46 C.F.R. § 154.524 Piping joints: Welded and screwed couplings.
Title 46 - Shipping
Pipe lengths without flanges must be joined by one of the following: (a) A butt welded joint with complete penetration at the weld root except that for design temperatures colder than −10 °C (14 °F) the butt weld must be double welded or must be welded using: (1) A backing ring that for design pressures greater than 979 kPa gauge (142 psig) must be removed after the weld is completed; (2) A consumable insert; or (3) An inert gas back-up on the first weld pass. (b) A slip-on welded joint with sleeves and attachment welds is allowed for an open ended pipe with an external diameter of 50 mm (2 in.) or less and a design temperature of −55 °C (−67 °F), or warmer. (c) A socket weld fitting with attachment welds is allowed for pipe with an external diameter of 50 mm (2 in.) or less and a design temperature of −55 °C (−67 °F) or warmer. (d) Screwed couplings are allowed for instrumentation and control piping that meets §56.30–20 and §56.50–105 (a)(4) and (b)(4) of this chapter. (e) A method or fitting specially approved by the Commandant (G-MSO). [CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
Title 46: Shipping
PART 154—SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES
Subpart C—Design, Construction and Equipment
Cargo and Process Piping Systems
§ 154.524 Piping joints: Welded and screwed couplings.
