{"data":{"id":"us/49-cfr-179.200-8","jurisdiction":"us","citation":"49 CFR 179.200-8","heading":"-8 Tank heads.","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(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.","path":["Title 49—Transportation","Subtitle B—Other Regulations Relating to Transportation","CHAPTER I—PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","SUBCHAPTER C—HAZARDOUS MATERIALS REGULATIONS","PART 179—SPECIFICATIONS FOR TANK CARS","Subpart D—Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW, 115AW, and 117AW)"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-49.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:34Z","sha256":"67244dc27e52ee5108d88cbcd6a5c7df802798bb6a7bb838ae5e1e84372cb738","source_id":"us-cfr","stale":true,"prev":"us/49-cfr-179.200-7","next":"us/49-cfr-179.200-9"},"notice":"GroundRules: Original legal text. Not legal advice."}