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Interpretation Response #12-0236 ([Dynetek Industries Ltd.] [Mr. Stefan Frey])

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

Interpretation Response Details

Response Publish Date:

Company Name: Dynetek Industries Ltd.

Individual Name: Mr. Stefan Frey

Country: CA

View the Interpretation Document

Response text:

December 18, 2012

Mr. Stefan Frey
Head of Service and Systems Management
Dynetek Industries Ltd.
4410 46 Avenue SE
Calgary, AB T2B 3N7
Ref. No.: 12-0236

Dear Mr. Frey:

This is in response to your October 23, 2012 email requesting clarification of the requirements for filling DOT specification cylinders under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically you asked if a cylinder may be filled in excess of the marked service pressure.

A cylinder may be filled to a pressure in excess of the marked service pressure (1) in accordance with § 173.302a(b); or (2) to compensate for certain factors, such as heat of compression, high ambient temperature, or changes in elevation, provided the pressure in the cylinder at 21°C (70 °F) does not exceed the marked service pressure.  Except as otherwise provided in § 173.301a(d), the pressure in a cylinder may not exceed 5/4 times the service pressure at 55 °C (131 °F).

I hope this information is helpful.  If you have further questions, please do not hesitate to contact this office.


Delmer Billings
Senior Regulatory Advisor
Standards and Rulemaking Division


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
173.302 Filling of cylinders with nonliquefied (permanent) compressed gases or adsorbed gases