178.255-2 Material.§ 178.255-2 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|