Interpretation Response #08-0157 ([HMT Associates, L.L.C.] [Mr. E.A. Altemos])

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

Interpretation Response Details

Response Publish Date: 07/23/2008

Company Name: HMT Associates, L.L.C.

Individual Name: Mr. E.A. Altemos

Location State: VA Country: US

View the Interpretation Document

Response text:

July 23, 2008

Mr. E.A. Altemos

HMT Associates, L.L.C.

603 King Street

Alexandria, VA 22314-3105

Ref. No.: 08-0157

Dear Mr. Altemos:

This responds to your letter dated May 9, 2008, requesting clarification on the Pipeline

and Hazardous Materials Safety Administration's (PHMSA) March 5, 2008 response to Mr. Dave Bailey [Letter Reference No. 07-0147 enclosed] regarding the performance requirements for shear sections on IM101 portable tanks. Specifically, you request clarification of Q3 and A3 of that letter. The letter from Mr. Dave Bailey referenced both IM101 and UN portable tanks, yet the answer to Q3 does not differentiate the two. You correctly assert that the performance requirements for IM101 and UN portable tanks are different, and request that Q3 be revised to reflect those differences. The answer to Q3 of the May 9, 2008 letter is revised to read as follows:

Q3. In a Safety Advisory Notice (62 FR 37638), PHMSA clarified that internal discharge valves and shear sections are safety devices required on the bottom-outlets of IM portable tanks in hazardous material service to prevent significant release of lading when damage is sustained at the filling/discharge connection. Does the performance standard allow for some leakage of the tanks lading?

A3(a). For UN portable tanks, the shear section or sacrificial device must break at no more than 70% of the load that would cause failure of the internal self closing stop valve. Provided the shear section satisfies this performance requirement, some leakage may occur.

A3(b). For IM101 portable tanks, the performance requirement applicable to shear sections was previously specified in § 178.270-12(d) [Removed: 72 FR 55678 (HM-244); October 1, 2007] of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). The requirement specifies that the shear section must break under strain



without affecting the product retention capabilities of the tank and any attachments. Therefore, there may be no leakage of lading from an IM101 portable tank related to the performance of the shear section.

I hope this information is helpful. Please contact us if you require additional assistance.

Sincerely,

Edward T. Mazzullo

Director, Office of Hazardous

Materials Standards

178.270-12,178.274

Regulation Sections