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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 #11-0278 ([Thunderbird Cylinder] [Mr. Fred Nachman])

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

Interpretation Response Details

Response Publish Date:

Company Name: Thunderbird Cylinder

Individual Name: Mr. Fred Nachman

Location State: AZ Country: US

View the Interpretation Document

Response text:

April 2, 2012


Mr. Fred Nachman
Thunderbird Cylinder
4209 E. University Drive
Phoenix, AZ 85034-7315

Reference No.: 11-0278

Dear Mr. Nachman:

This responds to your letter requesting clarification of Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the requalification and condemnation requirements for compressed gas cylinders. Specifically, you ask for clarification and direction from the Department of Transportation (DOT) regarding foreign manufactured aluminum medical home oxygen cylinders, some of which have shown an identifiable release of hazardous materials to the environment during their usage.

In your incoming letter, you describe a scenario in which your company (Thunderbird) was advised by the sales representative of a foreign manufacturer of medical home oxygen cylinders that there were numerous incidents of leakage upon the initial shipments of this foreign manufacturer"s cylinders five-six years ago, due to defects in both the cylinders and the valves. During your most recent requalification operations, Thunderbird requalified and reinstalled the existing valves back into the above referenced cylinders, of which many were, subsequently, returned by users as defective and leaking. During an investigation by Thunderbird and DOT officials, it was verified that the leaking of the cylinders was caused by one or more of the following reasons: 1) rough and shallow cutting of neck threads by the manufacturer, 2) initial over-torqueing of valves after manufacture, 3) burrs, 4) thread damage from handling, 5) oversized diameter and depth of the counter bore, and 6) possible non-specification aluminum used for construction. You seek guidance regarding the disposition of these cylinders.

Section 180.205 provides the general requirements for requalification of specification cylinders, including the requirements for cylinder condemnation. In accordance with § 180.205(i)(1)(i), a cylinder must be condemned when the cylinder meets a condition for condemnation under the visual inspection requirements of § 180.205(f). As specified in
§ 180.205(f)(3) each cylinder subject to a visual inspection must be approved, rejected or condemned according to the criteria in the applicable Compressed Gas Association (CGA) pamphlet, in this case CGA-6.1, 2002 edition. CGA-6.1 specifies in 5.9, that a cylinder must be rejected when the neck threads are materially reduced so that a gas tight seal cannot be obtained by reasonable valving methods. Therefore, the cylinders you describe in your incoming letter must be rejected as they are not in compliance with the applicable CGA pamphlet as required by § 180.205(f)(3). Furthermore, it should be noted that § 171.2(e) forbids offering for transportation a damaged packaging containing a hazardous material.

I hope this satisfies your inquiry. 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
180.205 General requirements for requalification of specification cylinders