Truck Trailer Manufacturers Association — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Washington, D.C. 20590 400 Seventh Street, S.W Special Programs Research and MAY 5 1998 Administration Mr. Donald W. Vierimaa Vice President-Engineering Truck Trailer Manufacturers Association 1020 Princess Street Alexandria, VA 22314 Dear Mr. Vierimaa: This is in response to your letter requesting clarification of your understanding that when - - calculating the static stresses of non-American Society of Mechanical Engineers (ASME) Code stamped DOT 400 series cargo tanks in accordance with § 178.345-3(b), the requirement specified in § 178.345-3(a) (2) is applicable. Your understanding of §§ 178.345-3(a) and (b) is correct. In cases where actual physical property tests of materials are certified showing an actual ultimate tensile strength greater than that shown in the ASME Code or the American Society for Testing and Materials (ASTM) standard, the ultimate tensile strength of the material used in the design may not exceed 120% of the minimum ultimate strength specified in the ASME Code or the ASTM standard. Section 178.345-3(a)(2) is applicable for the calculation of the static stresses of non-ASME DOT 400 series cargo tanks in accordance with §§ 178.345-3(b) and (c). I apologize for the delay in preparing this response and hope that it has not caused you any inconvenience. If you need further assistance, please contact us. Sincerely, Thomas G. Allan Senior Transportation Regulations Specialist Office of Hazardous Materials Standards :#

Page 21.-€ Truck Trailer Manufacturers Association HM Kafrim 1020 PRINCESS STREET ALEXANDRIA, VA. 22314 RICHARD P. BOWLING PRESIDENT FAX: 1-703-549-3014 (703) 549-3010 June 15, 1995 Edward T. Mazzullo Director, Office of Hazardous Materials Standards Research & Special Programs Administration U.S. Department of Transportation Washington, D.C. 20590 400 Seventh Street, S.W. Subject: 120% of Specified Ultimate Tensile Strength, as it Request for an Interpretation of 178.345-3(a) (2), Applies to 178.345-3(b), Static Stress Calculations Dear Mr. Mazzullo: allowable 178.345-3(a) states that the calculated design stress may not exceed the stress prescribed in the ASME Code or 25 percent of the tensile the actual tensile strength of the material used is greater than that Strength of the material used. 178.345-3(a) (2) states that if 25 percent of the actual tensile strength or 120 percent of the allowable tensile strength in prescribed in the ASME Code or ASTM standard, then either 25 percent of the ASME Code or ASTM standard may be used, whichever is less. The actual tensile strength shall be determined by physical property tests of the material used. Please confirm that in the calculation of the static stresses of a non-ASME DOT 406, DOT 407, or DOT 412 cargo tank in accordance with 178.345-3(b), that 178.345-3(a) (2) is applicable. some cases an allowable tensile strength up to 120 percent of that specified in This would mean that in either the ASME Code or the ASTM standard may be used in the static design of the ASME Code. and construction of a cargo tank in accordance with Section VIII, Division 1 Sincerely, DialoW. Viewines Donald W. Vierimaa DWV/mm Vice President-Engineering cc: Tank Conference Engineering Committee#