Koorsen Fire & Security — Hazardous Materials Safety Interpretation

Page 1Baker, Y. 26-0052 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 Brick Keltner Corporate Shop Trainer Koorsen Fire & Security 2820 N. Webster Indianapolis, In 46219 Telephone 317-225-4785 Email: brick.keltner@koorsen.com Mr. Kelley, I would like a Formal Interpretation of 49 CFR 180.215(b)(1). Reporting & record retention for Calibration test records. The question that I have relates to the Calibrated Cylinder serial number. In the above standard it states that the serial number of the Calibrated Cylinder must be on the calibration / test records. Is that for Water Jacket testing as well as Proof Pressure testing? I have always taken the standards to mean for both methods unless it is otherwise stated. 49 CFR references CGA C-1 in multiple instances. CGA C-1 - 5.4 states – A calibrated cylinder is required when performing the verification procedure for test methods where volumetric expansion determinations are required. CGA C-1 - 7.3.2(b) states – Attach a suitable liquid-filled pressure vessel to the test system (i.e., a cylinder with a rated working pressure covering the highest proof test pressure to be encountered). This vessel provides a “volume” against which to pump. The question is – Does the cylinder used to calibrate a Proof Pressure system need to have a serial number that is recorded on the calibration / test records? Or is that only required for Water Jacket & Direct Expansion testing? Thank you for any information that you can give me. Brick Keltner, Koorsen Fire & Security#

Page 21200 New Jersey Avenue, SE Washington, DC 20590 U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration July 27, 2026 Brick Keltner Corporate Shop Trainer Koorsen Fire & Security 2820 N. Webster Indianapolis, IN 46219 Reference No. 26-0052 Dear Mr. Keltner: This letter is in response to your April 27, 2026 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the recordkeeping requirements for cylinder requalification. Specifically, you ask whether the requirement in § 180.215(b)(1) to record the serial number of the cylinder used to calibrate a proof pressure system applies to proof pressure testing, or only to volumetric expansion testing. No. A “calibrated cylinder” (see CGA Pamphlet C-1 2016, Methods for Pressure Testing Compressed Gas Cylinders, Sections 3.2.7 and 5.4) is a specially designed cylinder with known expansion values. A “calibrated cylinder” is used to demonstrate integrity of test systems used to determine volumetric expansion (e.g., the water jacket method). As defined in § 180.203, a “proof pressure test” is performed by interior pressurization without the determination of a cylinder’s expansion, and thus, there is no need for a “calibrated cylinder.” Therefore, recording a calibrated cylinder’s serial number is not required for proof pressure test records. According to CGA C-1, Section 7.3.2, a liquid-based proof pressure test system is verified by attaching a standard cylinder with a rated working pressure that covers the highest proof test pressure expected during the day’s testing. The cylinder used in the system verification is not required to be a calibrated cylinder. However, to demonstrate compliance with the verification requirement in CGA C-1, Section 7.3.2, a facility must document the standard cylinder used during the daily system check. Maintaining a record of the standard cylinder’s serial number and rated working pressure is necessary to verify that the cylinder meets the minimum pressure requirements for that day’s testing.#

Page 3The system verification includes the use of a reference gauge or a master gauge. Calibration requirements for all components of the system (pressure indicating device, master gauge, reference gauge) must be periodically calibrated in accordance with Appendix B of CGA Pamphlet C-1. For all calibrated devices, the certificate of calibration shall be maintained on file at the facility. 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#