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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 #18-0042

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

Interpretation Response Details

Response Publish Date:

Company Name: Defense Logistics Agency Aviation

Individual Name: David R. Carns

Location State: VA Country: US

View the Interpretation Document

Response text:

February 25, 2019

Mr. David R. Carns
Director, Aviation Engineering
Defense Logistics Agency Aviation
8000 Jefferson Davis Highway
Richmond, VA  23297-5002

Reference No. 18-0042

Dear Mr. Carns:

This letter is in response to your February 15, 2018, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the use of U.S. Department of Transportation Special Permit (DOT-SP) 10945.  You explain that DLA Aviation, a Major Subordinate Command of the Defense Logistics Agency (DLA), the U.S. Department of Defense’s (DOD) Combat Logistics Support Agency, procures a pneumatic accumulator subject to DOT-SP 10945.  The pneumatic accumulator is a non DOT specification fully wrapped carbon fiber reinforced aluminum lined cylinder authorized for the transportation of certain Division 2.1 and 2.2 gases in commerce .  The cylinders are shipped in an empty state to the point of installation on DOD aircraft, and at no time will they be offered for transportation or transported in a filled condition. 

We have paraphrased and answered your questions as follows:

Q1.   You ask if the cylinders described in your scenario  are subject to the requalification and service life limitations prescribed in DOT-SP 10945.

A1.   The answer is yes.  As prescribed in § 171.2(g), no person may represent, mark, or offer a packaging as meeting the requirements of a special permit unless the packaging is maintained, marked, and retested in accordance with the applicable requirements of the special permit.  Because the cylinders are represented as meeting the requirements of DOT-SP 10945, they must be maintained in accordance with the special permit as limited by the HMR.

Q2.   You ask if a cylinder is subject to the requalification tests as prescribed in DOT-SP 10945 regardless of whether the cylinder has been placed in service for its end-use application.

A2.  The answer is yes.  Cylinders retested after July 1, 2001, must be reinspected and hydrostatically retested at least once every 5 years from the date of the original manufacturing tests and 5 years thereafter regardless of whether the cylinder was in service or otherwise. 

Q3. You ask if the 5-year retest “clock” begins on the cylinder date of manufacture (i.e., original test date) or installation in its end-use platform (i.e., aircraft).

A3. The 5-year retest requirement is based on the original test date.

Q4. Paragraph 7.d.(1) of the special permit states that cylinders manufactured under DOT-SP 10945 are not authorized for use 15 years after the date of manufacture.  For a cylinder that is unused (e.g., in storage) or is in an empty state for an extended period, you ask if it is permissible to account for the time in such a way that it extends the service life of the cylinder beyond the 15 years as prescribed in the special permit.

A4. The answer is no.  Under DOT-SP 10945, the service life is limited to 15 years from the date of the original testing performed in the manufacturing process and is marked on the cylinder.
I hope this information is helpful.  Please contact us if we can be of further assistance.


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




Regulation Sections

Section Subject
171.2 General requirements