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The United States Pipeline and Hazardous Materials Safety Administration (“PHMSA”) addressed in a September 20th interpretive letter a request for clarification of the Hazardous Materials Regulations (“HMR”) applicable to cryogenic liquids.
The letter was in response to a May 24th request from Cryogenic Services, Ltd. (“CSL”).
CSL informed PHMSA in its May 24th letter that it transports multiple 180 L cyclinders at 22 psig by highway. The company asks for clarification regarding the use of the exceptions for cryogenic liquids as provided in § 173.320.
CSL first asks whether there is a size limitation on packagings that qualify for the exceptions provided in § 173.320.
PHMSA answers in the negative. It states:
The exception for cryogenic liquids does not limit the size of the packaging; however, it does limit the type of packaging to Dewar flasks, insulated cylinders, insulated portable tanks, insulated cargo tanks, and insulated tank cars that are designed and constructed so that the pressure will not exceed 25.3 psig under ambient conditions.
Second, the company asks whether in using the cryogenic liquids exceptions it is required to placard the motor fuel when transporting a Dewar flask or cylinder at 22 psig or less.
PHMSA again answers in the negative except for an instance in which refrigerated liquid oxygen is being transported.
Third, the company asks whether it is subject to the registration requirements in § 107.601.
PHMSA responds that if subject to placarding (e.g., liquid oxygen in non-bulk cylinders exceeding 1000 pounds gross weight), then the answer is stated to be yes. Section 107.601(a)(6) is cited. The agency further states that otherwise the answer is no.
Finally, it is asked whether § 173.320 specifies how these packages should be secured inside the vehicle.
PHMSA answers in the negative, noting:
While § 173.320 provides relief from the specific loading and unloading requirements prescribed in§ 177.834, you are still required to comply with the Federal Motor Carrier Safety Administration's regulations (FMCSR), which have requirements that address protection against shifting or falling cargo (see FMCSR; 49 CFR Part 393 Subpart I - Protection Against Shifting and Falling Cargo).
A copy of the letter can be downloaded here.
