This information is provided free of charge by the Department of Industrial Relations from its web site at These regulations are for the convenience of the user and no representation or warranty is made that the information is current or accurate. See full disclaimer at

Subchapter 1. Unfired Pressure Vessel Safety Orders
Article 5. LP-Gas Systems.

Return to index
New query

§480. Pipes and Fittings for All Liquid Lines and for Vapor Lines Where the Pressure Exceeds 20 PSI.

(a) All pipe between the container and first shutoff valve shall be Schedule 80 (extra heavy). All fittings between the container and first shutoff valve shall be steel as required by Section 480(c).

Aboveground piping in excess of 1 1/2 inch pipe size may be Schedule 40 when used beyond the first shutoff valve, providing:

(1) Threaded connections are used and the piping is used for vapor service only at less than 125 psi.

(2) Welded connections are used and the piping is used for liquid or vapor service at less than 400 psi.

All other piping shall be Schedule 80.

Where used, flare nuts shall be of forged brass.

All welded piping shall be fabricated and tested in accordance with the ANSI Standard Code for Pressure Piping, Section 3, Petroleum Refinery Piping B-31.3, 1993 Edition or equivalent.

(b) Piping outside of buildings may be either buried or installed aboveground and shall be well-supported and protected against mechanical injury. All underground piping shall be Schedule 80 and shall be buried not less than 18 inches below the surface of the ground, unless otherwise protected, and shall be protected from corrosion by approved corrosion-resistant material and by cathodic protection.

Voltage readings from the cathodic system shall be taken and recorded annually and shall produce a negative voltage of at least 0.85 volts with reference to a saturated copper-copper sulfide half-cell. Where impressed current is used, amperage and voltage readings shall be recorded at 6-month intervals.

(c) All steel fittings used with Schedule 80 pipe shall be Schedule 80 if butt welded, 3,000 pounds WOG if socket welded, and 2,000 pounds WOG forged steel if threaded. All other steel fittings shall have a rating of at least Schedule 40 if butt welded, and 2,000 pounds WOG if socket welded or threaded.

All steel valves and fittings shall have a steam rating of at least one hundred fifty (150) psi, ANSI standard, with a minimum WOG rating of 250 psi. Valves of material other than steel shall have a pressure rating of at least two hundred (200) psi steam, or four hundred (400) psi WOG. The manufacturer of LP-Gas valves shall stamp or otherwise permanently mark the valve body to indicate the pressure rating. Steam valves when used for LP-Gas service shall be refitted for such service. Valve seat material, packing, gaskets, etc., shall be resistant to the action of LP-Gas.

(d) The use of the following is prohibited:

(1) Valves of a design that will allow the valve stem to be removed without removal of complete valve bonnet.

(2) Valves with valve stem packing glands which cannot be repacked under pressure, unless there is another valve of acceptable type between them and the tank.

(3) Aluminum tubing.

(4) Pipe nipples used in lieu of couplings or flanges on tanks.

(5) Multivalves without excess-flow valves and fixed dip tubes for use other than DOT cylinders.

(e) In addition to the valves required in NFPA 58, Section 2-3.3.2, all liquid and vapor connections shall be fitted with manually operated shutoff valves located as close to the container as practicable.

(f) Where containers are in liquid service or a combination of liquid and vapor service, all connections with manually operated shutoff valves shall be legibly labeled to indicate whether they communicate with the vapor or liquid space.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 13241, Health and Safety Code.


1. Amendment filed 4-1-77; effective thirtieth day thereafter (Register 77, No. 14). For prior history, see Register 75, No. 45.

2. Amendment of section, including repealer of table 480, and new Note filed 12-4-96; operative 1-3-97 (Register 96, No. 49).

Go BackGo Back to Article 5 Table of Contents