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Interpretation Response #10-0143 ([URS Corporation] [Mr. Andrew Romach])

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

Interpretation Response Details

Response Publish Date:

Company Name: URS Corporation

Individual Name: Mr. Andrew Romach

Location State: NC Country: US

View the Interpretation Document

Response text:

September 17, 2010




Mr. Andrew Romach

Regulatory Compliance Manager

URS Corporation

1600 Perimeter Park Drive

Morrisville, NC 27560

Ref. No. 10-0143

Dear Mr. Romach:

This responds to your July 8, 2010 letter regarding the applicability of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) to the transportation of a fire extinguisher. According to your letter and subsequent telephone conversation with a member of my staff, portable structures such as mobile office trailers and freight containers configured as jobsite trailers are transported by contracted motor vehicle to various jobsites for use as temporary structures. These structures are often outfitted with a portable fire extinguisher mounted to an interior wall for use in emergency when the structures are occupied or in use. The fire extinguishers are primarily placed in the structures because of Occupational Safety and Health Administration (OSHA) requirements (e.g., see 29 CFR 1910.157 and 1910.252) or local fire codes but are also placed in the structures based on company policy. Specifically, you request clarification of the applicability of the HMR to the transportation by highway of a fire extinguisher incorporated as part of a portable structure.

You reference a June 12, 2007, letter of interpretation (Ref. no. 07-0092) in which PHMSA clarifies that a fire extinguisher that is an integral part of a motor vehicle is not in commerce and thus, is not subject to regulation under the HMR. It is your understanding that a portable structure such as a mobile office trailer functions as a motor vehicle and therefore, a fire extinguisher mounted on the interior of the trailer would be considered an integral part of the motor vehicle, and thus, not in commerce. Additionally, for those instances when a fire extinguisher is required safety equipment which must be mounted in a motor vehicle, trailer, or freight container; or mounted on equipment transported aboard a motor vehicle or trailer, you ask whether the fire extinguisher is always considered integral to the motor vehicle and therefore, not in commerce.

The portable structures you describe in your letter are jobsite trailers. They are not used for the purpose of transporting hazardous material as was the case in the June 2007 letter you reference.

It is the opinion of this Office that fire extinguishers transported in portable structures (i.e., jobsite trailers) for safety purposes and in accordance with OSHA requirements or local fire codes are not in commerce. Thus, the fire extinguishers are not subject to the HMR.

I hope this information is helpful. If you have further questions, please contact this office.


Ben Supko

Acting Chief, Standards Development

Office of Hazardous Materials Standards

173.159, 173.309

Regulation Sections

Section Subject
173.159 Batteries, wet
173.309 Fire extinguishers