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

Interpretation Response #01-0305 ([Federal Motor Carrier Safety Administration] [William A. Quade])

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

Interpretation Response Details

Response Publish Date:

Company Name: Federal Motor Carrier Safety Administration

Individual Name: William A. Quade

Location State: DC Country: US

View the Interpretation Document

Response text:

Date:    MAY 10, 2001               Reply to Attn of Gorsky, x69532          Ref. No. 01-01305

Subject:     Pressure Testing of Cargo Tanks

From:    Thomas G. Allan
Senior Transportation Regulations Specialist
Office of Hazardous Materials Standards

To:    William A. Quade
Chief of Hazardous Materials Division
Federal Motor Carrier Safety Administration

This responds to your request for an interpretation, bye-mail dated May 2, 2001, related to pressure testing Me 306 and DOT 406 specification cargo tanks under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask whether a manhole cover must be removed and replaced with a blank flange for the pressure test.

Your e-mail describes a manhole that includes a fill opening and pressure relief vent as one piece. Apparently, some manhole manufacturers are advising cargo tank operators to remove the manhole/fill opening/pressure relief vent component and replace it with a blank flange for the cargo tank's pressure test.

Section 180.407(g) requires all components of a cargo tank wall to be pressure tested. The cargo tank wall includes those parts of the cargo tank that make up the primary lading retention structure, including shell, bulkheads, and fittings, which, when closed during transportation, yield the minimum volume of the cargo tank assembly (see § 178.320(a». A manhole cover is part of the cargo tank wall. Under the pressure test procedure outlined in § 180.407(g), the manhole/fill opening/pressure relief component should be removed from the cargo tank so that the pressure relief vent can be bench tested (see § 180.407(g)(1)(ii)(A)). Since § 180.407(g)(I)(vii) requires the pressure test of the cargo tank to be conducted with all closures (except pressure relief devices) in place, the manhole/fill opening/pressure relief component should then be reinstalled and the pressure relief device disabled for the pressure test. You are correct that removing the manhole/fill opening/pressure relief component and replacing it with a blank flange for the pressure test is not consistent with the pressure test procedure in § 180.407(g).

I hope this information is helpful. If you have further questions, please do not hesitate to contact this office.

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180.407

Regulation Sections

Section Subject
180.407 Requirements for test and inspection of specification cargo tanks