# Truck Trailer Manufacturers Association — Hazardous Materials Safety Interpretation

**Citation:** 98-0595  
**Type / status:** guidance / guidance  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 1998-05-05

98-0595 response to Truck Trailer Manufacturers Association concerning 178.345.

## Document text

<<<PAGE 1>>>

U.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 2>>>

1.-€
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

## Provenance

- Official: Yes
- Source: <https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/1998/980595.pdf>
- Source ID: `phmsa`
- SHA-256: `56a76ed1d72d4fa8958bdb77a8398e456f90c7f461f5f729ca2227210568b897`
- Retrieved: 2026-08-20T00:59:31.977Z
- Exported: 2026-08-22T13:56:48.236Z
- Document slug: `phmsa-interpretation-98-0595`

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