(a) The materials for piping systems must meet Sec. 154.625 for the minimum design temperature of the piping, except the material for open ended vent piping may be specially approved by the Commandant (CG-ENG) if:
(1) The temperature of the cargo at the pressure relief valve setting is -55 [deg]C (-67 [deg]F) or warmer; and
(2) Liquid cannot discharge to the vent piping.
(b) Materials for piping outside the cargo tanks must have a melting point of at least 925 [deg]C (1697 [deg]F), except for short lengths of pipes with fire resisting insulation that are attached to the cargo tanks. [CGD 74-289, 44 FR 26009, May 3, 1979, as amended by USCG-2014-0688, 79 FR 58285, Sept. 29, 2014]