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Interpretation Response #10-0190 ([PCS Sales USA, Inc.] [Mr. Tracey G. Smith])

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

Interpretation Response Details

Response Publish Date:

Company Name: PCS Sales USA, Inc.

Individual Name: Mr. Tracey G. Smith

Location State: IL Country: US

View the Interpretation Document

Response text:

November 18, 2010



Mr. Tracey G. Smith

Manager, Regulatory Compliance

PCS Sales USA, Inc.

1101 Skokie Blvd.

Suite 400

Northbrook, IL 60062

Ref. No. 10-0190

Dear Mr. Smith:

This responds to your July 28, 2010 request for clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). According to your request, you have a gas transport trailer with constant volume and an occasional liquid residue that can only be loaded with a specific quantity of gas as provided by § 173.301a(d)(3). You ask two questions. First, you request clarification of the loading temperature used to calculate loading conditions under § 173.301a(d)(3). Second, you ask if you may disregard the liquid residue weight when filling 3AAX cylinders with a material that falls under § 173.301a(d)(3).

Section 173.301a(d)(3) clearly indicates that the pressure (developed pressure) may not exceed the service pressure of the cylinder at 55º C (131º F). The person responsible for filling the cylinder with liquefied compressed gas must consider both the temperature of the material at 55º C (131º F) and any residue remaining in the cylinder when calculating the filling density of material placed in the cylinder. This calculation ensures that sufficient outage is provided so the cylinder will not be liquid full at 55º C (131º F).

I hope this answers your inquiry. If you need additional assistance, please do not hesitate to contact this Office at 202-366-8553.


Ben Supko

Acting Chief, Standards Development

Office of Hazardous Materials Standards


Regulation Sections

Section Subject
173.301 General requirements for shipment of compressed gases and other hazardous materials in cylinders, UN pressure receptacles and spherical pressure vessels