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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 #12-0037 ([Naval Ordnance Safety and Security Activity] [Mrs. Karen Bonnin])

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

Interpretation Response Details

Response Publish Date:

Company Name: Naval Ordnance Safety and Security Activity

Individual Name: Mrs. Karen Bonnin

Location State: MD Country: US

View the Interpretation Document

Response text:

April 2, 2012


Commanding Officer
Naval Ordnance Safety and Security Activity
Attn: Mrs. Karen Bonnin
Farragut Hall
3817 Strauss Avenue, Suite 108
Indian Head, MD 20640-5151

Ref. No. 12-0037

Dear Mrs. Bonnin:

This responds to your request for written clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the classification of certain pressure vessels that are integral components of Sidewinder Guidance Units (GU) and Captive Air Training Missiles (CATM) as part of the Sidewinder Missile (AIM-9X) Program. The non-specification pressure vessels have a volumetric capacity of 95 cc (5.8 cubic inches) and are charged with helium at 450 psig. You ask whether the GU and CATM units may be alternatively described as "UN3363, Dangerous goods in apparatus, 9" in lieu of "UN1046, Helium, compressed, 2.2."

The answer is yes. As prescribed in § 173.222(b)(3), a receptacle for gas, its contents and filling densities, must conform to the applicable requirements of the HMR. Because the pressure vessels meet the non-specification pressure vessel provisions under § 173.306(a)(1) of the HMR, they may be described as "UN3363, Dangerous goods in apparatus, 9." We intend to address this regulatory inconsistency you highlight in the § 172.102 Special provision 136 eligibility criteria in a future rulemaking. Additionally, this interpretation is consistent with the intent of the international standard on which this provision is based.

I trust this satisfies your inquiry. Please contact us if we can be of any further assistance.



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

A173.222, 172.102

Regulation Sections

Section Subject
173.222 Dangerous goods in equipment, machinery or apparatus