(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
(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
(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.