(1)  All piping, tubing and fittings shall be made of material suitable for use in anhydrous ammonia service.

(2)  All piping, tubing, and fittings shall be designed for a pressure not less than the maximum pressure to which they may be subjected in service.

(3)  All piping shall be supported to prevent damage to the pipes. Provisions shall be made for expansion, contraction, jarring, vibration, and for settling. All refrigeration system piping shall conform to the Refrigeration Piping Code (ANSI B31.5)  as it applies to anhydrous ammonia.

(4)  Piping used on non-refrigerated systems shall be at least ASTM A-53 Grade B Electric Resistance Welded and Electric Flash Welded Pipe or equivalent. Such pipe shall be at least Schedule 40 when joints are welded, or welded and flanged. Such pipe shall be at least Schedule 80 when joints are threaded.

(5)  Metal, flexible connections may be used to provide for expansion, contraction, jarring, vibrating, and for settling. In no case shall the angle of the connection exceed 15 degrees. All such connections shall comply with the standards set forth in ANSI K 61.1, Section 2.7.5.

(6)  Cast iron fittings shall not be used, but this rule shall not prohibit the use of fittings made especially for anhydrous ammonia service of malleable or nodular iron, such as, Specification ASTM A 47 or ASTM A 395.

(7)  Provisions shall be made to protect all exposed piping from physical damage that might result from moving machinery, the presence of automobiles or trucks, or any other undue strain that may be placed upon the piping.

(8)  Joint compounds shall be compatible with anhydrous ammonia.

(9)  After assembly, all piping and tubing shall be tested and proven free of leaks at a pressure not less than the normal operating pressure of the system.

(10)  Connecting more than one storage tank to a single manifold line is prohibited unless the combined rated flow of the excess flow valves in all connected tanks does not exceed the maximum capacity of the main manifold line. Should the capacity of the line be reduced, excess flow valves of equal to or smaller capacity than the maximum capacity of the line are to be installed at the point of reduction.

History: Sec. 80-10-503, MCA; IMP, Sec. 80-10-503, MCA; NEW, 1986 MAR p. 1820, Eff. 10/31/86.