# Thompson Tank, Inc. — Hazardous Materials Safety Interpretation **Citation:** 13-0207R **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2014-08-22 13-0207R response to Thompson Tank, Inc. concerning 178.345, 178.347, 178.348. ## Document text <<>> of Transportation U.S. Department Materials Safety Pipeline and Hazardous 1200 New Jersey Avenue, SE Washington, D.C. 20590 Administration AUG 2 2 2014 Mr. David L. Thompson Thompson Tank, Inc. P.O. Box 790 Lakewood, CA 90714-0790 Ref No.: 13-0207R Dear Mr. Thompson: This is in reference to the PHMSA response to your request for interpretation Ref. No. 13-0207 of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) issued to superseded by this revised letter. you on February 18, 2014. After further consideration Ref. No. 13-0207 has been In your original letter you request clarification in regard to the manufacture of DOT specification cargo tanks. Specifically, you question whether it is permissible to manufacture a DOT 407, DOT 412, or dual specification DOT 407/412 cargo tank for vacuum loading Code for an external design pressure of at least 15 psig. without being constructed and certified in accordance with the Section VIII of the ASME In accordance with the general design and construction requirements applicable to cargo tanks, in § 178.345-1(f), each DOT 412 cargo tank with a MAWP greater than 15 psig, and each DOT 407 cargo tank with a MAWP greater than 35 psig must be constructed and by the applicable cargo tank specification. certified in conformance with Section VIII of the ASME Code, except as limited or modified Specification DOT 412 cargo tanks designed to be loaded by vacuum must have a minimum external MAWP of 15 psig and a minimum internal MAWP of 25 psig in accordance with § 178.348-1(c). Any DOT 412 cargo tank with a MAWP greater than 15 psig must be § 178.348-1(e)(1). designed, constructed and certified in conformance with Section VIII of the ASME Code per Specification DOT 407 cargo tanks designed to be loaded by vacuum must have a minimum external design pressure of 15 psig and must be designed, constructed and certified in accordance with Section VIII of the ASME Code, in accordance with § 178.347-1(c). Therefore, a DOT 407 cargo tank designed for vacuum loading would not be permitted to be manufactured without being constructed and certified in accordance with Section VIII of the ASME Code. <<>> A cargo tank built to a dual specification DOT 407/412, designed to be loaded by vacuum, must conform to both of the applicable specifications. Therefore since all DOT 407 and DOT 412 cargo tanks designed for vacuum loading must be constructed and certified in accordance with Section VIII of the ASME Code and have a minimum external design pressure of 15 psig, the manufacture of this multi-specification cargo tank would not be permitted without fulfilling these requirements. I hope this information is helpful and apologize for any inconvenience this may have caused. If you have any more questions, please do not hesitate to contact this office. Sincerely, Kht Bilit Robert Benedict Chief, Standards Development Standards and Rulemaking Division 178.345-1(f), 178.347-1(c), 178.348-1(c) <<>> ASME - D.O.T CERTIFICATION THOMPSON TANK, INC. D.O.T. INSPECTION - TESTING DESIGN ENGINEERING • CONSTRUCTION THOMPSON VACUUM-PRESSURE UNITS Suchak $178.347-1(a) 8178.348-(9 October 24, 2013 $180.405FA0 13 OCT U.S. DOT Cargo lanks 25 PHMSA Office of Hazardous Material DOT/RSPA/OHMS Standards 13-0207 Attn: PHH-10 !!NIT East building 1200 New Jersey Ave., SE. Washington, DC 20590-0001 Gentlemen, Is it permissible to manufacture a DOT-407 or a DOT-412, or a Dual Specification DOT-407/DOT-412 Cargo Tank for vacuum loading without external design pressure of at least 15psi? being constructed and certified in accordance with the ASME Code for an Reference: 178.347-10 178.348-1 C 180.405 (f) (1) (i) Sincerely, David L. Thompson Thompson Tank, Inc. MAILING: POST OFFICE BOX 790, LAKEWOOD, CA 90714-0790 SHIPPING: 8029 PHLOX STREET, DOWNEY, CA 90241 PHONE: (562) 869-7711 • FAX: (562) 869-7214 • OUT OF STATE: (800) 421-7545 ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `d125238f91d2f4146de6f063e08c1faf7978b87f2624d9d93699f9cc69955e9a` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-22T04:26:07.369Z - Document slug: `phmsa-interpretation-13-0207r` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Thompson Tank, Inc." ], "individuals": [ "Mr. Thompson" ], "refIds": [ "13-0207R" ], "catalogDates": [ "2014-08-22" ], "catalogParts": [ 178 ], "catalogRowCount": 3, "sourceRecordUrls": [ "https://www.phmsa.dot.gov/node/66011" ], "linkedAttachmentUrls": [], "unavailableResponseUrls": [], "duplicateRepresentationUrls": [], "citedSections": [ "178.345", "178.347", "178.348", "180.405" ], "catalogPageUrls": [ "https://www.phmsa.dot.gov/regulations/title49/section/178345", "https://www.phmsa.dot.gov/regulations/title49/section/178347", "https://www.phmsa.dot.gov/regulations/title49/section/178348" ], "pdfUrls": [ "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2014/130207R.pdf" ], "representations": [ { "viewUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2014/130207R.pdf", "detailUrl": null, "detailHtmlPath": null, "pdfUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2014/130207R.pdf", "pdfArtifactPath": "data/sources/phmsa-interpretations/13-0207r-d59f7afdcb.pdf", "pdfArtifactSha256": "25dd806b82c298a60c3c8a8d5236d9ec89f4aaa267efe73878a06a58a2c605a6", "extractedTextPath": "data/sources/phmsa-interpretations/13-0207r-d59f7afdcb.v2.txt", "extractedTextSha256": "88139f426547f7ed97759bc63aeb6d7282c72c4780155ff8b204dc878f9c9669", "pageCount": 3, "extractionVersion": 2 } ], "caveat": "Interpretations apply regulations to the facts presented and do not create independently enforceable requirements.", "jurisdiction": "US" } ```