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Interpretation Response #16-0115

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

Interpretation Response Details

Response Publish Date: 08-10-2016
Company Name: The Dow Chemical Company    Individual Name: Mr. John Heater
Location state: PA    Country: US

View the Interpretation Document

Response text:

August 10, 2016

Mr. John Heater
Transportation Safety and Security Specialist
The Dow Chemical Company
100 Independence Mall West
Philadelphia, PA 19106

Ref. No. 16-0115

Dear Mr. Heater:

This responds to your June 29, 2016, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR parts 171-180) applicable to the use of stainless steel as a material of construction for DOT Specification 117 (DOT-117) tank cars.  On May 8, 2015, the Pipeline and Hazardous Materials Safety Administration (PHMSA) published HM-251, a Final Rule titled “Hazardous Materials: Enhanced Tank Car Standards and Operation Controls for High-Hazard Flammable Trains” [80 FR 26643] which adopted prescriptive, performance, and retrofit standards for DOT-117 tank cars.  Your questions are paraphrased and answered below:

Q1.  You note that in accordance with DOT-117 prescriptive standards the only material of construction authorized is AAR TC-128 Grade B, normalized steel and ask if any alternate materials, such as stainless steel, may be used when building DOT-117 tank cars.

A1.  The answer is yes.  Section 179.202-1 requires that each DOT-117 tank car be built in accordance with the general requirements of § 179.200 and the prescriptive standards in
§§ 179.202-1 through 179.202-11 or the performance standards in § 179.202-12.  The prescriptive standards for DOT-117 tank cars require the use of, at a minimum, 9/16 inch AAR TC-128, Grade B, normalized steel.  While no other materials are prescribed, alternate designs will be considered in accordance with the performance specification standards of
§ 179.202-12.  This may allow a DOT-117 tank car to be built with stainless steel.  DOT-117 performance standards were intentionally incorporated into HM-251 to drive innovation and allow for variations in the DOT-117 tank car specifications.  

Q2.  You ask how to proceed in an obtaining an approval to build a stainless steel DOT-117 tank car.

A2.  In order for a DOT-117 tank car to be built with stainless steel, it must meet the performance standards outlined in § 179.202-12 (see A1).  Section 179.202-12(a) requires tank car design, testing, and modeling results be reviewed and approved by the Associate Administrator for Railroad Safety/Chief Safety Officer, Federal Railroad Administration (FRA), 1200 New Jersey Ave. S.E., Washington, DC 20590.

Q3.  You ask for consideration in adopting stainless steel as a prescribed material of construction for DOT-117 tank cars and provide reasons for its incorporation.  

A3.  As mentioned in A1 above, the performance standards in § 179.202-12 have been designed to allow for variations in the DOT-117 tank car, as you suggest.

I trust this satisfies your inquiry.  Please contact us if we can be of further assistance.


Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

179.202-1, 179.202-12, 179.200, 179.202-1, 179.202-11

Regulation Sections

Section Subject
§ 179.202-11 Individual specification requirements