W. R. Grace & Co. — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration April 16, 2024 1200 New Jersey Avenue, SE Washington, DC 20590 Mr. Paul Errichetti Sr. Mgr., Fleet and Dangerous Goods W. R. Grace & Co. 7500 Grace Drive Columbia, MD 21044 Reference No. 23-0065 Dear Mr. Errichetti: This letter is in response to your July 7, 2023, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to pressure relief devices on specification Department of Transportation (DOT) 51 portable tanks. In your letter, you state that you have a fleet of DOT 51 portable tanks—comprised of both 250 gallon and 430 gallon capacities—with a test pressure of 300 psig and a maximum allowable working pressure (MAWP) of 200 psig. Specifically, you ask whether the required pressure relief devices may start to discharge at less than 110% of two-thirds of the test pressure. The answer is no. As provided by § 178.275(g)(6)(ii)—and described in a previous Letter of Interpretation (LOI) Ref. No. 21-0035—the required pressure relief devices must be set to start to discharge at a nominal pressure of five-sixths of the test pressure for shells having a test pressure of not more than 4.5 bar (450 kPa) and 110% of two-thirds of the test pressure for shells having a test pressure of more than 4.5 bar (450 kPa). Since the applicable portable tanks have a test pressure of more than 4.5 bar (450 kPa), the start to discharge pressure for the pressure relief devices is required to be set at 110% of two-thirds of the test pressure (220 psig). I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, Steven W. Andrews Jr. Acting Chief, Regulatory Review and Reinvention Branch Standards and Rulemaking Division#

Page 2Pollack 23-0065 From: INFOCNTR (PHMSA) To: Dodd, Alice (PHMSA) Cc: Hazmat Interps Subject: FW: LOI for 49 CFR 178.275(g)(6)(ii) Date: Friday, July 14, 2023 10:56:17 AM Attachments: DOT-PHSMA LoI 49CFR178.275(g)(6)(ii) - 07Jul2023.pdf Hi Alice, Please see the attached interpretation request. Let us know if you need anything. Regards, -Breanna From: Errichetti, Paul <Paul.Errichetti@grace.com> Sent: Friday, July 7, 2023 11:11 AM To: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov> Subject: LOI for 49 CFR 178.275(g)(6)(ii) CAUTION: This email originated from outside of the Department of Transportation (DOT). Do not click on links or open attachments unless you recognize the sender and know the content is safe. Hi, Please find attached a request for a formal letter of interpretation. If you have questions with regards to this request please contact me via email or my mobile number listed below in my signature. Thanks, Paul Errichetti | Senior Manager, Fleet & Dangerous Goods W. R. Grace & Co – Conn. | 7500 Grace Drive, Columbia, MD 21044, USA | T +1 410.531.8215 | M +1 732.306.0683 | paul.errichetti@grace.com THIS EMAIL AND ANY ATTACHED FILES ARE CONFIDENTIAL AND MAY BE LEGALLY PRIVILEGED. If you are not the addressee, any disclosure, reproduction, copying, distribution, or use of this communication is strictly prohibited. If you have received this transmission in error please notify the sender immediately and then delete this email. Our privacy policy can be found here. At any time, you may change your preferences or remove your data by clicking here. Unsubscribe#

Page 3Paul Errichetti Sr. Mgr., Fleet and Dangerous Goods T +1 410.531.8215 M +1 732.306.0683 Paul.Errichetti@grace.com W. R. Grace & Co.-Conn. 7500 Grace Drive Columbia, MD, USA, 21044 July 7, 2023 Mr. Shane Kelley Director, Standards and Rulemaking Division U.S. DOT/PHMSA (PHH-10) 1200 New Jersey Avenue SE East Building, 2nd Floor Washington, DC 20590 Dear Mr. Kelley: I am contacting the agency on behalf of WR Grace with this formal request for a letter of interpretation regarding the Hazardous Materials Regulations 49 CFR 178.275(g)(6)(ii). We have a fleet of 250 gallon and 430 gallon DOT 51 portable tanks. The tanks have a test pressure of 300 psig and a maximum allowable working pressure of 200 psig. Based on the referenced above code, the pressure relief device on these tanks should start to discharge at 220 psig. Question: Can we set the pressure relief device on these tanks to start to discharge at 200 psig versus 110% of two-thirds of the test pressure which noted above would be 220 psig? If you have any questions or need clarification to my questions, please feel free to contact me by cell phone at (732) 306-0683 or via email at Paul.Errichetti@grace.com. Sincerely, Paul Errichetti Paul Errichetti Sr. Mgr., Fleet and Dangerous Goods 1 grace.com#