Section 5 Piping requirements

5.1 General

5.1.1 Regasification system piping shall meet the applicable requirements of Pt 11, Ch 5 Process Pressure Vessels and Liquids, Vapour and Pressure Piping Systems and Offshore Arrangements and Pt 5, Ch 12 Piping Design Requirements, Pt 5, Ch 13 Bilge and Ballast Piping Systems and Pt 5, Ch 14 Machinery Piping Systems.

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

5.2 Materials

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 Pt 11, Ch 6 Materials of Construction and Quality Control and Pt 5, Ch 12 Piping Design Requirements.

5.3 Piping design

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

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

piping between an LNG supply ship and the barge of offshore unit;
send-out gas piping between the barge or offshore unit 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, see Pt 11, Ch 20, 4.4 Emergency shutdown (ESD) system and Pt 11, Ch 20, 4.5 Process shutdown (PSD) system.

5.3.4 The spool piece, reducers, valves and other fittings to which the LNG storage 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 draining, purging, inerting and gas-freeing the pipe lines used for the regasification system shall be provided.

5.3.6 Means of mechanical separation shall be provided between the regasification piping system and the barge or offshore unit’s inert gas and nitrogen systems.

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

5.3.8 The fabrication and installation of the piping associated with the regasification plant and sub-systems shall be in accordance with the relevant Sections of these Rules.

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 the barge or offshore unit’s 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 g.

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

5.3.11 Both low and high pressure LNG supply pipework serving the regasification systems is to be subject to a stress analysis, taking into account ship motions and deflections.

5.4 Piping system testing and non-destructive examination

5.4.1 Testing and non-destructive examination of the regasification unit’s LNG supply and gas discharge piping systems shall comply with the relevant requirements of Pt 11, Ch 5 Process Pressure Vessels and Liquids, Vapour and Pressure Piping Systems and Offshore Arrangements and Pt 5, Ch 12 Piping Design Requirements.

5.4.2 All piping systems shall be subjected to a hydrostatic test in accordance with Pt 11, Ch 20, 5.4 Piping system testing and non-destructive examination 5.4.2 Pt 11, Ch 20, 5 Piping requirements. When piping systems or parts of systems are completely manufactured and equipped with all fittings, the hydrostatic test may be conducted prior to installation on board the barge or offshore unit. Joints welded on board shall be hydrostatically tested in accordance with Pt 11, Ch 20, 5.4 Piping system testing and non-destructive examination 5.4.2. 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.

Table 20.5.1 Strength and leak pressure testing

System	Test pressure, bar g
System	Strength test	Leakage test
LNG and NG below 40 bar g	1,5 p	See Pt 11, Ch 20, 5.4 Piping system testing and non-destructive examination 5.4.3
LNG and NG at and above 40 bar g.	1,25 p	See Pt 11, Ch 20, 5.4 Piping system testing and non-destructive examination 5.4.3
NOTE p is the design pressure which is the maximum permissible pressure within the system (or part system) in operation or at rest.

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 dependent 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 prior to the first regasification operation.