seagoing Ship, Volume II Hull, Section 1, H.2.5 applies.

Cargo Area is that part of the ship which contains the cargo containment system and cargo pump and compressor rooms and includes deck areas over the full beam and length of the ship above the foregoing. Where fitted, the cofferdams, ballast or void spaces at the after end of the aftermost hold space or at the forward end of the forwardmost hold space are excluded from the cargo area.

Cargo Containment System is the arrangement for containment of cargo including, where fitted, a primary and secondary barrier, associated insulation and any intervening spaces, and adjacent structure if necessary for the support of these elements. If the secondary barrier is part of the hull structure it may be a boundary of the hold space.

Cargo Control Room is a space used in the control of cargo handling operations and complying with the requirements of “Arrangement of the gas carrier ships”Cargo control rooms.

Cargoes are products listed in “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements carried in bulk by ships subject to the Code.

Cargo Service Spaces are spaces within the cargo area used for workshops, lockers and store rooms of more than 2 m2 in area, used for cargo handling equipment.

Cargo Tank is the liquid-tight shell designed to be the primary container of the cargo and includes all such containers whether or not associated with insulation or secondary barriers or both.

Cofferdam is the isolating space between two adjacent steel bulkheads or decks. This space may be a void space or a ballast space.

Control Stations are those spaces in which ship’s radio or main navigating equipment or the emergency source of power is located or where the fire recording or fire control equipment is centralized. This does not include special fire control equipment which can be most practically located in the cargo area.

Flammable Products are those identified by an “F” in column “f” in the table of “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements.

Flammability Limits are the conditions defining the state of fuel-oxidant mixture at which application of an adequately strong external ignition source is only just capable of producing flammability in a given test apparatus.

Gas Carrier is a cargo ship constructed or adapted and used for the carriage in bulk of any liquefied gas or other substance listed in the table in “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements.

Gas-Dangerous Space or Zone is:

• space in the cargo area which is not arranged or equipped in an approved manner to ensure that its atmosphere is at all times maintained in a gas-safe condition;
• an enclosed space outside the cargo area through which any piping containing liquid or gaseous products passes, or within which such piping terminates, unless approved arrangements are installed to prevent any escape of product vapour into the atmosphere of that space;
• a cargo containment system and cargo piping;
• a hold space where cargo is carried in a cargo containment system requiring a secondary barrier;
• a hold space where cargo is carried in a cargo containment system not requiring a secondary barrier;
• a space separated from a hold space described above by a single gas-tight steel boundary;
• a cargo pump room and cargo compressor room;
• a zone on the open deck, or semi-enclosed space on the open deck, within 3 m of any cargo tank outlet, gas or vapour outlet, cargo pipe flange or cargo valve or of entrances and ventilation openings to cargo pump rooms and cargo compressor rooms;
• the open deck over the cargo area and 3 m forward and aft of the cargo area on the open deck up to a height of 2,4 m above the weather deck;
• a zone within 2,4 m of the outer surface of a cargo containment system where such surface is exposed to the weather;
• an enclosed or semi-enclosed space in which pipes containing products are located. A space which contains gas detection equipment complying with “Cargo Tank Instrumentation on Gas Tankers”Gas detection requirements and a space utilizing boil-off gas as fuel and complying with article “Use of Cargo as Fuel on Gas Tankers”Use of cargo as fuel are not considered gas-dangerous spaces in this context;
• a compartment for cargo hoses;
• or an enclosed or semi-enclosed space having a direct opening into any gas-dangerous space or zone.

Gas-Safe Space is a space other than a gas-dangerous space.

Hold Space is the space enclosed by the ship’s structure in which a cargo containment system is situated.

Independent means that a piping or venting system, for example, is in no way connected to an-other system and there are no provisions available for the potential connection to other systems.

Insulation Space is the space, which may or may not be an inter barrier space, occupied wholly or in part by insulation.

Inter barrier Space is the space between aprimary and a secondary barrier, whether or not com-pletely or partially occupied by insulation or other material.

Length (Lc) means 96 % of the total length on a waterline at 85 % of the least moulded depth measured from the top of the keel, or the length from the foreside of the stem to the axis of the rudder stock on that waterline, if that be greater. In ships designed with a rake of keel, the waterline on which this length is measured shall be parallel to the designed waterline. The length (Lc) shall be measured in metres. For scantling purposes the length L defined in Part 1 Seagoing Ship, Volume II Hull, Section 1, H.2.1 applies.

Machinery Spaces of Category A are those spaces and trunks to such spaces which contain:

• internal combustion machinery used for main propulsion;
• or internal combustion machinery used for purposes other than main propulsion where such machinery has in the aggregate a total power output of not less than 375 kW;
• or any oil-fired boiler or oil fuel unit.

Machinery Spaces are all machinery spaces of category A and all other spaces containing:

• propelling machinery;
• boilers;
• oil fuel units;
• steam and internal combustion engines;
• generators and major electrical machinery;
• oil filling stations;
• refrigerating;
• stabilizing;
• ventilation and air conditioning machinery, and similar spaces;
• and trunks to such spaces.

MARVS is the maximum allowable relief valve setting of a cargo tank.

Oil Fuel Unit is the equipment used for the preparation of oil fuel for delivery to an oil-fired boiler, or equipment used for the preparation for delivery of heated oil to an internal combustion engine, and includes any oil pressure pumps, filters and heaters dealing with oil at a pressure of more than 1,8 bar.

Organization is the International Maritime Organization (IMO).

Permeability of a space means the ratio of the volume within that space which is assumed to be occupied by water to the total volume of that space.

Primary Barrier is the inner element designed to contain the cargo when the cargo containment system includes two boundaries.

Secondary Barrier is the liquid-resisting outer element of a cargo containment system designed to afford temporary containment of any envisaged leakage of liquid cargo through the primary barrier and to prevent the lowering of the temperature of the ship’s structure to an unsafe level. Types of secondary barrier are more fully defined in “Cargo containment system of gas vessel”Cargo containment system.

Recognized Standards are applicable international or national standards acceptable to the Administration or standards laid down and maintained by an Organization which complies with the standard adopted by the Organization and which is recognized by the Administration. (This definition includes the BKI-Rules).

Relative Density is the ratio of the mass of a volume of a product to the mass of an equal volume of fresh water.

Separate means that a cargo piping system or cargo vent, for example, is not connected to another cargo piping or cargo vent system. This separation may be achieved by the use of design or operational methods. Operational methods shall not be used within a cargo tank and should consist of one of the following types:

• removing spool pieces or valves and blanking the pipe ends;
• arrangement of two spectacle flanges in series with provisions for detecting leakage into the pipe between the two spectacle flanges.

Service Spaces are those spaces used for galleys, pantries containing cooking appliances, lockers, mail and specie rooms, store rooms, workshops other than those forming part of the machinery spaces and similar spaces and trunks to such spaces.

Society is the Biro Klasifikasi Indonesia.

SOLAS means the International Convention for the Safety of Life at Sea, 1974, as amended.

Tank Cover is the protective structure intended to protect the cargo containment system against damage where it protrudes through the weather deck or to ensure the continuity and integrity of the deck structure.

Tank Dome is the upward extension of a portion of the cargo tank. In the case of below deck cargo containment systems the tank dome protrudes through the weather deck or through a tank cover.

Toxic Products are identified by a “T” in column “f” of the table in “Summary of Minimum Requirements for LNG and LPG tankers”Minimum Requirements.

Vapour Pressure is the equilibrium pressure of the saturated vapour above the liquid expressed in bar absolute at a specified temperature.

Void Space is the enclosed space in the cargo area external to a cargo containment system, other than a hold space, ballast space, fuel oil tank, cargo pump or compressor room, or any space in normal use by personnel.

## Surveys and Certification

Surveys for class maintenance

The relevant requirements are given in Rules for Classification and Surveys (Part 1, Vol. I) Sec. 4, D.

Survey and certification according to IGC-Code

The relevant requirements of Section 1.5 of the IGC-Code are given in Part 1-Seagoing Ship, Volume I Rules for Classification and Surveys, Section 4, D.

## Emergency Towing Arrangements

Emergency towing arrangements are to be fitted on liquefied gas carriers of 20 000 tdw and above in accordance with the 1974 SOLAS Convention, Chapter II-1, Reg. 3-4, see also Rules for Hull (Part.1, Vol. II), Section 24, A.10.

Every liquefied gas carrier shall be equipped with means for safe access to the bow in accordance with, SOLAS, Chapter II-1; Reg. 3-3 and ICLL, Reg. 25 (4), 26 (2), 27 (7) (see also IACS U. I. LL 50).

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