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Interpretation Response #19-0131

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

Interpretation Response Details

Response Publish Date:

Company Name: Odfjell

Individual Name: Pat Mentzel

Location State: TX Country: US

View the Interpretation Document

Response text:

May 26, 2020

Pat Mentzel
12211 Port Road
Seabrook, TX  77586

Reference No. 19-0131

Dear Mr. Mentzel:

This letter is in response to your December 4, 2019, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to valve requirements for International Organization for Standardization (ISO) containers or United Nations (UN) portable tanks. In your email, you provided two photographs depicting two different configurations for bottom discharge outlets for a UN portable tank with a valve and cap.

  • Photograph #1 illustrates a UN portable tank with a dry break fitting or coupling.
  • Photograph #2 illustrates a UN portable tank with a traditional external stop-valve.

In your letter, you state that it is your understanding that a UN portable tank must have two valves and a cap for the bottom discharge to be in compliance with the portable tank outlet requirements in § 178.275(d)(3). Additionally, you ask whether the dry break fitting in photograph #1 conforms to the HMR.

A fitting or coupling is an apparatus that allows for the connection of two or more pipes or hoses, and is not considered a "valve" meeting the requirements of the shut-off devices described in § 178.275(d)(3) of the HMR. A fitting/coupling does not contain a lever or any other external manner of activation independent from the act of connecting. However, a fitting/coupling would be acceptable to use if it contained an internal valve with an external means of operation, which met the requirements of § 178.275(d)(3)(ii). It is important to note that the fitting's internal valve, having the ability to start/stop the flow of lading, would meet the HMR requirements and not the fitting itself. Also, this fitting/coupling would not be able to be removed as the shut-off devices would no longer be in series as required.

Furthermore, photograph #1 appears to depict the bottom discharge outlet as containing a dry break fitting/coupling equipped with an internal valve and an external activation lever. If the fitting/coupling meets the requirements described above, this would then meet the requirement of § 178.275(d)(3)(ii) 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

178.275(d)(3), 178.275(d)(3)(ii)

Regulation Sections

Section Subject
178.275 Specification for UN Portable Tanks intended for the transportation of liquid and solid hazardous materials