PDFWAC 296-307-40021

Piping, tubing, and fittings.

(1) All piping, tubing and fittings must be made of material suitable for anhydrous ammonia service.
(2) All piping, tubing and fittings must be designed for a pressure of at least the maximum pressure to which they may be subjected in service.
(3) All piping must be well supported and allow for expansion and contraction. All refrigeration system piping must conform to the Refrigeration Piping Code (ANSI B31.5 1966 addenda B31.1a-1968), a section of the American Standard Code for Pressure Piping, as it applies to ammonia.
(4) Piping used on nonrefrigerated systems must meet the requirements of ASTM A-53-1969 Grade B Electric Resistance Welded and Electric Flash Welded Pipe. Pipe must be at least Schedule 40 when joints are welded, or welded and flanged. Pipe must be at least Schedule 80 when joints are threaded. Brass, copper, or galvanized steel pipe or tubing is prohibited.
(5) All metal flexible connections for permanent installations must have a minimum working pressure of 250 psig (safety factor of 4). For temporary installations, the employer may use hose that meets the requirements of WAC 296-307-40023.
(6) Cast iron fittings are prohibited. The employer must use fittings made especially for ammonia service of malleable or nodular iron that meet the requirements of Specification ASTM A47 or ASTM A395.
(7) All piping, tubing, and fittings must allow for expansion, contraction, jarring, vibration, and settling.
(8) The employer must make adequate provision to protect all exposed piping from physical damage from moving machinery, the presence of automobiles or trucks, or other strain on the piping.
(9) Joint compounds must be resistant to ammonia.
(10) After assembly, all piping and tubing must be tested and proved to be free from leaks at pressure that is at least equal to the normal operating pressure of the system.
[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, and 49.17.060. WSR 20-21-091, § 296-307-40021, filed 10/20/20, effective 11/20/20. Statutory Authority: RCW 49.17.040. WSR 98-24-096, § 296-307-40021, filed 12/1/98, effective 3/1/99. WSR 97-09-013, recodified as § 296-307-40021, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040, [49.17.]050 and [49.17.]060. WSR 96-22-048, § 296-306A-40021, filed 10/31/96, effective 12/1/96.]