Versum Materials — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 SEP 1 6 20 \8 Richard Schuyler Sr. Principal Mechanical Engineer V ersum 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 l 78.75(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, irk r Kin en Chief, Stand rds Development Branch Standards and Rulemaking Division#

Page 2. v VERSUM MATERIALS -~tQ__,t_ § i7~. '7~/({) t 7 oJ 30 ! (p) 1 1 -;) j , fl VERSUM MATERIALS, US LLC IOuo(u, bet- 357 Marian Ave. 0 Tamaqua, PA 18252 I . v ~ 1 ," n L I t . 510-461-0001 t L{) rx T VersumMaterials.com February 21, 2018 E-Mail infocntr@dot.gov ATTN : Hazardous Materials Information Center SUBJECT: Letter of Interpretation REF: 49 CFR § 178.75(f)(1) and 173.301(f) To Whom It May Concern: In accordance with 49 CFR § 105.20(2), I am writing to you seeking guidance regarding the above referenced citation from Title 49 of the Code of Federal Regulations. Versum Materials is currently expanding our fleet of Multi-Element Gas Containers (MEGCs) used for domestic and international transport of Nitrogen Trifluoride (NF3). During 3rd party design approval and MEGC certification process, the design basis for pressure relief devices (PRDs) has been questioned. For the reasons explained in the following paragraphs, we believe that PRDs are not required to be installed on NF3 MEGCs. Per§ 178.75 Specifications for MEGCs (f) Pressure relief devices. Each pressure receptacle must be equipped with one or more pressure relief devices as specified in§ 173.301(!) of this subchapter. When pressure relief devices are installed, each pressure receptacle or group of pressure receptacles of a MEGC that can be isolated must be equipped with one or more pressure relief devices. Pressure relief devices must be of a type that will resist dynamic forces including liquid surge and must be designed to prevent the entry of foreign matter, the leakage of gas and the development of any dangerous excess pressure. (1) The size of the pressure relief devices: CGA 5-1.1 {/BR, see §171.7 of this subchapter) must be used to determine the relief capacity of individual pressure receptacles. Per§ 173.301 General requirements for shipment of compressed gases and other hazardous materials in cylinders, UN pressure receptacles and spherical pressure vessels. (f) Pressure relief device systems. VERSUMMATERIALS.COM Versum Materials Confidential#

Page 3(1) Except as provided in paragraphs (f)(5} through (f)(7) and U) of this section, and §171.23(0) of this subchapter, 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 5-1.1 (compliance with paragraph 9.1.1.l is not required) and CGA Pamphlet 5-7 {!BR, see §171.7 of this subchapter). The pressure relief device must be capable of preventing rupture of the normally filled cylinder when subjected to a fire test conducted in accordance with CGA C-14 {!BR, see §171.7 of this subchapter}, or, in the case of an acetylene cylinder, CGA C-12 {/BR, see §171.7 of this subchapter). CGA S-1.1 is cited as the basis for selection and sizing of PRDs. The 12th edition of CGA S-1.1 is incorporated by reference in the Hazardous Material Regulations per 49 CFR §171.7. In accordance with Table 3 of CGA S-1.1 (12th ed.), the following device assignment is listed for Nitrogen Trifluoride: No PRD required. This device (i.e., CG-4 or CG-5) is to be selected if a PRD is used. We have determined that no PRDs are required to be installed on NF3 MEGCs, per the above basis. We herein request a letter of interpretation to validate this design basis as required to support 3rd party approval and certification. Thank you in advance for your attention to this matter. Please do not hesitate to contact me if you have any questions or need any additional information. Richard R. Schuyler, P .E. Sr. Principal Mechanical Engineer Versum Materials 2 Versum Materials Confidential#