Arthur L. Fleener — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 June 29, 2020 Arthur L. Fleener Fleener Consulting LLC 3741 Mathews Road Ames, IA 50014 Reference No. 20-0038 Dear Mr. Fleener: This letter is in response to your April 29, 2020, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to MC 331 cargo tanks. Specifically, you seek clarification regarding external visual inspections of MC 331 cargo tanks that have been treated on the lower 1/3 of the cargo tank with a product commonly known as “rock guard.” You note that, similar to paint, “rock guard” is sprayed directly onto the unpainted cargo tank to provide a tough and scratch resistant surface that protects the cargo tank from rust and corrosion. We have paraphrased and answered your questions as follows: Q1. You ask whether an MC 331 cargo tank that has been treated with “rock guard” would require a yearly internal visual inspection as part of the external visual inspection. A1. Section 180.407(d)(1) states, “If external visual inspection is precluded because any part of the cargo tank wall is externally lined, coated, or designed to prevent an external visual inspection, those areas of the cargo tank must be internally inspected.” Therefore, if any portion of a cargo tank is covered with an external lining (e.g., a vinyl wrap) and/or coated (e.g., with paint or rock guard) in such a manner that prevents the proper external visual inspection as described in § 180.407(d)(1), then an internal visual inspection of those areas affected by the paint and/or coating would be required in conjunction with the external visual inspection for the remaining areas of the cargo tank wall. Q2. If the answer to Q1 is yes, you ask how an MC 331 cargo tank treated with “rock guard” is different than a regular painted cargo tank. A2. As stated in A1, if a cargo tank wall is externally lined, coated, or designed to prevent an external visual inspection, those areas of the cargo tank must be internally inspected. As a result, for the purposes of performing the external visual inspection as described in § 180.407(d), both paint and “rock guard” are regarded as coatings and prompt an internal inspection on cargo tanks when they prevent an external inspection.#

Page 2Q3. You ask whether a cargo tank that has been treated with “rock guard” and that is required to have a yearly internal visual inspection as part of the external visual inspection would still require the internal visual inspection if the “rock guard” was not applied to the welded joints. A3. Please see A1 and A2. 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#

Page 3Ballengee 20-0038 From: Foster, Glenn (PHMSA) To: Dodd, Alice (PHMSA) Subject: FW: Request for guidance Date: Wednesday, April 29, 2020 10:13:24 AM Attachments: rock guard interp request.pdf From: art fleener [mailto:fleenerconsulting@yahoo.com] Sent: Wednesday, April 29, 2020 9:53 AM To: Foster, Glenn (PHMSA) <Glenn.Foster@dot.gov> Cc: Kelley, Shane (PHMSA) <shane.kelley@dot.gov> Subject: Request for guidance Glenn See the attached file for a guidance request on external visual inspections for a cargo tank. If you have any questions please let me know. Thanks art Fleener Consulting LLC. 515 291 9208 fleenerconsulting.com#

Page 4DOT Hozordous Moteriols Consulting Emoil : fleenerconsulting@yohoo.com Website: fleenerconsulting.com 3741 Mothews Rd Ames, lowo 500.14 515 -291-9208 CONSULTING LLC April29,2020 Mr. T. Glenn Foster Chief, Regulatory Review and Reinvention Branch Standards and Rulemaking Division Dear Mr. Foster: We would like to seek clarification regarding external visr-ral inspections on MC 331 cargo tanks that have what is commonly known as "rock guard" sprayed on the lower l/3 of cargo tank. Rock guard is a treatment that is sprayed on the cargo tank not unlike paint. Rock guard provides a tough and scratch resistance surface and protects the tank from rust and corrosion. Rock guard is sprayed directly onto the unpainted cargo tank. T'he rest of the cargo tank is painted as normal. We are seeking guidance if cargo tanks that have the rock guard treatment requires an internal visual inspection as part of the external visual inspection. Our tlrickness testing of the spray on rock guard shows that it has a thickness of between 9 rnm and l3 mm. Our thickness testing of the paint commonly used on MC 331 cargo tanks shows that the paint is between l6 mrn and I 8 rnrn thick. Based on our experience if there is corrosion under the rock guard a rust bubble will be visible similar to a rust bubble under paint. It is not uncornmon to have a minimum shell thickness for these tanks of over 0.40 inches. If there is corrosion between the rock guard and the oargo tank shell, an irrternal visual inspection will not show this corrosion. It is our belief that cargo tanks with treatments like rock guard would simply be tested and inspected as any painted cargo tank would be. 1. For a cargo tank that has rock guard sprayed on the tank, would this treatlrent require the tank to have an internal visual inspection yearly as pafi ofthe external visual inspection?#

Page 5@ FLEENER CONSULTING LLC DOT Hozordous Moteriols Consulting Emoil : fleenerconsulting@yohoo.com Website : f leenerconsulting.com 3741 Mothews Rd Ames, lowo 500.l4 515 -291-9208 2. If the answer is yes to question #l how is this any different then a regular painted tank? 3. I f a tanl< has the rock guard treatrnent and if it is required to have an internal visual annually as part of the external visual inspection if the rock guard was not applied to the welded joints would it still require an internal visual inspection annually? Sincerely, k% Arthur L. Fleener#