Interpretation ID: 7196
Manager, Design Administration Dept.
Technical Division Ichikoh Industries, Inc.
80 Itado, Isehara-City
Kanagawa, 259-11 Japan
Dear Mr. Miyoshi:
This responds to your letter of April 6, 1992, asking for an interpretation of Standard No. 108. With respect to a headlamp system consisting of two lamps, each containing two light sources, you have asked "Is it permissible to have the bulb center of the lower beam lower than that of the upper beam (maximum height difference is 10mm) if they are arranged horizontally?"
Paragraph S7.5(d)(2) specifies the manner in which "the lower and upper beams of a headlamp system consisting of two lamps, each containing either one or two light sources, shall be provided . . ." In such headlamps where each light source provides a beam, the lower beam is provided "by the outboard light source (or upper one if arranged vertically)," and the upper beam is provided "by the inboard light source (or the lower one if arranged vertically)."
Although the standard could be presumed to contemplate that two light sources within a headlamp would be located on the same horizontal or vertical plane, there is no specific requirement for light source placement. Because the difference in the horizontal mounting planes for bulb centers in your design is only 10mm, this difference is not sufficient to conclude that the light sources are vertically arranged, thus requiring that the lower beam bulb center be the "upper" one, or on a plane that is higher. However, for your design to be permissible, the lower beam in this essentially horizontal array must be provided by the outboard light source in the headlamps as specified in S7.5(d)(2).
Sincerely,
Paul Jackson Rice Chief Counsel
ref:108 d:5/8/92