USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

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

Interpretation Response #16-0187 ([Swagelok Northern California] [Mr. Cameron Banks])

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

Interpretation Response Details

Response Publish Date:

Company Name: Swagelok Northern California

Individual Name: Mr. Cameron Banks

Location State: CA Country: US

View the Interpretation Document

Response text:

April 19, 2017

Mr. Cameron Banks
Account Manager
Swagelok Northern California
3393 West Warren Avenue
Fremont, CA 94538

Reference No. 16-0187

Dear Mr. Banks:

This letter is in response to your November 14, 2016, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to cylinder valve integrity. In your email, you cite the valve pressure capability requirements under § 173.40(c)(1) as an example of valve integrity for cylinders used in toxic-by-inhalation service. Specifically, you ask whether the valve of a Department of Transportation (DOT) Specification 4B cylinder must meet either the minimum service pressure or test pressure requirements of the HMR.

You are correct in your citation that for cylinders in toxic-by-inhalation service "each plug or valve capable of withstanding the test pressure of the cylinder without damage or leakage" as stated in § 173.40(c)(1). The HMR do not include a similar requirement (such as valve pressure ratings) for cylinders not in toxic-by-inhalation service; however, there are valve requirements provided in the general requirements for cylinders (see § 173.301). For DOT Specification 4B cylinders, § 178.50(h) specifies the thread requirements, including engaged threads and shear strength.

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
173.40 General packaging requirements for toxic materials packaged in cylinders