49 CFR §179.300-14
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Siphon pipes and their couplings on the inside of the tank head and lugs on the outside of the tank head for attaching the valve protective housing must be fusion-welded in place prior to postweld heat treatment. All other fixtures and appurtenances, except as specifically provided for, are prohibited.