California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 1 - Unfired Pressure Vessel Safety Orders › Article 7 - Compressed and Liquefied Natural Gas System › Section 536 - Piping Standards

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) General.
(1) All pipe, tubing, fittings and other
					 piping components between the tank and the first shutoff valve shall be
					 designed for the full range of pressures, temperatures and loadings to which
					 they may be subjected with a factor of safety of at least 8 based on the
					 minimum specified tensile strength at room temperature. All other pipe, tubing,
					 fittings and other piping components shall be suitable for the full range of
					 pressures, temperatures and loadings to which they may be subjected with a
					 factor of safety of at least 4. In no case may underground piping be less than
					 Schedule 80 for piping systems having a working pressure exceeding 100 psi. Any
					 material used, including gaskets and packing, shall be compatible with natural
					 gas and its service conditions.
(2)
					 All piping and tubing shall be run as directly as practical with adequate
					 provisions for expansion, contraction, jarring, vibration and settling.
					 Exterior piping may be either buried or installed aboveground and shall be well
					 supported and protected against mechanical damage.
Underground piping shall be buried not less than 18
						inches below the surface of the ground unless otherwise protected. All
						underground piping shall be protected from corrosion by coating in compliance
						with Section
						533 (b) or
						equivalent. Zinc coatings (galvanizing) shall not be considered adequate
						protection for piping below ground.
(3) All welded piping shall be fabricated and
					 tested in accordance with the ANSI Code for Pressure Piping, Petroleum Refinery
					 Piping, B31.3, 1966 Edition or equivalent.
(4) All valves shall be suitable for the full
					 range of pressure and temperature to which they may be subjected. The
					 manufacturer shall stamp or otherwise permanently mark the valve body to
					 indicate the service ratings. Other piping components such as strainers,
					 snubbers and expansion joints shall also be permanently marked by the
					 manufacturer to indicate the service ratings. All materials such as valve
					 seats, packing, gaskets, diaphragms, etc. shall be resistant to the action of
					 natural gas under the conditions to which they are subjected.
(5) Use of the following is prohibited:
(A) Valves, cocks, fittings and other piping
					 components of cast iron or semisteel other than ASTM Specifications A-536-67,
					 Grade 60-40-18; A-395-68; A-47-68, Grade 35018 and A-445-66 unless they have
					 pressure-temperature ratings at least equal to 1 ½ times the design
					 service conditions. In no case shall valves of cast iron or semisteel other
					 than the 3 ASTM specifications listed above be used for primary stop
					 valves.
(B) Street ells and screwed
					 service tees.
(C) Valves of a
					 design that will allow the valve stem to be removed without removal of complete
					 valve bonnet or disassembly of the valve body.
(D) Plastic pipe, tubing, hose and fittings,
					 without written permission from the Division.
(E) Valves with valve stem packing glands
					 which cannot be repacked under pressure, unless there is another stop valve of
					 acceptable type between them and the vessel. This does not apply to service
					 valves.
(F) Aluminum tubing for
					 exterior locations and threaded aluminum connections and adapters that are
					 required to be connected or disconnected as part of the filling or transferring
					 operation except for those connections and adapters that are specifically
					 designed with special threads suitable for this service.
(G) Pipe nipples in lieu of couplings or
					 flanges in tank connections.
(H)
					 Copper alloy with copper content exceeding 70
					 percent.