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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 #13-0110 ([Kidde-Fenwal, Inc.] [Mr. Richard Lupien])

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

Interpretation Response Details

Response Publish Date:

Company Name: Kidde-Fenwal, Inc.

Individual Name: Mr. Richard Lupien

Location State: MA Country: US

View the Interpretation Document

Response text:

August 29, 2013



Mr. Richard Lupien
Manager, Combustion Research Center
Kidde-Fenwal, Inc.
90 Brook Street
Holliston, MA 07146

Ref. No.: 13-0110

Dear Mr. Lupien:

This is in response to your May 16, 2013 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to pressure relief devices (PRD) on Department of Transportation 4BW-250 specification cylinders.  In your letter, you state that you manufacture a fixed fire suppression system that utilizes DOT- 4BW250 cylinders filled with a dry chemical agent and pressurized with nitrogen to a pressure of 175 psig at 70 °F.  Specifically, you ask if you may use a UL-rated fusible plug instead of a CG-3 fusible plug required by Compressed Gas Association (CGA) publication S-1.1.  

Unless excepted, a cylinder filled with a gas and offered for transportation must be equipped with one or more pressure relief devices sized and selected as to type, location, and quantity, and tested in accordance with CGA S-1.1 (see § 173.301(f)(1)).  Section 173.301(f)(5)(ii) states that a pressure relief device is not required on “a cylinder with a water capacity of less than 454 kg (1000 lbs) filled with a nonliquefied gas to a pressure of 300 psig or less at 21 °C (70 °F), except for a DOT 39 cylinder or a cylinder used for acetylene in solution.”  The cylinders provided in your example do not require pressure relief devices.  However, should you choose to install a PRD, it must conform to CGA publication S-1.1.

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