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Interpretation Response #15-0049 ([Thompson Tank, Inc.] [Mr. David Thompson])

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

Interpretation Response Details

Response Publish Date:

Company Name: Thompson Tank, Inc.

Individual Name: Mr. David Thompson

Location State: CA Country: US

View the Interpretation Document

Response text:

July 17, 2015

Mr. David L. Thompson
Thompson Tank, Inc.
P.O. Box 790
Lakewood, CA 90714-0790

Ref No.: 15-0049

Dear Mr. Thompson:

This is a response to your January 15, 2015 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) with regard to the manufacture of DOT specification cargo tanks. Specifically you ask if accident damage protection devices specified in § 178.345-8 (applicable to DOT 406, DOT 407 and DOT 412 cargo tanks) are considered an appurtenance or a structural support member.

An accident damage protection device meets the definition of an appurtenance as defined in §§ 178.320 and 178.345-1. An accident damage protection device does not itself have lading retention or containment function and provides no structural support to the cargo tank. Accident damage protection devices if required for DOT 406, DOT 407 and DOT 412 cargo tanks must be attached to the cargo tank in accordance with the requirements of § 178.345-8(a)(3). Accident induced stresses resulting from the appropriate accident damage protection device requirements in combination with the stresses from the cargo tank operating at the MAWP may not result in a cargo tank wall stress greater than the ultimate strength of the material of construction using a safety factor of 1.3.

I trust this information is helpful. If you have further questions, please do not hesitate to contact this office.



Duane A. Pfund
International Standards Coordinator
Standards and Rulemaking Division

178.320, 178.345-1, 178.345-8(a)(3)

Regulation Sections

Section Subject
178.320 General requirements applicable to all DOT specification cargo tank motor vehicles
178.345-1 General requirements
178.345-8 Accident damage protection