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The Pipeline and Hazardous Materials Safety Administration (“PHMSA”) clarified in an August 12th Interpretive Letter the Hazardous Materials Regulations (“HMR”) applicable to emergency discharge control equipment for liquefied compressed gas in cargo tank motor vehicles (“CTMVs”).
PHMSA was responding to a November 18th letter from the National Propane Gas Association (“NPGA”).
The Interpretive Letter provided in part:
…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.
NPGA had asked whether this language in the cited section of the HMR 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.
PHMSA responds in the affirmative.
The agency notes that 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.
PHMSA states that 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.
A copy of the August 12th PHMSA Interpretive Letter and the NPGA November 18, 2024, inquiry can be downloaded here.
