USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #21-0020

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Transport Canada, Ontario Region

Individual Name: Brent Grice

Location State: ON Country: CA

View the Interpretation Document

Response text:

October 22, 2021

Mr. Brent Grice
Dangerous Goods Inspector
Transport Canada, Ontario Region
4900 Yonge Street-3rd Floor
North York, Ontario  M2N 6A5
Canada

Reference No. 21-0020

Dear Mr. Grice:

This letter is in response to your March 2, 2021, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to rejection criteria during the inspection of Department of Transportation (DOT) Specification 51 portable tanks.

We have paraphrased and answered your questions as follows:

Q1. You ask what the rejection criteria is for a DOT Specification 51 portable tank should a reduction in wall thickness be found during an inspection.

A1. If a DOT Specification 51 portable tank is found to have a reduction in wall thickness during an inspection and it is verified by appropriate measurement, the wall thickness may not fall below the minimum thickness (i.e., the manufactured thickness minus any applicable corrosion allowance). If it does, the inspector may determine such findings to be evidence of an "unsafe condition."

Q2. You ask how a person should determine the minimum thickness of a DOT Specification 51 portable tank since the minimum thickness is not required to be marked on the name plate.

A2. If a DOT Specification 51 portable tank is not marked with the minimum wall thickness, the thickness listed on the manufacturer's data report—minus any applicable corrosion allowance—may be used as the minimum thickness of the portable tank.

Q3. You ask whether thickness readings that are below the thicknesses indicated on the manufacturer's data report—minus any applicable corrosion allowance—meet the rejection criteria of § 180.605(i) as evidence of an "unsafe condition."

A3. The answer is yes. If thickness readings are below the thicknesses indicated on the manufacturer's data report—minus any applicable corrosion allowance—the inspector may determine such findings to be evidence of an "unsafe condition" in accordance with § 180.605(i). See answer A1.

I hope this information is helpful. Please contact us if we can be of further assistance.

Sincerely,

T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

180.605(i)

Regulation Sections