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Interpretation Response #13-0133

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

Interpretation Response Details

Response Publish Date: 10-22-2013
Company Name: Tytal    Individual Name: Mr. Ing Fernando Giaza
Country: MX

View the Interpretation Document

Response text:

October 22, 2013

Ing. Fernando Garza
Direccion Tecnica
Cadereyta Jimenez, N.L.

Ref. No. 13-0133

Dear Mr. Garza:

This is in response to your letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR 171-180) applicable to DOT 407 cargo tank design criteria.  Specifically, you ask whether your ring stiffener design meets the circumferential reinforcement regulations prescribed in 49 CFR 178.345-7(d).  The pictures you provide of your design show a 1.5 inch gap in the ring stiffeners at the six o’clock position that will be used for drainage.

The answer to your question is no.  As provided by the introductory text in § 178.345-7(d), when a ring stiffener is also used as a circumferential reinforcement member, whether internal or external, reinforcement must be continuous around the circumference of the cargo tank shell.  
I trust this information is helpful.  Please contact us if you require further assistance.


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


Regulation Sections

Section Subject
§ 178.345-7 Circumferential reinforcements