# Transport Canada, Ontario Region — Hazardous Materials Safety Interpretation - **operation:** document - **citation:** 21-0020 - **title:** Transport Canada, Ontario Region — Hazardous Materials Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 2021-10-22 - **effective on:** Not available - **summary:** 21-0020 response to Transport Canada, Ontario Region concerning 180.605. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0020.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0020.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0020 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/76056/210020.pdf **body:** <<>> U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 October 22, 2021 Mr. Brent Grice Dangerous Goods Inspector Transport Canada, Ontario Region 4900 Yonge Street-3rd Floor North York, Ontario M2N 6A5 Canada Reference No. 21-0020 Dear Mr. Grice: This letter is in response to your March 2, 2021, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to rejection criteria during the inspection of Department of Transportation (DOT) Specification 51 portable tanks. We have paraphrased and answered your questions as follows: Q1. You ask what the rejection criteria is for a DOT Specification 51 portable tank should a reduction in wall thickness be found during an inspection. A1. If a DOT Specification 51 portable tank is found to have a reduction in wall thickness during an inspection and it is verified by appropriate measurement, the wall thickness may not fall below the minimum thickness (i.e., the manufactured thickness minus any applicable corrosion allowance). If it does, the inspector may determine such findings to be evidence of an “unsafe condition.” Q2. You ask how a person should determine the minimum thickness of a DOT Specification 51 portable tank since the minimum thickness is not required to be marked on the name plate. A2. If a DOT Specification 51 portable tank is not marked with the minimum wall thickness, the thickness listed on the manufacturer’s data report—minus any applicable corrosion allowance—may be used as the minimum thickness of the portable tank. <<>> Q3. You ask whether thickness readings that are below the thicknesses indicated on the manufacturer’s data report—minus any applicable corrosion allowance—meet the rejection criteria of § 180.605(i) as evidence of an “unsafe condition.” A3. The answer is yes. If thickness readings are below the thicknesses indicated on the manufacturer’s data report—minus any applicable corrosion allowance—the inspector may determine such findings to be evidence of an “unsafe condition” in accordance with § 180.605(i). See answer A1. I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, T. Glenn Foster Chief, Regulatory Review and Reinvention Branch Standards and Rulemaking Division <<>> Edmonson 21-0020 From: INFOCNTR (PHMSA) To: Subject: Date: Dodd, Alice (PHMSA); Hazmat Interps FW: Request for Formal Interpretation Tuesday, March 2, 2021 2:08:42 PM Hi Alice, Please see below for a letter of interpretation request. Please contact our office with any questions. Thank you, Sarah (HMIC) From: Grice, Brent [mailto:brent.grice@tc.gc.ca] Sent: Tuesday, March 2, 2021 10:57 AM To: INFOCNTR (PHMSA) Subject: Request for Formal Interpretation 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. Good Morning, I am an inspector with Transport Canada Dangerous Goods and I am trying to seek clarification with respect to Specification 51 portable tanks and the requirements for periodic testing, inspection and repair of portable tanks outlined in 49CFR paragraphs § 180.605(g)(1) & 180.605 (i) § 180.605 (g) (1) states The shell is inspected for pitting, corrosion, or abrasions, dents, distortions, defects in welds or any other conditions, including leakage, that might render the portable tank unsafe for transportation. The wall thickness must be verified by appropriate measurement if this inspection indicates a reduction of wall thickness; § 180.605 (i) states: Rejection criteria. When evidence of any unsafe condition is discovered, the portable tank may not be returned to service until it has been repaired and the pressure test is repeated and passed. The clarification that I am seeking is as follows: 1. What is the rejection criteria to determine if the reduction in wall thickness is worn beyond acceptable limits as 49CFR 180.605(i) is very unclear as it only indicates to be rejected when an unsafe condition is discovered? 2. Nameplates on Specification 51 portable tanks were not required to be marked with a minimum thickness for shells and heads (at least in 49 CFR publications in 1982, 1986, 1992, 1994, 1997). Should the thicknesses listed on the U-1A, manufacturer’s data report, be considered as minimum thicknesses? 3. If the answer to question 2 is no, then what forms the basis for a minimum acceptable thickness for in-service Specification 51 portable tanks? 4. Would thickness readings that are below the thicknesses indicated on the U-1A form minus any corrosion allowance meet the rejection criteria of § 180.605 (i) as evidence of an unsafe condition? I look forward to hearing a response by email or by mail Thanks Brent Brent Grice Dangerous Goods Inspector / Inspecteur-Marchandises Dangereuses Transport Canada / Transports Canada Ontario Region / Region de l'Ontario Telephone | Téléphone: (416) 973-1868 Facsimile | Télécopieur: (416) 973-9907 <<>> TDG-TMDOntario@tc.gc.ca 4900 Yonge Street-3rd Floor, North York, Ontario M2N 6A5 4900 rue Yonge 3ieme etage, North York, ON M2N 6A5 Government of Canada | Gouvernement du Canada - **truncated:** false - **body characters:** 5355