Material.

(a) Material used in the tank must be steel of good weldable quality and conform with the requirements in Sections V, VIII, and IX of the ASME Code (IBR, see § 171.7 of this subchapter). (b) The minimum thickness of metal, exclusive of lining material, for shell and heads of tanks shall be as follows: Tank capacity Minimum thickness (inch) Not more than 1,200 gallons 1 ⁄ 4 Over 1,200 to 1,800 gallons 5 ⁄ 16 Over 1,800 gallons 3 ⁄ 8 [29 FR 18972, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967, and amended by Amdt. 178-7, 34 FR 18250, Nov. 14, 1969; 68 FR 75750, Dec. 31, 2003]