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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 #18-0125

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

Interpretation Response Details

Response Publish Date:

Company Name: Truck Trailer Manufacturers Association

Individual Name: John Freiler

Location State: VA Country: US

View the Interpretation Document

Response text:

April 16, 2019

John Freiler
Truck Trailer Manufacturers Association
7001 Heritage Village Plaza, Suite 220
Gainesville, VA  20155

Reference No. 18-0125

Dear Mr. Freiler:

This letter is in response to your October 5, 2018, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the design of MC-331 cargo tanks. Specifically, you ask about the requirements for shear sections on valves.

We have paraphrased and answered your questions as follows:

Q1. You ask if § 178.337-10(f) applies to valves located within a recessed well that meet the accident damage protection requirements on top of an MC-331 cargo tank.

A1. The answer is yes.  Section 178.337-10(f) still applies to valves located on the top of an MC‑331 cargo tank that meet the requirements for accident damage protection.

Q2. You ask if a ball valve without a shear section may be used for liquid and vapor connections within a recessed well on top of an MC-331 cargo tank.

A2. The answer is no.  A shear section is still required. The ball valve and recessed well do not except the cargo tank from the requirements for shear sections on valves.

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

Sincerely,

T. Glenn Foster
Chief, Regulatory Review and Reinvention
Standards and Rulemaking Division

Regulation Sections