Minimum Thickness for Metal Drums or Jerricans
Pipeline and Hazardous Materials Safety Administration · Jan 6, 1995 · Reference No. 95-0185
Interprets: 49 CFR § 171.10, 49 CFR § 173.28
Reggie’s quick take
A reader asked whether the 0.03-inch figure for reusing metal drums or jerricans is the required minimum thickness. The agency said no. Under § 171.10(a), the metric figure is the regulatory standard, so the minimum is 0.80 mm. The inch figure in parentheses is only for information. A more precise U.S. equivalent is 0.0315 inches.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your August 2, 1994 letter concerning the minimum thickness of steel prescribed for reuse of metal drums. You indicated that footnote 1 of 49 CFR 173.28(b)(4) authorizes a minimum thickness of 0.8 mm for metal drums or jerricans, which is rounded to a U.S. customary equivalent of 0.03 inches.
You are correct that the footnote to § 173.28(b)(4) authorizes a minimum thickness of 0.80 mm for metal drums or jerricans. As specified in § 171.10(a), the SI (metric) unit is the regulatory standard. A U.S. standard or customary unit appearing in parentheses following the SI unit is provided for information only and is not intended to be the regulatory standard. Therefore, 0.80 mm, not 0.03 inches is the required minimum thickness for metal drums or jerricans. Using the conversion factor in § 171.10(c) for thickness, a more precise U.S. standard measure would be 0.0315 inches.
I hope this information is helpful. If you require additional assistance please contact this office.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.