# Truck Trailer Manufacturers Association — Hazardous Materials Safety Interpretation **Citation:** 16-0042 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2018-06-15 16-0042 response to Truck Trailer Manufacturers Association concerning 178.320, 178.345. ## Document text <<>> of Transportation U.S. Department Pipeline and Hazardous Washington, DC 20590 1200 New Jersey Avenue, SE Administration Materials SafetyR JUN 1 5 2017 John Freiler Truck Trailer Manufacturers Association Suite 220 7001 Heritage Village Plaza Gainesville, VA 20155 Reference No. 16-0042 Dear Mr. Freiler: This letter is in response to your March 10, 2016, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the manufacture of Department of Transportation (DOT) specification cargo tanks. Specifically, you ask PHMSA to reconsider whether accident damage protection devices specified in § 178.345-8 (applicable to DOT 406, DOT 407, and DOT 412 cargo tanks) are considered structural support members as 15-0049. opposed to appurtenances as stated in our guidance issued July 17, 2015, under Reference No. Our previously issued guidance on this issue remains valid. An accident damage protection device meets the definition of an appurtenance as defined in §§ 178.320 and 178.345-1. If required, accident damage protection devices for DOT 406, DOT 407, and DOT 412 cargo tanks must be attached to the cargo tank in accordance with the requirements of § 178.345-8(a)(3). If accident damage protection is applied directly to the cargo tank wall, the accident damage protection device must have no lading retention or containment function and provide no structural support to the cargo tank. Accident-induced stresses resulting from the appropriate accident damage protection device requirements in combination with the stresses from the cargo tank operating at the maximum allowable working pressure (MAWP) may not result in a cargo factor of 1.3. tank wall stress greater than the ultimate strength of the material of construction using a safety I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, T. Glenn Foster Standards and Rulemaking Division Chief, Regulatory Review and Reinvention Branch <<>> Stevens 178.345 Goodall, Shante CTR (PHMSA) Aocident clamaxe protecem Sent: From: Geller, Shelby CTR (PHMSA) 16-0042 To: Thursday, March 10, 2016 5:05 PN Subject: lazmat Interps Attachments: FW: Letter of Interpretation Ref. No: 15-0049 PHMSA Accident Protection Response.pdf Dear Shante and Alice, Forwarded is a request for a formal letter of interpretation. Thanks, Shelby From: John Freiler [mailto:john@ttmanet.org] Sent: Thursday, March 10, 2016 2:48 PM To: PHMSA HM InfoCenter Subject: Letter of Interpretation Ref. No: 15-0049 Cc: Staniszewski, Stanley (PHMSA); Pfund, Duane (PHMSA); Carrie Renuart; Jeff Sims; Nancy Livingston Dear Sirs, Please see the attached letter which asks PHMSA to reconsider the interpretation given in Ref. No: 15-0049 which if allowed to stand would render almost all cargo tanks currently in service as out of compliance with the Hazardous Materials Regulations. Please feel free to contact me if you have any questions. Regards, John Freiler - Engineering Manager TTMA TTMAnet.org RUCK TRAILER Manufacture rillall Associati Truck Trailer Manufacturers Association Since 1941 7001 Heritage Village Plaza Suite 220 Gainesville, VA 20155-3094 703-549-3010 - Phone - DO NOT RETRACT 15-0049 - ADD CLARIFY LANGUAGE 1 <<>> Stevens 178,345 Goodall, Shante CTR (PHMSA) accident damase potedam. From: Geller, Shelby CTR (PHMSA) 16-0042 Sent: Thursday, March 10, 2016 5:05 PM To: Subject: Hazmat Interps Attachments: FW: Letter of Interpretation Ref. No: 15-0049 PHMSA Accident Protection Response.pdf Dear Shante and Alice, Forwarded is a request for a formal letter of interpretation. Thanks, Shelby From: John Freiler [mailto:john@ttmanet.org] Sent: Thursday, March 10, 2016 2:48 PM To: PHMSA HM InfoCenter Subject: Letter of Interpretation Ref. No: 15-0049 Cc: Staniszewski, Stanley (PHMSA); Pfund, Duane (PHMSA); Carrie Renuart; Jeff Sims; Nancy Livingston Dear Sirs, Please see the attached letter which asks PHMSA to reconsider the interpretation given in Ref. No: 15-0049 which if allowed to stand would render almost all cargo tanks currently in service as out of compliance with the Hazardous Materials Regulations. Please feel free to contact me if you have any questions. Regards, John Freiler - Engineering Manager TTMA TRUCK TRAILER Manufacturen TTMAnet.org Since 1941 issociatio Truck Trailer Manufacturers Association 7001 Heritage Village Plaza Suite 220 Gainesville, VA 20155-3094 703-549-3010 - Phone <<>> heary 5178.345. 8(a)(1)(3) acadent damage protestan Dodd, Alice (PHMSA) 15-0049 From: Sent: Ciccarone, Michael CTR (PHMSA) To: Thursday, March 12, 2015 3:00 PM Hazmat Interps Subject: FW: Request for interpretation - Roll Over Guards. Shante/Alice, I'm not seeing this one either. From: Ciccarone, Michael CTR (PHMSA) To: Hazmat Interps Sent: Thursday, January 15, 2015 12:52 PM Subject: FW: Request for interpretation - Roll Over Guards. Shante/Alice, Please submit this for a formal letter of interpretation. Thanks, Mike From: D.L. Thompson [mailto:dlthompson@thompsontank.com To: PHMSA HM InfoCenter Sent: Thursday, January 15, 2015 12:21 PM Subject: Request for interpretation - Roll Over Guards. Gentlemen Q1. Are the Accident Damage Protection Devices or Roll Over Guards specified in DOT 178.348-8 considered to be an Appurtenance / Attachment or a Structural Support Member, DOT 178.345-8 (a) (1) (3) requires that the accident induced stresses transferred to the tank shell with the tank operating at the MAWP be considered. Note: ASME considers these guards or devices to be an attachment and also requires that these stresses be considered. Thank you for your consideration. David I Thompson PO Box 790 Lakewood, CA. 90714 Thompson Tank, Inc. 8029 Phlox Street, Downey, CA 90241 Phone 562-869-7711 Fax 562-869-7214 Toll Free 800-421-7545 1 <<>> U.S. Department of Transportation Safety Administration Pipeline and Hazardous Materials Washington, DC 20590 1200 New Jersey Avenue, SE Mr. David L. Thompson JUL 1 7 2015 Thompson Tank, Inc. P.O. Box 790 Lakewood, CA 90714-0790 Ref No.: 15-0049 Dear Mr. Thompson: This is a response to your January 15, 2015 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) with regard to the manufacture of DOT specification cargo tanks. Specifically you ask if accident damage protection devices specified in § 178.345-8 (applicable to DOT 406, DOT 407 and DOT 412 cargo tanks) are considered an appurtenance or a structural support member. An accident damage protection device meets the definition of an appurtenance as defined in §§ 178.320 and 178.345-1. An accident damage protection device does not itself have lading retention or containment function and provides no structural support to the cargo tank. Accident damage protection devices if required for DOT 406, DOT 407 and DOT 412 cargo tanks must be attached to the cargo tank in accordance with the requirements of § 178.345-8(a)(3). Accident induced stresses resulting from the appropriate accident damage protection device requirements in combination with the stresses from the cargo tank operating at the MAWP may not result in a cargo tank wall stress greater than the ultimate strength of the material of construction using a safety factor of 1.3. I trust this information is helpful. If you have further questions, please do not hesitate to contact this office. Sincerely, Diane APF1 Duane A. Pfund International Standards Coordinator Standards and Rulemaking Division <<>> TTMA RICK TRAILER Manufacturer Tank Conference ASSOCIaTO TTMAnet.org Since 1941 Jeffrey M. Sims • President 7001 Heritage Village Plaza • Suite 220 • Gainesville, VA 20155 • 703-549-3010 March 10, 2010 U.S. DOT PHMSA Office of Hazardous Materials Standards Attn: PHH-10 East Building 1200 New Jersey Avenue, SE. Washington, DC 20590-0001 phmsa.hm-infocenter@dot.gov Re: Letter of Interpretation Ref No: 15-0049 (Copy Attached) Dear Sirs, We recently had this interpretation come to our attention. It appears that it was not fully thought through, and we would ask that it be reconsidered. The interpretation in question mistakenly qualifies accident damage protection devices as specified in §178.345-8 as an appurtenance as defined in §§ 178.320 and 178.345-1. The specific issue we feel is incorrect is in the "provides no structural support to the cargo tank" finding. It appears that PHMSA failed to consider the full implications of the defining accident damage protection devices as appurtenances. While the letter correctly conveys the requirement to deal with accident induced stresses into the cargo tank wall contained in §178.345-8(a)(3), it apparently neglects to deal with the additional requirements for appurtenances that the redefining would cause: §178.345-3(f)(3) requires that appurtenances be attached with pads two inches larger than the appurtenance. It is this requirement that is the problem. Virtually none of the cargo tanks in service utilize appurtenance-style pads under their accident damage protection devices. Stresses are tracked according to the requirements for accident damage protection devices, but cargo tank designers seldom need a pad or if they do, they don't need one that meets the 2" set back rule. This means that this letter of interpretation, if allowed to stand, would make nearly all cargo tanks currently in service as out of compliance with the HMR; something we believe was inadvertent. <<>> Further, we find evidence in the code that indicates that accident damage protection devices were not intended to be classified as appurtenances: §178.345-3(f)(1) reads "Structural members, the suspension sub- frame, accident protection structures and external circumferential reinforcement devices must be used as sites for attachment of appurtenances and other accessories to the cargo tank, when practicable." [Emphasis added]. Please review the letter and retract it immediately; the definition of appurtenance refers to structural support and we believe that accident damage protection devices do provide structural support to the cargo tank for specific emergency loading cases and therefore do not meet the definitions in the code as written. Sincerely, John Freiler Engineering Manager CC: Duane A Pfund • Stan Staniszewski ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `abbd21758c500104907c531514ebae80123ad1143a14223b10a3985f604f06b3` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-23T09:44:45.159Z - Document slug: `phmsa-interpretation-16-0042` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Truck Trailer Manufacturers Association" ], "individuals": [ "John Freiler" ], "refIds": [ "16-0042" ], "catalogDates": [ "2018-06-15" ], "catalogParts": [ 178 ], "catalogRowCount": 2, "sourceRecordUrls": [ "https://www.phmsa.dot.gov/node/70531" ], "linkedAttachmentUrls": [], "unavailableResponseUrls": [], "duplicateRepresentationUrls": [], "citedSections": [ "178.320", "178.345", "178.348" ], "catalogPageUrls": [ "https://www.phmsa.dot.gov/regulations/title49/section/178320", "https://www.phmsa.dot.gov/regulations/title49/section/178345-8" ], "pdfUrls": [ "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/58476/160042.pdf" ], "representations": [ { "viewUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/58476/160042.pdf", "detailUrl": null, "detailHtmlPath": null, "pdfUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/58476/160042.pdf", "pdfArtifactPath": "data/sources/phmsa-interpretations/16-0042-a7b32d92e2.pdf", "pdfArtifactSha256": "29944fa934368174478e09abb9487229ff0968c2850e79bbed9c73670de4098a", "extractedTextPath": "data/sources/phmsa-interpretations/16-0042-a7b32d92e2.v2.txt", "extractedTextSha256": "1a31132978ab2787d1ee07dc23befcd4602d05a17dcf76019890e6d7e0a85df5", "pageCount": 7, "extractionVersion": 2 } ], "caveat": "Interpretations apply regulations to the facts presented and do not create independently enforceable requirements.", "jurisdiction": "US" } ```