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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 #00-0157 ([Mr. John P. McGavis] [Mr. John P. McGavis])

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

Interpretation Response Details

Response Publish Date:

Company Name: Mr. John P. McGavis

Individual Name: Mr. John P. McGavis

Location State: NY Country: US

View the Interpretation Document

Response text:

June 21, 2000

Mr. John P. McGavis                                             Ref.  No. 00-0157

Specialized Transport Repair, Inc.

100 Commerce Drive

Buffalo, New York 14218

Dear Mr. McGavis:

This is in further response to your letter, dated May 25, 2000, concerning cargo tank retest requirements under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).  You asked whether an MC 307 cargo tank on which the manway cover has been altered by the addition of a 3" nozzle must complete a pressure test before it can be returned to service.

After further discussion with technical staff of the Research and Special Programs Administration's Office of Hazardous Materials Technology and the Federal Motor Carrier Safety Administration's Hazardous Materials Division, we have determined that your previous response to your question, in our letter dated June 7, 2000, was in error.  The addition of a 3" nozzle to a Manway cover is, in fact, a 11 modification to the cargo tank because it involves a change to the design and construction of the cargo tank that affects its lading retention capability (see § 180.403 ofth6 HMR), Thus, a Design Certifying Engineer must certify that the modified design for the manhole assembly meets the structural integrity requirements of the DOT 407 specification, and a Registered Inspector must certify that the modified manhole assembly conforms to the DOT 407 specification by issuing a supplemental manufacturer's certificate (see §180.413(d)(5)). The modified manhole assembly must conform to the requirements for the DOT 407 cargo tank specification in §178.345-5.

In addition, the suitability of a modification that affects the structural integrity of a cargo tank with respect to pressure must be determined by a pressure test (see §180.413(d)(I 0)).  For the modification of the manway cover that you have described, this requirement may be met by the performance of a bench test of the modified cover, provided that your bench test fixture is representative of the manhole assembly on the cargo tank.  You need not complete a pressure test of the entire cargo tank.

I hope this information is helpful.  Please accept my apology for any confusion that may have resulted from our previous response.  If you have farther questions, please do not hesitate to contact this office.


Thomas G. Allan

Senior Transportation Regulations Specialist

Office of Hazardous Materials Standards


Regulation Sections

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