{"data":{"id":"us/49-cfr-178.346-2","jurisdiction":"us","citation":"49 CFR 178.346-2","heading":"-2 Material and thickness of material.","body":"The type and thickness of material for DOT 406 specification cargo tanks must conform to § 178.345-2, but in no case may the thickness be less than that determined by the minimum thickness requirements in § 178.320(a). The following Tables I and II identify the specified minimum thickness values to be employed in that determination.\nTable I—Specified Minimum Thickness of Heads (or Bulkheads and Baffles When Used as Tank Reinforcement) Using Mild Steel (MS), High Strength Low Alloy Steel (HSLA), Austenitic Stainless Steel (SS), or Aluminum (AL)—Expressed in Decimals of an Inch After Forming\nMaterial Volume capacity in gallons per inch of length\n14 or less Over 14 to 23 Over 23\nMS HSLA SS AL MS HSLA SS AL MS HSLA SS AL\nThickness .100 .100 .160 .115 .115 .173 .129 .129 .187\nTable II—Specified Minimum Thickness of Shell Using Mild Steel (MS), High Strength Low Alloy Steel (HSLA), Austenitic Stainless Steel (SS), or Aluminum (AL)—Expressed in Decimals of an Inch After Forming 1\nCargo tank motor vehicle rated capacity (gallons) MS SS/HSLA AL\nMore than 0 to at least 4,500 0.100 0.100 0.151\nMore than 4,500 to at least 8,000 0.115 0.100 0.160\nMore than 8,000 to at least 14,000 0.129 0.129 0.173\nMore than 14,000 0.143 0.143 0.187\n1 Maximum distance between bulkheads, baffles, or ring stiffeners shall not exceed 60 inches.","path":["Title 49—Transportation","Subtitle B—Other Regulations Relating to Transportation","CHAPTER I—PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","SUBCHAPTER C—HAZARDOUS MATERIALS REGULATIONS","PART 178—SPECIFICATIONS FOR PACKAGINGS","Subpart J—Specifications for Containers for Motor Vehicle Transportation"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-49.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:34Z","sha256":"cd49fa68f5191f94624d0af1b04b0ce2b8d84c0ba51ad62152efd946f9d4a3a9","source_id":"us-cfr","stale":true,"prev":"us/49-cfr-178.346-1","next":"us/49-cfr-178.346-3"},"notice":"GroundRules: Original legal text. Not legal advice."}