Interpretation Response #11-0055 ([Railroad Commission of Texas] [Mr. James Osterhaus])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Railroad Commission of Texas
Individual Name: Mr. James Osterhaus
Location State: TX Country: US
View the Interpretation Document
Response text:
September 13, 2011
Mr. James Osterhaus
Railroad Commission of Texas
1701 N. Congress
Austin, TX 78711
Ref. No.: 11-0055
Dear Mr. Osterhaus:
This responds to your March 3, 2011 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to MC 331 cargo tanks. Specifically, you ask if the HMR permit the use of an excess flow valve and a manual shutoff valve instead of an internal self-closing stop valve for MC 331 tanks with vapor or liquid discharge openings greater than 1 ¼ NPT, but have been modified using a bushing to reduce the opening to less than 1 ¼ NPT.
Under the HMR, an internal self-closing stop valve is not required for an MC 331 tank if the vapor or liquid discharge opening is less than 1 ¼ NPT (National Pipe Thread) and is equipped with an excess flow valve together with a manually operated external stop valve (§ 178.337-8(a)(5)(i)). However, a change to the size of the opening on an MC 331 cargo tank is considered a modification to the cargo tank and must satisfy all of the requirements of the HMR that apply to cargo tank modification. Accordingly, the modification must be performed by a repair facility holding a valid National Board Certificate of Authorization for use of the National Board "R" stamp (§ 180.413(a)(1)), and the design of the modified cargo tank motor vehicle must be certified in writing by a Design Certifying Engineer as meeting the structural integrity and accident damage protection requirements of the applicable specification (§ 180.413(d)(1)). Also, the person performing the modification must be registered with the Federal Motor Carrier Safety Administration in accordance with Part 107, Subpart F (§ 180.413(a)(3)).
I trust this satisfies your inquiry. Please contact us if we can be of further assistance.
Sincerely,
Ben Supko
Acting Chief, Standards Development Branch
Standards and Rulemaking Division
178.337-8, 180.413