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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 #11-0238 ([NitroxFox LLC.] [Mr. John Fox])

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

Interpretation Response Details

Response Publish Date:

Company Name: NitroxFox LLC.

Individual Name: Mr. John Fox

Location State: FL Country: US

View the Interpretation Document

Response text:

November 17, 2011

 

 

Mr. John Fox

NitroxFox LLC.

P.O. Box 32091

Sarasota, Florida 34239

Reference No.: 11-0238

Dear Mr. Fox:

This responds to your September 16, 2011 letter regarding the cleaning requirements for compressed gas cylinders containing breathing enriched air (Nitrox) under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, this is a follow-up letter in response to your previous request for a letter of interpretation (Ref. No. 11-0175) and asks additional questions pertaining to the cleaning requirements for cylinders used for the containment of Nitrox with elevated levels of oxygen ranging from 21% to 100%. Your questions are paraphrased and answered as follows:

Q1: If an aluminum Department of Transportation (DOT) specification cylinder is to be used to transport Nitrox with elevated levels of oxygen ranging from 21% to 100%, must the cylinder cleaning conform to the cleanliness requirements specified in 173.302(b)?

A1: The answer is yes. As noted in the response to your previous request for a letter of interpretation (Ref. No. 11-0175), if the oxygen concentration is greater than 23.5%, the conditions specified in § 173.302(b) must be met. Each DOT aluminum cylinder in oxygen service must be cleaned in accordance with the requirements of General Services Administration (GSA) Federal Specification RR"C"901D, paragraphs 3.3.1 and 3.3.2 (Incorporated By Reference (IBR), see § 171.7). Cleaning agents equivalent to those specified in GSA Federal Specification RR"C"901D may be used, provided they do not react with oxygen. One cylinder, selected at random from a group of 200 or fewer and cleaned at the same time, must be tested for oil contamination in accordance with GSA Federal Specification RR"C"901D, paragraph 4.3.2, and meet the specified standard of cleanliness.

Q2. If an Aluminum United Nations (UN) pressure receptacle is to be used to transport Nitrox with elevated levels of oxygen ranging from 21% to 100%, must the cylinder cleaning conform to the cleanliness standards specified in § 173.302(b)?

A2: The answer is yes. If the oxygen concentration is greater than 23.5%, the conditions specified in § 173.302(b) must be met. Each Aluminum UN pressure receptacle in oxygen service, must be cleaned in accordance with the requirements of International Standards Organization (ISO) 11621 (IBR, see §171.7).

Q3: In your current incoming letter, you state it is your opinion that GSA Federal Specification RR"C"901D does not contain "detailed cleaning procedures." Based on this lack of "detailed cleaning procedures" you ask if a cleaning standard equivalent to those specified in § 173.302(b) may be used to clean aluminum DOT specification cylinders and UN pressure receptacles used to transport Nitrox with elevated levels of oxygen ranging from 21% to 100%?

A3: As provided in § 173.302(b), PHMSA requires that each DOT aluminum cylinder in oxygen service meet the "requirements" of GSA Federal Specification RR"C"901D, paragraphs 3.3.1 and 3.3.2, not a specific "detailed cleaning procedure." Although GSA Federal Specification RR"C"901D does not provide a specific procedure for the cleaning of aluminum DOT cylinders used in oxygen service, it does provide requirements for the cleaning of cylinders including, but not limited to, the amount of rust bloom permitted, oil and hydrocarbon guidance and cleanliness verification methods. Provided the requirements of GSA Federal Specification RR"C"901D, paragraphs 3.3.1 and 3.3.2 are met, the requirements of § 173.302(b) are satisfied.

For aluminum DOT specification cylinders in oxygen service, other standards such as ISO 11621, Compressed Gas Association (CGA) guidelines, and MIL STD 1330D are permitted to be used provided they are equal to or more stringent than the requirements specified in GSA Federal Specification RR"C"901D, the cleaning agents are equivalent to those specified in GSA Federal Specification RR"C"901D and the cleaning agents do not react with oxygen.

Aluminum UN pressure receptacles in oxygen service, must be cleaned in accordance with the requirements of ISO 11621 (IBR, see §171.7) and no other equivalent standard may be used.

Q4. If an aluminum cylinder, used to transport Nitrox with elevated levels of oxygen ranging from 21% to 100%, is marked with a DOT specification marking, must it be maintained to that specification, including the cleaning requirements specified in

§ 173.302(b), if applicable, when it is no longer in commerce?

A4. The answer is yes. Cylinders that are filled and used solely on a private work-site and not offered for transportation in commerce are subject to the Occupation Safety and Health Administration (OSHA) Standards. In accordance with OSHA standard 29 CFR § 1910.101, each employer shall determine that compressed gas cylinders under their control are in a safe condition to the extent that this can be determined by visual inspection conducted as prescribed in the HMR. As stated in 49 CFR

§ 180.205(b), no person may mark a cylinder to represent that it meets a DOT specification unless all applicable requirements of 49 CFR subpart C of Part 180 have been met, a cylinder that is marked to certify that it conforms to HMR requirements, including the requirements specified in § 173.302 if applicable, must be maintained in accordance with applicable specification requirements in the HMR whether or not it is in transportation in commerce. If the owner of the DOT specification cylinder wishes to continue to use the cylinder but does not wish to re-qualify the cylinder as a specification cylinder, the owner must obliterate or cover any specification markings whether or not it is being used to transport hazardous materials in commerce.



I hope this satisfies your inquiry.

Sincerely,

T. Glenn Foster

Chief, Regulatory Review and Reinvention Branch

Standards and Rulemaking Division

173.302, 180.205

Regulation Sections

Section Subject
171.7 Reference material
173.302 Filling of cylinders with nonliquefied (permanent) compressed gases or adsorbed gases
180.205 General requirements for requalification of specification cylinders