# Truck Trailer Manufacturers Association — Hazardous Materials Safety Interpretation - **operation:** document - **citation:** 21-0007 - **title:** Truck Trailer Manufacturers Association — Hazardous Materials Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 2021-04-13 - **effective on:** Not available - **summary:** 21-0007 response to Truck Trailer Manufacturers Association concerning 178.345. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0007.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0007.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0007 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/74891/210007.pdf **body:** <<>> U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 April 13, 2021 John Freiler Engineering Manager Truck Trailer Manufacturers Association 7001 Heritage Village Plaza Suite 220 Gainesville, VA 20155 Reference No. 21-0007 Dear Mr. Freiler: This letter is in response to your January 27, 2021, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the requirements for installing lightweight attachments to a cargo tank motor vehicle. Specifically, you ask about the requirements in § 178.345-3(f)(2) and whether the term “lightweight attachment” is limited exclusively to a conduit clip, brake line clip, skirting structure, lamp mounting bracket, or placard holder. The answer is no. In accordance with § 178.345-3(f)(2), a “lightweight attachment” to a cargo tank wall such as a conduit clip, brake line clip, skirting structure, lamp mounting bracket, or placard holder must be of a construction having lesser strength than the cargo tank wall materials and may not be more than 72 percent of the thickness of the material to which it is attached. The words “such as” used in § 178.345-3(f)(2) denotes that a conduit clip, brake line clip, skirting structure, lamp mounting bracket, and placard holder are all examples of a lightweight attachment. <<>> The examples are not an exhaustive list; however, these types of items are constructed to have lesser strength than the cargo tank wall materials and be not more than 72 percent of the thickness of the material to which it is attached. I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, Dirk Der Kinderen Chief, Standards Development Branch Standards and Rulemaking Division <<>> Ciccarone From: INFOCNTR (PHMSA) To: Subject: Date: Attachments: Dodd, Alice (PHMSA); Hazmat Interps FW: TTMA Request for interpretation on Appurtenances on Cargo Tanks Friday, January 29, 2021 11:24:30 AM TTMA RFI - PHMSA Appurtenances - Final.pdf 21-0007 Dear Alice, Please see the attached request for a letter of interpretation. Please contact our office with any questions. Thank you, Sarah (HMIC) From: John Freiler [mailto:John@trucktrailer.org] Sent: Wednesday, January 27, 2021 2:35 PM To: PHMSA HM InfoCenter Cc: PHMSAPetions@dot.gov; Carrie Renuart ; Jeff Sims ; Michael Stevens Subject: TTMA Request for interpretation on Appurtenances on Cargo Tanks CAUTION: This email originated from outside of the Department of Transportation (DOT). Do not click on links or open attachments unless you recognize the sender and know the content is safe. Hello, Please see the attached letter requesting an interpretation on appurtenances on cargo tanks. Thank you. John Freiler - Engineering Manager Truck Trailer Manufacturers Association 7001 Heritage Village Plaza Suite 220 Gainesville, VA 20155-3094 703-549-3010 - Phone - **truncated:** false - **body characters:** 3091