{"operation":"document","citation":"49 CFR 179.200-8","title":"-8 Tank heads.","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 external tank heads must be an ellipsoid of revolution in which the major axis must equal the diameter of the shell and the minor axis must be one-half the major axis.\n\n(b) Internal compartment tank heads may be 2:1 ellipsoidal, 3:1 ellipsoidal, or flanged and dished to thicknesses as specif","machine_formats":{"json":"https://regulus.evalyn.ai/document/49-cfr-179-200-8.json","markdown":"https://regulus.evalyn.ai/document/49-cfr-179-200-8.md"},"app_url":"https://regulus.evalyn.ai/document/49-cfr-179-200-8","source_url":"https://www.ecfr.gov/on/2026-08-18/title-49/section-179.200-8","body":"(a) All external tank heads must be an ellipsoid of revolution in which the major axis must equal the diameter of the shell and the minor axis must be one-half the major axis.\n\n(b) Internal compartment tank heads may be 2:1 ellipsoidal, 3:1 ellipsoidal, or flanged and dished to thicknesses as specified in § 179.200-6. Flanged and dished heads must have main inside radius not exceeding 10 feet, and inside knuckle radius must not be less than 3 3/4 inches for steel, alloy steel, or nickel tanks, and not less than 5 inches for aluminum alloy tanks.\n\n[Amdt. 179-10, 36 FR 21350, Nov. 6, 1971]","truncated":false,"body_characters":594}