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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #22-0111

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: State Industrial Products

Individual Name: Travis Arledge

Location State: OH Country: US

View the Interpretation Document

Response text:

January 17, 2023

Travis Arledge
Packaging & Equipment Engineer
State Industrial Products
383 North High Street
Hebron, OH 43025

Reference No. 22-0111

Dear Mr. Arledge:

This letter is in response to your October 26, 2022, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to hydrostatic pressure testing of non-bulk packagings. Specifically, you indicate that you have plastic pails—used for shipments of "UN1824, Sodium hydroxide solution, 8, PG II"—rated to a test pressure of 20 kPa, which is more than the required hydraulic test pressure calculated for the specific hazardous material, as prescribed in § 178.605(d)(1). You believe this to be compliant with the HMR but inquire whether the packagings must instead be rated to a minimum test pressure of 100kPa, as is prescribed in §§ 178.605(d)(2) or (3).

The answer is no. Section 178.605(d) provides three options for determining the test pressure to be applied when performing hydrostatic pressure testing. When using the method specified in § 178.605(d)(1), the test pressure must not be less than the total gauge pressure measured in the packaging (i.e., the vapor pressure of the filling material and the partial pressure of the air or other inert gas minus 100 kPa (15 psi)) at 55 °C (131 °F), multiplied by a safety factor of 1.5. This total gauge pressure must be determined on the basis of a maximum degree of filling in accordance with § 173.24a(d) of the HMR and a filling temperature of 15 °C (59 °F). Section 178.605(d)(1) does not specify a minimum test pressure of 100 kPa similar to paragraphs (d)(2) or (d)(3).

I hope this information is helpful. Please contact us if we can be of further assistance.


Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

178.605(d)(1), 178.605(d)(2) or (3)

Regulation Sections

Section Subject
178.605 Hydrostatic pressure test