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Interpretation Response #13-0159 ([Albermarle Corporation] [Mr. Brad Thomas])

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

Interpretation Response Details

Response Publish Date:

Company Name: Albermarle Corporation

Individual Name: Mr. Brad Thomas

Location State: LA Country: US

View the Interpretation Document

Response text:

November 6, 2013

Mr. Brad Thomas
Logistics Safety and Security Manager
Albermarle Corporation
451 Florida Street
Baton Rouge, LA   70801

Ref. No. 13-0159

Dear Mr. Thomas:

This responds to your July 30, 2013 request for clarification of the requirements for the modification of the DOT Specification 51 portable tanks under §§ 178.274 and 178.275 of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).   Specifically, you ask if modification of a DOT Specification 51 portable tank is authorized under the HMR. You also reference letter of interpretation Ref. No. 07-0225, indicating that modifications can be made as long as they do not “invalidate the ASME U stamp”.

In your incoming letter, you state that you have a DOT Specification 51 portable tank with an inverted removable dome with a vent connection attached to the side of the dome.  This connection is threaded, and, you express concern it may be accidentally loosened as hoses are connected and disconnected.  You indicate that the use of a flanged connection would enhance the safety of the containers.  To modify this connection, you would need to lower the point at which the vent connection intersects the wall of the inverted dome. You would have to cut off the existing vent connection, patch the hole, and cut a new hole a few inches lower.

Your questions are paraphrased and answered below:

Q1.  Does interpretation letter Ref. No. 07-0225 state that welding and cutting on any part of the DOT Specification 51 portable tank is permitted by a shop having an R stamp?  

A1.  No.  Ref No 07-0225 stated modifications are authorized if they are done in accordance with ASME and do not invalidate the ASME U stamp.

Q2.  What limitations are on modification of these DOT Specification 51 portable tanks?

A2.   Modifications made in accordance with §§ 178.274 and 178.275 that do not invalidate the ASME U stamp requirements are authorized.  Modifications that are not in compliance would require a special permit to install.

Q3.  If the modifications you described in your incoming letter are done in accordance with ASME, would the DOT Specification 51 portable tank still be approved for shipping hazardous materials?

A3. PHMSA does not determine if modifications meet the requirements or violate the ASME U stamp.  An approval agency (§ 107.401) should determine if the modification to the DOT 51 Specification portable tank violates the ASME U stamp.  Ultimately, it is the owner of the packaging’s responsibility to determine compliance with the HMR.

Q4.  If the proposed modification is not allowable, would it be allowable to replace the removable dome with a new dome having the adjusted vent location?  

A4.  It should be noted dome replacement is permitted if the new dome with the adjusted vent location is done in accordance with §§ 178.274 and 178.275 and does not invalidate the ASME U stamp.

I hope this answers your inquiry.  If you need additional assistance, please contact this office at (202) 366-8553.   


Robert Benedict
Chief, Standards Development Branch
Standards and Rulemaking Division

178.274, 178.275

Regulation Sections

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