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Interpretation Response #11-0181

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

Interpretation Response Details

Response Publish Date: 11-16-2011
Company Name: McAda Fluids Heating Services    Individual Name: Mr. James S. McAda
Location state: TX    Country: US

View the Interpretation Document

Response text:

November 16, 2011



Mr. James S. McAda
McAda Fluids Heating Services
P.O. Box 1080
Bay City, Texas 77404

Ref. No. 11-0181

Dear Mr. McAda:

This responds to your letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to trailer-mounted oilfield water heating units with burners fueled by propane gas. The gas is transported in MC 331 specification tanks constructed in accordance with the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) and are mounted to the same trailer as the heating units. You ask whether the water heating units you describe in your letter are subject to the HMR and, if not, what actions you can voluntarily take to communicate the hazards posed by transporting such units on a public highway.

It is the opinion of this Office the tanks you describe are fuel tanks and, therefore, are not subject to the HMR. As defined in 49 CFR 171.8, a fuel tank means "a tank, other than a cargo tank, used to transport flammable or combustible liquid, or compressed gas for the purpose of supplying fuel for propulsion of the transport vehicle to which it is attached, or for the operation of other equipment on the transport vehicle." Fuel systems that meet the requirements under 49 CFR 393.65 and 393.67 of the Federal Motor Carrier Safety Regulations (FMCSR) and are not used as packaging for hazardous materials are subject only to the FMCSR. As prescribed in 49 CFR 393.69(a), a fuel system that uses liquefied petroleum gas as a fuel for the operation of a motor vehicle or for the operation of auxiliary equipment installed on, or used in connection with, a motor vehicle must conform to the "Standards for the Storage and Handling of Liquefied Petroleum Gases" of the National Fire Protection Association (NFPA), Battery March Park, Quincy, MA 02269.

Regarding voluntary hazard communication, it is permissible to display the FLAMMABLE GAS placard prescribed in 49 CFR 172.532. The HMR authorize placards to be displayed for a hazardous material, even when not required, provided the placarding conforms to the requirements in Subpart F of Part 172. See 49 CFR 172.502(c).

I trust 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

172.532, 172.502

Regulation Sections

Section Subject
§ 172.532 FLAMMABLE GAS placard