Interpretation Response #26-0094
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Pacific Gas & Electric Company
Individual Name: Greg Dahl
Location State: CA Country: US
View the Interpretation Document
Response text:
October 13, 2026
Greg Dahl
Pacific Gas & Electric Company
49 Damron Road
PO Box 48
Bangor, CA 95914
Reference No. 26-0094
Dear Mr. Dahl:
This letter is in response to your July 14, 2026 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the installation of pressure relief devices (PRDs) tested prior to when an MC 338 cargo tank motor vehicle (CTMV) is pressure tested. You describe a scenario in which a set of PRDs were tested in February 2026 for installation on a specification MC 338 CTMV. You state that the CTMV was due for its 5-year pressure test and inspection in March 2026; however, the pressure test and inspection, and PRD installation, could not be completed until June 2026. You also note that the final inspection report was completed in July 2026. Specifically, you ask whether the next requalification (retest) date is determined based on June 2026 even though the PRDs intended for installation were tested in February 2026.
Yes. The requalification (retest) date is determined from the most recent inspection or CTMV certification as outlined in § 180.407(c) such as performance of the required pressure test. The HMR do not necessarily require that PRD testing and the pressure test coincide. Only that when performing the pressure test of a cargo tank all self-closing PRDs must be removed and inspected and those not tested or failing tests must be repaired or replaced (see § 180.407(g)(1)).
Thus, in accordance with § 180.415, the cargo tank must be marked with the date (month and year) the pressure test was performed.
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