{"operation":"document","citation":"49 CFR 179.200-21","title":"-21 Closures for openings.","source_type":"regulation","agency":"Pipeline and Hazardous Materials Safety Administration","status":"current","official":true,"published_on":null,"effective_on":"2026-08-18","summary":"(a) All plugs shall be solid, with NPT threads, and shall be of a length which will screw at least 6 threads inside the face of fitting or tank. Plugs, when inserted from the outside of tank heads, shall have the letter “S” at least 3/8 inch in size stamped with steel stamp or cast on the outside su","machine_formats":{"json":"https://regulus.evalyn.ai/document/49-cfr-179-200-21.json","markdown":"https://regulus.evalyn.ai/document/49-cfr-179-200-21.md"},"app_url":"https://regulus.evalyn.ai/document/49-cfr-179-200-21","source_url":"https://www.ecfr.gov/on/2026-08-18/title-49/section-179.200-21","body":"(a) All plugs shall be solid, with NPT threads, and shall be of a length which will screw at least 6 threads inside the face of fitting or tank. Plugs, when inserted from the outside of tank heads, shall have the letter “S” at least 3/8 inch in size stamped with steel stamp or cast on the outside surface to indicate the plug is solid.\n\n(b) [Reserved]","truncated":false,"body_characters":352}