{"data":{"id":"us/46-cfr-154.524","jurisdiction":"us","citation":"46 CFR 154.524","heading":"Piping joints: Welded and screwed couplings.","body":"Pipe lengths without flanges must be joined by one of the following:\n(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:\n(1) A backing ring that for design pressures greater than 979 kPa gauge (142 psig) must be removed after the weld is completed;\n(2) A consumable insert; or\n(3) An inert gas back-up on the first weld pass.\n(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.\n(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.\n(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.\n(e) A method or fitting specially approved by the Commandant (CG-ENG).","path":["Title 46—Shipping","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER O—CERTAIN BULK DANGEROUS CARGOES","PART 154—SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES","Subpart C—Design, Construction and Equipment"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-46.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:22Z","sha256":"d4c22aacf4ba80a25c098d45ef548a5fb743165c0848d3d69c7645545450c441","source_id":"us-cfr","stale":true,"prev":"us/46-cfr-154.522","next":"us/46-cfr-154.526"},"notice":"GroundRules: Original legal text. Not legal advice."}