Interpretation Response #24-0112
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: National Propane Gas Association
Individual Name: Benjamin A.F. Nussdorf
Location State: DC Country: US
View the Interpretation Document
Response text:
August 12, 2025
Benjamin A.F. Nussdorf
General Counsel/Vice President, Regulatory & Industry Affairs
National Propane Gas Association
1140 Connecticut Avenue, NW
Suite 1075
Washington, DC 20036
Reference No. 24-0112
Dear Mr. Nussdorf:
This letter is in response to your November 18, 2024 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to emergency discharge control equipment for liquefied compressed gas in cargo tank motor vehicles (CTMVs). Regarding metered service, it is your understanding that the phrase "shut off all motive and auxiliary power equipment" located in § 173.315(n)(3) of the HMR refers only to shutting down the equipment used for product transfer to prevent uncontrolled or accidental discharge of hazardous material and the vehicle engine. Specifically, you ask whether this language in § 173.315(n)(3) is meant to only shut off product transfer equipment and the vehicle's engine but not to shut off all electrical power on the vehicle.
Your understanding is correct. As provided by § 173.315(n)(3), the phrase "all motive and auxiliary power equipment" refers only to the vehicle’s engine and the equipment that is directly responsible for operating the vehicles product transfer system—not all electrical power to the vehicle. The intent of the regulation is to close the internal self-closing stop valve and shut off all motive and auxiliary power equipment upon activation to prevent uncontrolled or accidental discharge of hazardous materials and eliminate potential sources of ignition.
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
§ 173.315(n)(3)
Regulation Sections
| Section | Subject |
|---|---|
| 173.315 | Compressed gases in cargo tanks and portable tanks |