46 CFR 56.10-5 - Pipe.
(a) General. Pipe and tubing shall be selected as described in table 56.60-1(a).
(b) Ferrous pipe. ASTM Specification A 53 (incorporated by reference, see § 56.01-2) furnace welded pipe shall not be used for combustible or flammable liquids within machinery spaces. (See §§ 30.10-15 and 30.10-22 of this chapter.)
(c) Nonferrous pipe. (See also § 56.60-20.) (1) Copper and brass pipe for water and steam service may be used for design pressures up to 250 pounds per square inch and for design temperatures to 406 °F.
(2) Copper and brass pipe for air may be used in accordance with the allowable stresses found from table 56.60-1(a).
(3) Copper-nickel alloys may be used for water and steam service within the design limits of stress and temperature indicated in ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2).
(4) Copper tubing may be used for dead-end instrument service up to 1,000 pounds per square inch.
(5) Copper, brass, or aluminum pipe or tube shall not be used for flammable fluids except where specifically permitted by this part.
(6) Aluminum-alloy pipe or tube along with similar junction equipment may be used within the limitation stated in 124.7 of ASME B31.1 and paragraph (c)(5) of this section.
(d) Nonmetallic pipe. Plastic pipe may be used subject to the conditions described in § 56.60-25.