Bancroft Hinchey Ltd. — Hazardous Materials Safety Interpretation

Page 11200 New Jersey Avenue, SE Washington, DC 20590 U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration June 24, 2025 Kevin Turner Training & Assurance Manager Bancroft Hinchey Ltd. Unit 7A, Hartley Business Park Selborne Road Alton, Hampshire, GU343HD Reference No. 25-0004 Dear Mr. Turner: This letter is in response to your January 10, 2025 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to pressure tests and system checks performed on cylinders. You state that the pressure test requirement in § 180.205(g) of the HMR permitting a “system check” to be performed at a pressure up to 90% of test pressure conflicts with instruction offered in the Compressed Gas Association (CGA) publication, C-1, “Methods for Pressure Testing Compressed Gas Cylinders,” which is incorporated by reference in § 180.205(g). Specifically, CGA C-1 provides instruction for a cylinder to be pressurized to less than 90% of the minimum test pressure. You provide an example of a DOT 3AA cylinder with a service pressure of 1800 psi, which is pressurized during a system check to 2700 psi1 (i.e., exactly 90% of the minimum required test pressure). Specifically, you ask, would pressurizing the cylinder to 90% of the test pressure rather than below be considered a “system check” instead of a test? Yes. Based on the example you provided, it is the opinion of this Office that what you describe would be considered a system check. While § 180.205 requires pressure testing in accordance with CGA C-1, § 180.205(g) allows a system check to be performed at or below 90% of test pressure. Section 180.205(g) does not require adhering to CGA C-1 which prescribes a system check below 90% of test pressure. However, because any pressurization that exceeds 90% would be considered a test, performing a system check at 1 Table 1 to paragraph (a) of § 180.209 – DOT 3AA cylinders must have a minimum test pressure of 5/3 times service pressure, except non-corrosive service (see § 180.209(g)). As such, 1800 psi x 5/3 = 3000 psi.#

Page 2pressures below 90% is more conservative as it ensures that a cylinder is not inadvertently pressurized over 90% of test pressure (e.g., due to minor gauge tolerance differences). 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#

Page 3Casey 25-0004 From: INFOCNTR (PHMSA) To: Dodd, Alice (PHMSA) Cc: Hazmat Interps Subject: FW: 49CFR - Interpretation request - Hydrostatic Testing - Maximum System Check Pressure Date: Friday, January 10, 2025 4:54:07 PM Attachments: image001.png Hello Alice, See the attached interpretation request. Let us know if you need anything else. Best, Aminah From: Kevin Turner - Bancroft <kevin.turner@bancroft.co.uk> Sent: Friday, January 10, 2025 9:25 AM To: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov> Subject: 49CFR - Interpretation request - Hydrostatic Testing - Maximum System Check Pressure You don't often get email from kevin.turner@bancroft.co.uk. Learn why this is important 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. Good afternoon Please can we have a clarification on a conflict between the information presented in §180.205(g)(5): “A system check may be performed at or below 90% of test pressure prior to the retest…..” And the information presented in CGA C-1 2016 (5.7 – Cylinder retesting): “When conducting water jacket testing it is highly recommended that the cylinder be pressurized in the water jacket to a pressure less than 90% of its test pressure before conducting a volumetric expansion test…….If a cylinder is pressurised below 90% of minimum test pressure….. this does not count as a test….” The apparent conflict is “at or below”, vs “below” So as an example, does pressurising a DOT-3AA 1800 cylinder to exactly 2700 psi count as a system check, or a test? Many thanks#

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