154.522—Materials for piping.
(a)
The materials for piping systems must meet § 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-522) if:
(1)
The temperature of the cargo at the pressure relief valve setting is −55 °C (−67 °F) or warmer; and
(b)
Materials for piping outside the cargo tanks must have a melting point of at least 925 °C (1697 °F), except for short lengths of pipes with fire resisting insulation that are attached to the cargo tanks.