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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 #21-0043

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

Interpretation Response Details

Response Publish Date:

Company Name: American Bureau of Shipping

Individual Name: Simone Goncalves

Location State: TX Country: US

View the Interpretation Document

Response text:

September 15, 2021

Ms. Simone Goncalves
Technical Manager
American Bureau of Shipping
1701 City Plaza Dr.
Spring, TX 77389

Reference No. 21-0043

Dear Ms. Goncalves:

This letter is in response to your April 19, 2021, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to United Nations (UN) specification portable tanks. Specifically, you ask if a UN portable tank—without an outside framework—can be certified as provided in § 178.274.

A UN portable tank may technically be designed and constructed in accordance with § 178.274 without an "outside framework." As provided in § 171.8, a "UN portable tank" is an intermodal tank with a capacity of more than 450 liters, and includes a shell fitted with service equipment and structural equipment, including stabilizing members external to the shell and skids, mountings, or accessories to facilitate mechanical handling. Additionally, in accordance with § 178.274(h)(1), UN portable tanks must be designed and constructed with a support structure to provide a secure base during transport, taking into account the forces and safety factors specified in paragraphs (c)(1) and (c)(2) of § 178.274. The support structure, or structural equipment, must also adequately protect the shell and service equipment from damage resulting from impact and overturning if the shell and service equipment are not constructed to withstand such forces, as per § 178.274(h)(5). Therefore, while an outside framework is typically used to fulfill design and construction requirements, a UN portable tank without the outside framework would still have to meet all applicable requirements, including those mentioned above.

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

171.8, 178.274, 178.274(h)(1), 178.274(h)(5), 178.274(c)(1), 178.274 (c)(2)

Regulation Sections

Section Subject
171.8 Definitions and abbreviations
178.274 Specifications for UN portable tanks