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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 #22-0121

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

Interpretation Response Details

Response Publish Date:

Company Name: DOT Training Solutions

Individual Name: Arturo Prado

Location State: TX Country: US

View the Interpretation Document

Response text:

February 2, 2023

Arturo Prado
DOT Training Solutions
701 Briar Court
Brownsville, TX  78521

Reference No. 22-0121

Dear Mr. Prado:

This letter is in response to your November 4, 2022, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the configuration of bulk trailer valves. You ask whether a DOT 407 cargo tank motor vehicle (CTMV), manufactured as a "wheels back" vehicle, as defined in 49 CFR § 393.5, fitted with a rear loading valve located behind the fifth axle, and in full tow configuration is required to have an internal self-closing stop valve with a sacrificial device.

According to § 178.345-8 and when solely considering accident damage protection, an internal self-closing stop-valve with a sacrificial device is required only when seeking relief from § 178.3458(b)(1). When a sacrificial device is required, it is subject to the strength and location requirements found in § 178.345-8(b)(2). However, based on the photographs and information you provided, we are unable to make the determination whether the configuration presented meets the requirements of § 178.345-8(b)(1) or § 178.345-8(b)(2). Additionally, the CTMV is still subject to the remaining requirements found in § 178.345-8, as well as any other applicable requirements (i.e., tank outlet requirements found in § 178.345-11). These other requirements must also be taken into consideration when making a final determination for valve requirements.

Please note, this office does not make the determination whether specific individual configurations meet the applicable requirements of the HMR.

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

178.345-8, 178.3458(b)(1), 178.345-8(b)(2), 178.345-11

Regulation Sections

Section Subject
178.345-11 Tank outlets
178.345-8 Accident damage protection