49 C.F.R. § 179.300-8 Tank heads.
Title 49 - Transportation
(a) Class DOT-110A tanks shall have fusion-welded heads formed concave to pressure. Heads for fusion welding shall be an ellipsoid of revolution 2:1 ratio of major to minor axis. They shall be one piece, hot formed in one heat so as to provide a straight flange at least 1
where symbols are as defined in §179.300–6(a). (b) Class DOT-106A tanks must have forged-welded heads, formed convex to pressure. Heads for forge welding must be torispherical with an inside radius not greater than the inside diameter of the shell. They must be one piece, hot formed in one heat so as to provide a straight flange at least 4 inches long. They must have snug drive fit into the shell for forge welding. The wall thickness after forming must be sufficient to meet the test requirements of §179.300–16 and to provide for adequate threading of openings. [29 FR 18995, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967, and amended by Amdt. 179–10, 36 FR 21355, Nov. 6, 1971]
Title 49: Transportation
PART 179—SPECIFICATIONS FOR TANK CARS
Subpart E—Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW)
§ 179.300-8 Tank heads.
