CFR > Title 49 - Transportation > SUBTITLE B—Other Regulations Relating to Transportation > CHAPTER I—PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (Parts 105–199) > SUBCHAPTER C—HAZARDOUS MATERIALS REGULATIONS (Parts 171–181) > PART 178—SPECIFICATIONS FOR PACKAGINGS > SUBPART J—Specifications for Containers for Motor Vehicle Transportation (§178.318 to §178.348-5) > 178.348-2—Material and thickness of material.

178.348-2—Material and thickness of material.

(a) The type and thickness of material for DOT 412 specification cargo tanks must conform to § 178.345-2, but in no case may the thickness be less than that determined by the minimum thickness requirements in § 178.320(a). The following Tables I and II identify the “Specified Minimum Thickness” values to be employed in that determination.
Table I—Specified Minimum Thickness of Heads (or Bulkheads and Baffles When Used as Tank Reinforcement) Using Mild Steel (MS), High Strength Low Alloy Steel (HSLA), Austenitic Stainless Steel (SS), or Aluminum (AL)—Expressed in Decimals of an Inch After Forming
Volume capacity (gallons per inch) 10 or less Over 10 to 14 Over 14 to 18 18 and over
Lading density at 60 °F in pounds per gallon 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs Over 16 lbs 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs Over 16 lbs 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs
Thickness (inch), steel .100 .129 .157 .187 .129 .157 .187 .250 .157 .250 .250 .157 .250 .312
Thickness (inch), aluminum .144 .187 .227 .270 .187 .227 .270 .360 .227 .360 .360 .227 .360 .450
Table II—Specified Minimum Thickness of Shell Using Mild Steel (MS), High Strength Low Alloy Steel (HSLA), Austenitic Stainless Steel (SS), or Aluminum (AL)—Expressed in Decimals of an Inch After Forming
Volume capacity in gallons per inch 10 or less Over 10 to 14 Over 14 to 18 18 and over
Lading density at 60 °F in pounds per gallon 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs Over 16 lbs 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs Over 16 lbs 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs 10 lbs and less Over 10 to 13 lbs Over 13 to 16 lbs
Thickness (steel):
Distances between heads (and bulkheads baffles and ring stiffeners when used as tank reinforcement):
36 in. or less .100 .129 .157 .187 .100 .129 .157 .187 .100 .129 .157 .129 .157 .187
Over 36 in. to 54 inches .100 .129 .157 .187 .100 .129 .157 .187 .129 .157 .187 .157 .250 .250
Over 54 in. to 60 inches .100 .129 .157 .187 .129 .157 .187 .250 .157 .250 .250 .187 .250 .312
Thickness (aluminum):
Distances between heads (and bulkheads baffles and ring stiffeners when used as tank reinforcement):
36 in. or less .144 .187 .227 .270 .144 .187 .227 .270 .144 .187 .227 .187 .227 .270
Over 36 in. to 54 inches .144 .187 .227 .270 .144 .187 .227 .270 .187 .227 .270 .157 .360 .360
Over 54 in. to 60 inches .144 .187 .227 .270 .187 .227 .270 .360 .227 .360 .360 .270 .360 .450
(b) [Reserved]
[Amdt. 178-89, 54 FR 25031, June 12, 1989; 54 FR 28750, July 7, 1989, as amended at 55 FR 37065, Sept. 7, 1990; 68 FR 19285, Apr. 18, 2003]