§178.347-2 Material and thickness of material.

(a) The type and thickness of material for DOT 407 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). Tables I and II identify the specified minimum thickness values to be employed in that the 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 in gallons per inch	10 or less	Over 10 to 14	Over 14 to 18	Over 18 to 22	Over 22 to 26	Over 26 to 30	Over 30
Thickness (MS)	0.100	0.100	0.115	0.129	0.129	0.143	0.156
Thickness (HSLA)	0.100	0.100	0.115	0.129	0.129	0.143	0.156
Thickness (SS)	0.100	0.100	0.115	0.129	0.129	0.143	0.156
Thickness (AL)	0.160	0.160	0.173	0.187	0.194	0.216	0.237

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	Over 18 to 22	Over 22 to 26	Over 26 to 30	Over 30
Thickness (MS)	0.100	0.100	0.115	0.129	0.129	0.143	0.156
Thickness (HSLA)	0.100	0.100	0.115	0.129	0.129	0.143	0.156
Thickness (SS)	0.100	0.100	0.115	0.129	0.129	0.143	0.156
Thickness (AL)	0.151	0.151	0.160	0.173	0.194	0.216	0.237

(b) [Reserved]

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§178.347-2 Material and thickness of material.