Interpretation Response #19-0025R

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

Interpretation Response Details

Response Publish Date: 12/22/2025

Company Name: Westmor Industries, LLC

Individual Name: Robbie Dunn, P.E.

Location State: MN Country: US

View the Interpretation Document

Response text:

December 22, 2025

Robbie Dunn, P.E.
Westmor Industries, LLC
3 Development Drive
Morris, MN  56267

Reference No. 19-0025R

Dear Mr. Dunn:

This letter is in response to your March 4, 2019 email and a meeting on May 19, 2025, with members of the Standards and Rulemaking Division, requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the transportation of propane in a specification MC 331 cargo tank motor vehicle (bobtail). After further review, Reference No. 19-0025 has been superseded by this revised letter.

You describe a scenario where propane deliveries require drivers to reverse into unfamiliar locations to complete the delivery of propane to customers. This presents safety concerns due to limited visibility and blind spots. As such, you are considering mounting a reel to the front of the bobtail chassis. Furthermore, you state that due to variations in chassis design or lack of structural support at the front of the bobtail chassis, you want to avoid installing a protection device. Based on the design drawing that was submitted, is the proposed configuration allowed by the HMR?

No. While there is not a restriction against mounting the hose reel and piping to the front of the MC 331 chassis, § 178.337-10(a) requires "[a]ll valves, fittings, pressure relief devices, and other accessories to the tank proper shall be protected in accordance with paragraph (b) of this section against such damage as could be caused by collision with other vehicles or objects..." Furthermore, in accordance with § 178.337-10(f)(2), each internal self-closing stop valve, excess flow valve, and check valve must be shielded by a shear section or other sacrificial device.

This protection device must be placed in the piping system outboard of the stop valve and within the accident damage protection device to prevent any accidental loss of lading. Based on the information and attachments provided, your design would not meet the accident damage protection requirements prescribed in § 178.337-10.

I hope this information is helpful. Please contact us if we can be of further assistance.

Sincerely,

Dirk DerKinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

§ 178.337-10, § 178.337-10(a), § 178.337-10(f)(2)

Regulation Sections