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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #17-0137

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

Interpretation Response Details

Response Publish Date:

Company Name: Precision Fabricators Ltd.

Individual Name: David Diamond

Location State: MA Country: US

View the Interpretation Document

Response text:

David Diamond
Precision Fabricators Ltd.
Stoughton, MA 02072

Reference No. 17-0137

Dear Mr. Diamond:

This letter is in response to your November 30, 2017, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to cylinders. Specifically, you ask whether a U.S. Department of Transportation (DOT) specification 4B cylinder may be used to transport 500 cubic centimeters (0.5 liter) of anhydrous ammonia mixture, of which half the cylinder will have anhydrous ammonia (liquid form) while the other half will have ammonia gas (vapor form).

DOT 4B cylinders are not authorized for anhydrous ammonia. The Column 8B entry for "UN1005, Anhydrous, ammonia" under the Hazardous Materials Table (HMT; § 172.101) requires this material to be placed in a non-bulk cylinder prescribed in § 173.304. DOT 4B cylinders are not included in the list of DOT cylinders authorized for use with anhydrous ammonia in § 173.304a(a)(2). Furthermore, the Column 8A entry under the HMT specifies there are no packaging exceptions for UN1005.

I hope this information is helpful. Please contact us if we can be of further assistance.


T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
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