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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #99-0249 ([FMC Corporation] [Mr. Ralph J. Mikida])

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

Interpretation Response Details

Response Publish Date:

Company Name: FMC Corporation

Individual Name: Mr. Ralph J. Mikida

Location State: PA Country: US

View the Interpretation Document

Response text:

August 25, 2000

 

Mr. Ralph J. Mikida                       Ref No. 99-0249
Hazardous Materials Coordinator
FMC Corporation
1735 Market Street
Philadelphia, PA 19103

Dear Mr. Mikida:

I apologize for the delay in responding to your letter concerning the requirement in 49 CFR 173.31 (d)(1)(vi) to carefully inspect a frangible (rupture) disc in a pressure relief device prior to each hazardous material shipment. This requirement has its origins in regulations of the Interstate Cornmerce Commission issued in 1921. The wording of this requirement was most recently revised in a final rule published on September 21, 1995, under RSPA's Docket Nos.  HM- I 75A and 201 (60 Fed.  Reg. 49098).

As the language of § 173.3 1 (d)(1)(vi) states, the purpose of this type of inspection. is to check "for corrosion or damage that may alter the intended operation of the device." For that reason, in response to a comment submitted in a separate rule-makings proceeding under Docket no.  MI-216 (61 Fed.  Reg, 28666,28671; June 5, 1996), we stated in the preamble that RSPA and FRA believe in order to fully inspect a rupture disc (both top and bottom), the disc must be removed from the safety vent device.  It has been FRA’s experience that a rupture disc may appear normal on the top side, but be severely damaged or corroded on the bottom side.

You and others have raised sed concerns about the language of the present rule and its application to persons that forward a loaded tank car received from another location or return a tank car with residue.  We anticipate initiating a rule-makings in the near future to address these concerns.

Sincerely,

 

Edward T. Mazzullo
Director, Office of Hazardous
Materials Standards

173.31

Regulation Sections

Section Subject
173.31 Use of tank cars