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 6 - Anhydrous Ammonia
Section 507 - Piping, Valves, and Fittings for Liquid and Vapor Lines
Current through Register 2024 Notice Reg. No. 38, September 20, 2024
(a) All pipe between the tank and first shutoff valve shall be at least Schedule 80.
All fittings between the tank and the first shutoff valve shall be steel as required by Section 507 (c), first paragraph.
Aboveground piping in excess of 1 1/2 -inch pipe size may be Schedule 40 when used beyond the first shutoff valve provided welded, or welded and flanged connections are used.
All other piping shall be Schedule 80.
All piping shall be tested after assembly and proved free of leaks at a pressure of not less than its normal operating pressure or 150 psi, whichever is greater.
Flammable material shall not be used for the installation acceptance pressure test.
All welded piping shall be fabricated and tested in accordance with the ANS Standards Code for Pressure Piping, Section 3, Petroleum Refinery Piping B-31.3, 1966 Edition or equivalent.
All refrigerated piping shall conform to the Refrigeration Piping Code, American National Standards Institute, B-31.5-1966 with addenda B-31.1a-1968 as it applies to ammonia.
Hose shall not be used in lieu of piping between the tank and loading and/or unloading connection, except that a section of metallic hose, not to exceed 24 inches in length may be used in each pipeline to provide flexibility and except as provided in Section 504 (j). The manufacturer's identification required in Section 510 (b) shall be retained on each section.
(b) All piping shall run as directly as practical, with suitable provision for expansion, contraction, jarring, vibrations, and settling. Piping may be either buried or installed aboveground, and shall be well supported and protected against physical damage. All underground piping shall be buried not less than 18 inches below the surface of the ground unless otherwise protected, and shall be adequately coated or otherwise protected against corrosion. Pipe coated as follows will be considered acceptable:
Equivalent wrapping will be accepted at the discretion of the Division.
(c) All steel fittings used with Schedule 80 pipe shall be Schedule 80 if butt welded, 3,000 pound WOG if socket welded, and 2,000 pound WOG forged steel if threaded.
All other steel fittings shall have a rating of at least Schedule 40 if butt welded and 2,000 pound WOG if socket welded or threaded. Threaded connections shall not be seal welded.
Joint compounds shall be resistant to ammonia.
All other valves and fittings shall be of a type suitable for use with anhydrous ammonia and shall have a pressure rating of at least 400 psi WOG. Valve seat material, packing, gaskets, etc., shall be suitable for anhydrous ammonia service.
(d) The use of the following is prohibited:
Cast iron fittings made specifically for anhydrous ammonia service, meeting ASTM A-126-66, class B or C, may be used for secondary service if they have a service rating of at least 600 psi.
(e) Except for service valves, safety relief valves, and gaging connections, all liquid and vapor connections shall have 1 of the following installed directly in the tank connections:
Excess flow valves shall be designed with a bypass, not to exceed a No. 60 drill-size opening to allow equalization of pressures.
All excess flow valves shall be plainly and permanently marked with the name or trademark of the manufacturer, the catalog number, and the rated capacity.
NOTE: Service valve as used in this order is limited to vapor valves screwed into vessel outlets not larger than 3/4 -inch pipe size and having an inlet internal diameter in the valve body not exceeding the internal diameter of a 1/2 -inch Schedule 80 pipe.
(f) In addition to the valves required in Section 507 (e), all liquid and vapor connections other than safety relief valve and gaging connections shall be fitted with a manually operated shutoff valve located:
When a pump is attached directly to a valve complying with Section 507 (e)(1)(D) or (E), the manually operated shutoff valve required by this Order may be located between said pump and the meter or bulkhead, whichever is nearest the tank.
(g) Every liquid pipeline or hose that can be isolated by 2 or more stop valves shall have a safety relief valve installed in the pipeline or hose to prevent excessive hydrostatic pressure. The safety relief valve required by this subsection shall start to discharge at not less than 300 psi, nor more than 400 psi, and it must relieve to the atmosphere at a safe point of discharge.
(h) All valves, regulators, gaging, and other tank accessory equipment shall be protected against physical damage.
(i) All tank connections requiring manually operated shutoff valves shall be labeled or tagged to indicate whether they communicate with the liquid or vapor space.
(j) The liquid fill line used to transfer anhydrous ammonia from transportation tanks exceeding 3,500 gallons capacity to storage tanks exceeding 2,000 gallons capacity shall be equipped with a backflow check valve to prevent discharge of anhydrous ammonia from the receiving tank in case of hose rupture. This is not intended to prevent transferring anhydrous ammonia from containers, other than transportation tanks exceeding 3,500 gallons capacity, into storage tanks through the load-out line.
(k) All tanks shall be equipped with vapor return valves.
1. Amendment filed 12-8-72 as procedural and organizational; effective upon filing (Register 72, No. 50).
2. Repealer of subsection (e) and new subsection (e) filed 8-30-74; effective thirtieth day thereafter (Register 74, No. 35).
3. Amendment of subsections (a), (c), (d), (e), (g) and new subsection (k) filed 3-28-75; effective thirtieth day thereafter (Register 75, No. 13).
4. Repealer and new subsections (e) and (f) filed 8-6-76; effective thirtieth day thereafter (Register 76, No. 32).