Section 5 Piping requirements

5.1.1 Regasification system piping shall meet the applicable requirements of Ch 5 Process Pressure Vessels and Liquid, Vapour and Pressure Piping Systems of the Rules for Ships for Liquefied Gases and Pt 5, Pt 5, Ch 12 Piping Design Requirements, Pt 5, Ch 13 Ship Piping Systems and Pt 5, Ch 14 Machinery Piping Systems of the Rules for Ships.

5.1.2 All piping, valves and fittings shall be suitable for the operating and environmental conditions.

5.2.1 All materials used in the piping systems shall be suitable for use with the intended medium, service and ambient conditions, and shall comply with the applicable requirements of Chapter 6 of the Rules for Ships for Liquefied Gases and of Pt 5, Ch 12 Piping Design Requirements of the Rules for Ships.

5.3.1 Piping between the LNG ship cargo system and the regasification system shall be equipped with a manually operated stop valve and a remotely controlled emergency shut-down valve. These valves shall be located as close to the tank as practicable. When the regasification unit is located in the forward section of the ship, such isolation shall be as near as possible to the boundary of the forwardmost cargo tank bulkhead and within the cargo area.

5.3.2 Dry break quick-release connectors shall be provided for use in an emergency in:

1. piping between an LNG supply ship and the regasification system;

2. send-out gas piping between a regasification ship and receiving terminal.

5.3.3 A manually operated shut-off terminal valve shall be provided at the send-out manifold, in addition to any other automatic shut-off valves required by the Rules for Ships for Liquefied Gases.

5.3.4 The spool piece, reducers, valves and other fittings to which the cargo system or the send-out system is directly connected shall be of approved material. They shall be of robust construction, adequately supported and suitable for the stated design conditions and manifold forces. For LNG transfer, attention is drawn to SIGTTO ‘Manifold Recommendations for Liquefied Gas Carriers’.

5.3.5 Means of purging, inerting and gas-freeing the pipe lines used for the regasification system shall be provided.

5.3.6 Means for mechanical separation shall be provided between the regasification piping system and the ship’s inert gas and nitrogen systems.

5.3.7 All main isolating valves serving the regasification systems and equipment shall be located in a readily accessible location.

5.3.8 The fabrication and installation of the piping associated with the regasification system and its ancillary systems shall be in accordance with the relevant Sections of the Rules for Ships and the Rules for Ships for Liquefied Gases to the satisfaction of the Surveyor.

5.3.9 Provisions shall be incorporated in the design to minimise the number of flanged connections. In order to protect personnel from cryogenic burns and prevent ship structure or other carbon steel structures on deck from being exposed to brittle fracture due to LNG pressure jet, consideration shall be given to the fitting of spray shield arrangements to any flanged connection of piping containing LNG at a pressure above 10 bar.

5.3.10 Where applicable, all LNG pipework servicing the regasification system shall be suitably insulated and shall be covered with an efficient vapour barrier.

5.3.11 All low and high pressure LNG supply pipework serving the regasification systems is to be subject to a stress analysis, taking into account all the stresses due to weight of pipes, including acceleration loads if significant, internal pressure, thermal contraction and loads induced by hog and sag of the ship for each branch of the piping system.

5.4.1 Testing and non-destructive examination of the regasification unit, LNG and gas piping systems shall comply with the relevant requirements of Pt 5, Ch 12, 9 Piping for LPG/LNG carriers, gas fuelled ships and classed refrigeration systems of the Rules for Ships and Ch 5 Process Pressure Vessels and Liquid, Vapour and Pressure Piping Systems of the Rules for Ships for Liquefied Gases.

5.4.2 All piping systems shall be subjected to a hydrostatic test to at least 1,5 times the design pressure. When piping systems or parts of systems are completely manufactured and equipped with all fittings, the hydrostatic test may be conducted prior to installation aboard ship. Joints welded on board shall be hydrostatically tested to at least 1,5 times the design pressure. Where water cannot be tolerated or the piping cannot be dried prior to putting the system into service, proposals for alternative testing fluids or testing means shall be submitted for special consideration by the Surveyor.

5.4.3 After assembly on board, all cargo and process piping shall be subjected to a leak test using air, halides or other suitable medium to a pressure dependant on the leak detection method applied.

5.4.4 All piping systems including valves, fittings and associated equipment for handling cargo or vapours shall be tested under normal operating conditions not later than at the first regasification operation.