Section 3 Gas Supply Line System

301. General

1. The gas supply-line system is to be either a solid piping system in accordance with 302., except for short hose connections to gimbaled stoves, or continuous hoses in accordance with 303.

2. Hoses are to be used to connect gimbaled stoves to their gas supply, and supply piping to the pressure regulator. The hose and its connections between supply piping and the pressure regulator are to be within the cylinder locker or cylinder housing.

3. The piping and hose are to be sized so that the pressure drop due to pipe resistance does not re- duce the working pressure at any appliance below the value required by the appliance manufacturer when all appliances are operating simultaneously(See Annex A of ISO 10239).

302. Piping

1. Only solid drawn coper piping or drawn stainless steel piping, which are galvanically compatible, are to be used for rigid supply lines. The minimum wall thickness is to be 0.8 mm.

2. Except for bulkhead fittings, there is to be no joints or fittings in piping that passes through en- gine compartments.

3. Metallic gas supply piping routed through engine compartments is to be protected by conduit or trunking or be supported by non-abrasive attachments which are no more than 300 mm apart.

4. Fittings for connections and joints in piping are to be metallic and of any of the

(1) Hard soldered connections;

(2) Cutting-ring fittings in accordance with Table 3 of ISO 8434-1;

(3) Compression fittings of copper alloy with copper rings on copper piping;

(4) Stainless steel rings on stainless steel piping.

A jointing compound shall not be used on compression or flared fittings.

5. Piping is to be installed as high as practicable above the bilge water level.

6. Supply piping is to be made up with as few fittings as practicable joints and readily accessible.

following types:

fittings are to be

303. Hoses and hose lines

1. Hose assemblies for gas installations are to meet the requirements of EN 1763-1 and EN 1763-2, Class 2 or 3 for the low-pressure side and Class 3 or 4 for the supply pressure side.

2. Hoses are not to be routed through an engine compartment and are to be of minimum practical length.

3. Hoses are to have permanently attached end fittings, such as swaged sleeve or sleeve and threaded insert, in accordance with EN 1763-2, and are to be accessible for inspection over their entire length. Connections are to be readily accessible.

4. Hose connections are to be stress free, i.e. not subjected to tension or kinking under any conditions of use.

5. Hoses used for the gas supply line are to be continuous and have no joints or fittings from within the cylinder locker or cylinder housing to the appliances, or the readily accessible shut-off valve near the appliance except where metallic supply piping is connected to a flexible hose leading to a movable appliance, such as a gimbaled stove.

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304. Materials

1. The melting point of materials at welded or brazed connections is not to be less than 450 °C.

2. Fittings are to be galvanically compatible with the metallic piping to which they are connected.

3. Hose c1amps, if used to secure cylinder-locker vent hoses, are to be made of corrosion-resistant material, such as stainless steel, of type 18Cr 8Ni, or equivalent corrosion resistant material, and be reusable.

4. End-connecting fittings are to be of corrosion-resistant material such as brass or stainless steel, or be of equivalent corrosion resistance in marine environment.

5. Where cutting-ring fittings are used in conjunction with copper piping, a brass insertion sleeve and brass cutting ring are to be fitted. All components are to be matched, i.e. of the same series.

305. Instailation

1. Piping is not to have direct contact with metallic parts of the craft structure.

2. Gas supply lines and components are to be routed at least 30 mm away from electrical conductors, unless the gas supply line passes through a jointless conduit, or the conductors are sheathed or in conduit or trunking in accordance with ISO 10133 and ISO 13297.

3. Gas supply lines are to be at least 100 mm from components of the engine exhaust system.

Metallic gas lines are to be at least 100 mm from exposed terminals of electrical devices or accessories.

4. Gas supply lines are to be supported by fixing devices or other means, such as inside vented, non- metallic, supported conduit or piping, to prevent chafing or vibration damage. For copper or stainless steel piping, such fixing devices are to be pipe rings spaced at intervals not exceeding 0.5 m, and hoses by the fixing devices not more than 1 m. The fixing devices are to be corrosion re- sistant, non- abrasive, designed to prevent cutting or other damage to the lines and compatible with the line material.

5. All joints and connections in piping and hose in the systems are to be made such that no undue stress is created at the fitting.

6. Piping and hoses passing through bulkheads intended to maintain watertight integrity in the craft at the level of penetration are to be sealed by materials or fittings capable of maintaining the water tightness.

7. Piping and hoses are to be protected from abrasion or chafing at the point where they pass through walls or bulkheads.

8. All threaded connections required to ensure gas tightness of the system are to be of the tap- er-pipe- thread type conforming with ISO 7-1 and using sealants conforming to EN 751-2 or EN 751-3. Sealants are to be applied to the male thread only, before assembly.

306. Shut-off valves

1. Each gas system is to be equipped with a readily accessible manually operated main shut-off valve in the supply-pressure side. The main shut-off valve can be the cylinder valve. The main shut-off valve may be incorporated in the regulator, as long as its action isolates the cylinder contents from the regulator input and removal of the pressure regulator from the cylinder closes the cylinder valve.

2. A dual cylinder system is to be provided with an automatic or manual change-over device (selector valve), with non-return valves fitted, in addition to each cylinder shut-off valve, to prevent the es- cape of gas when either cylinder is disconnected.

3. A shut-off valve is to be installed in the low-pressure supply line to each appliance. The valve or its control is to be readily accessible and operable from within the vicinity of the appliance, and operable without reaching over the top of open-flame appliances such as stoves. If there is only

one appliance in the system and the main shut-off valve at the cylinder is the vicinity of the appliance, the shut-off valve on the low-pressure supply

readily accessible from line is not required. A

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solenoid valve located within the cylinder locker or cylinder housing, operable from the vicinity of the appliance, is considered as meeting this requirement. Solenoid valves are to be closed by lack of tension i.e. loss of electrical actuating energy.

4. Controls of shut-off valves in the low-pressure side of the system are to be readily accessible.

Unmistakable and easily recognized means of identifying the open and closed positions are to be

provided.

5. For shut-off valves which are not located immediately adjacent to the appliance that they control, means of identifying the appliance controlled are to be provided. If a valve is not visible, its loca- tion is to be clearly indicated with a visible and permanent label.

6. Taper-plug type valves are to be spring loaded and may be used only in the low-pressure side of the system.

7. Shut-off valves are to be located such that inadvertent or accidental operation is avoided.

8. Needle valves are not to be used as shut-off valves in the low-pressure side of the system. Gate valves are not to be used as shut-off valves.