Interpretation Response #18-0024
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Versum Materials
Individual Name: Richard Schuyler
Location State: PA Country: US
View the Interpretation Document
Response text:
September 18, 2018
Richard Schuyler
Sr. Principal Mechanical Engineer
Versum Materials
357 Marian Avenue
Tamaqua, PA 18252
Reference No. 18-0024
Dear Mr. Schuyler:
This letter is in response to your February 21, 2018, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to pressure relief devices (PRDs) for Multi-Element Gas Cylinders (MEGCs). Specifically, you seek confirmation of your understanding that MEGCs transporting “UN2451, Nitrogen trifluoride” do not require PRDs in accordance with the Compressed Gas Association (CGA) S-1.1 pamphlet, which is incorporated by reference in § 171.7 of the HMR.
Your understanding is correct. In accordance with § 173.301(f), a cylinder filled with a gas and offered for transportation must be equipped with one or more PRDs sized and selected as to type, location, quantity, and tested in accordance with CGA S-1.1. When a person refers to CGA S-1.1, Table 3, the “T” code for nitrogen trifluoride indicates only specific PRDs are authorized for optional use during transportation thus, the CG-4 or CG-5 device must be used when a PRD is permissively selected. Please note, when an optional PRD is selected, a person must comply with the requirements in §§ 173.301(f) and 178.75(f) for MEGCs installed with a PRD when applicable.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division
171.7, 173.301(f), 178.75(f)