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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 #14-0030 ([Burdette & Associates, Inc.] [Mr. Michael Burdett])

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

Interpretation Response Details

Response Publish Date:

Company Name: Burdette & Associates, Inc.

Individual Name: Mr. Michael Burdett

Location State: LA Country: US

View the Interpretation Document

Response text:

July 31, 2014

Mr. Michael Burdett, P.E.
Burdette & Associates, Inc.
P.O. Box 264
Milton, LA 70558

Ref. No.: 14-0030

Dear Mr. Burdette:

This is in response to your letter dated February 17, 2014, requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) relating to the use of a DOT Specification 57 portable tank with a modified fill opening that exceeds 20 square inches. I apologize for the delay in response and hope that it has not caused any inconvenience.

You describe a scenario where the fill opening of a DOT 57 portable tank is modified with an 8-inch diameter Camlock coupling and cap. The 8-inch Camlock coupling has an opening of approximately 50 square inches. You ask if this modification conforms to the requirements of the HMR.

As you pointed out in your letter, the specification for a DOT 57 portable tank included §187.253-2(a)(1), which stated, "Any closure for a fill opening in excess of 20 square inches must be equipped with a device to prevent the closure from fully opening without first relieving internal pressure." In a final rule published under docket HM-181E (59 FR 38040; July 26, 1994), the manufacture of a DOT 57 portable tank was no longer authorized as of October 1, 1996. Therefore, § 178.253 was removed from the HMR. However, §173.32(c)(1) provides for the continued use of an existing portable tank conforming to DOT Specification 57 if it was constructed before October 1, 1996.

The described modifications to the portable tank (the fill opening enlarged to greater than 20 square inches and the installation of a Camlock coupling and cap) does not conform to DOT Specification 57 and the portable tank, so equipped is not authorized for continued use under §173.32(c)(1). A Camlock coupling and cap acts solely as a quick-disconnect device and does not prevent the closure from fully opening without first relieving the pressure within the tank. In order for the portable tank with a fill opening in excess of 20 square inches to be in compliance with DOT Specification 57, the Camlock coupling and cap or the tank itself must be equipped with a device that prevents the closure from fully opening without first relieving internal pressure. A pressure release device such as a petcock installed on the tank, or on the Camlock coupling or cap, would also not conform with DOT Specification 57 unless the installation also prevented the closure from fully opening prior to relieving the pressure within the tank. While the use of a petcock may effectively relieve the internal pressure from the tank it would not prevent the closure from fully opening while the tank is still pressurized. A safety hazard exists if a person fails to first relieve the pressure in the tank by opening the petcock and opens the Camlock cap while the tank is still pressurized.

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

Sincerely,

Shane C. Kelley
Acting International Standards Coordinator
Standards and Rulemaking Division

187.253-2(a)(1), 178.253, 173.32(c)(1)

Regulation Sections

Section Subject
173.32 Requirements for the use of portable tanks