You are here

Interpretation Response #13-0207R


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

Interpretation Response Details

Response Publish Date: 08-22-2014
Company Name: Thompson Tank, Inc.    Individual Name: Mr. Thompson
Location state: CA    Country: US

View the Interpretation Document


Response text:

8/22/2014

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

Ref No.: 13-0207R

Dear Mr. Thompson:

This is in reference to the PHMSA response to your request for interpretation Ref. No. 13-0207 of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) issued to you on February 18, 2014. After further consideration Ref. No. 13-0207 has been superseded by this revised letter.

In your original letter you request clarification in regard to the manufacture of DOT specification cargo tanks. Specifically, you question whether it is permissible to manufacture a DOT 407, DOT 412, or dual specification DOT 407/412 cargo tank for vacuum loading without being constructed and certified in accordance with the Section VIII of the ASME Code for an external design pressure of at least 15 psig.

In accordance with the general design and construction requirements applicable to cargo tanks, in § 178.345-1(f), each DOT 412 cargo tank with a MAWP greater than 15 psig, and each DOT 407 cargo tank with a MAWP greater than 35 psig must be constructed and certified in conformance with Section VIII of the ASME Code, except as limited or modified by the applicable cargo tank specification.

Specification DOT 412 cargo tanks designed to be loaded by vacuum must have a minimum external MAWP of 15 psig and a minimum internal MAWP of 25 psig in accordance with § 178.348-1(c). Any DOT 412 cargo tank with a MAWP greater than 15 psig must be designed, constructed and certified in conformance with Section VIII of the ASME Code per § 178.348-1(e)(1).

Specification DOT 407 cargo tanks designed to be loaded by vacuum must have a minimum external design pressure of 15 psig and must be designed, constructed and certified in accordance with Section VIII of the ASME Code, in accordance with § 178.347-1(c). Therefore, a DOT 407 cargo tank designed for vacuum loading would not be permitted to be manufactured without being constructed and certified in accordance with Section VIII of the ASME Code.

A cargo tank built to a dual specification DOT 407/412, designed to be loaded by vacuum, must conform to both of the applicable specifications. Therefore since all DOT 407 and DOT 412 cargo tanks designed for vacuum loading must be constructed and certified in accordance with Section VIII of the ASME Code and have a minimum external design pressure of 15 psig, the manufacture of this multi-specification cargo tank would not be permitted without fulfilling these requirements.

I hope this information is helpful and apologize for any inconvenience this may have caused. If you have any more questions, please do not hesitate to contact this office.

Sincerely,

Robert Benedict
Chief, Standards Development
Standards and Rulemaking Division

178.345-1(f), 178.347-1(c), 178.348-1(c)


Regulation Sections

Section Subject
§ 178.345 General design and construction requirements applicable to Specification DOT 406 (178.346), DOT 407 (178.347), and DOT 412 (178.348) cargo tank motor vehicles