46 CFR §56.10-5

1. (a)General. Pipe and tubing must be selected as described in table 1 to § 56.60-1.
2. (b)Ferrous pipe. ASTM A53/A53M (incorporated by reference, see § 56.01-2) furnace welded pipe must not be used for combustible or flammable liquids within machinery spaces. (See §§ 30.10-15 and 30.10-22 of this chapter for definitions of combustible and flammable liquids.)
3. (c)Nonferrous pipe. (See also § 56.60-20.)
   1. (1)Copper and brass pipe for water and steam service may be used for design pressures up to 250 psig and for design temperatures to 406 °F.
   2. (2)Copper and brass pipe for air may be used in accordance with the allowable stresses of the materials found from table 1 to § 56.60-1.
   3. (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 § 56.01-2).
   4. (4)Copper tubing may be used for instrument service up to 1,000 psig.
   5. (5)Copper, brass, or aluminum pipe or tube must not be used for flammable fluids except where specifically permitted by this part.
   6. (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.
4. (d)Nonmetallic pipe. Plastic pipe may be used subject to the conditions described in § 56.60-25.