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Interpretation ID: 22594



    Mr. Henry E. Seiff, P.E.
    Director of Technology
    The Natural Gas Vehicle Coalition
    1100 Wilson Boulevard, Suite 850
    Arlington, VA 22209


    Dear Mr. Seiff:

    This is in response to your letter of January 3, 2001, in which you request an interpretation of the bonfire test procedures of Federal Motor Vehicle Safety Standard No. 304, "Compressed Natural Gas Fuel Container Integrity." The National Highway Traffic Safety Administration (NHTSA) recently amended these procedures, and you ask whether the new procedures specify both a horizontal and vertical test for compressed natural gas (CNG) fuel containers less than 1.65 meters in length, or only a horizontal test. The answer is the new procedures specify only a horizontal test for such containers.

    In the past, Standard No. 304 did specify that CNG fuel containers less than 1.65 meters in length were tested in both the horizontal and vertical positions. However, on October 30, 2000, NHTSA amended the standard's bonfire test procedures. (65 FR 64624).

    Now, under S8.3.2(a) of Standard No. 304, the CNG fuel container is positioned "in accordance with paragraphs (b) and (c) of S8.3.2." Paragraph (b) of S8.3.2 specifies that the CNG fuel container is positioned "so that its longitudinal axis is horizontal and its bottom is 100 mm (4 inches) above the fire source." (Emphasis added). Paragraph (c)(1) of S8.3.2 specifies that a CNG fuel container that is 1.65 meters (65 inches) in length or less is positioned "so that the center of the container is over the center of the fire source." Thus, taken together, paragraphs (b) and (c) of S8.3.2 specify that a CNG fuel container that is 1.65 meters in length or less is positioned so that its longitudinal axis is horizontal, its bottom is 100 mm above the fire source, and its center is over the center of the fire source.

    The new bonfire test procedures do not specify that a CNG fuel container that is 1.65 meters in length or less is tested in the vertical position.

    I hope you find this information useful. If you have any further questions regarding this matter, please feel free to contact Mr. Dion Casey in the Office of Chief Counsel at (202) 366-2992.

    Sincerely,

    John Womack
    Acting Chief Counsel

    ref:304
    d.2/13/01