Interpretation ID: aiam3840
Executive Engineer
Vehicle Regulations
Volkswagen of America
Inc.
P.O. Box 3951
Troy
MI 48007-3951;
Dear Mr. Haenchen: This is in reply to your letter of April 25, 1984, asking two question with respect to the humidity test for replaceable bulb headlamps specified in Motor Vehicle Safety Standard No. 108.; With reference to paragraph S6.8, you mention the relative humidit figure of 90 *+* 10 percent, and your interpretation that the six-hour cycle of the test should be run at 90 percent and that the 10 percent tolerance 'is intended to cover any drift in the instrumentation, controls and the process of generating this humidity.' We concur that this is a reasonable interpretation of this requirement.; You have also asked when the headlamp must be inspected after th humidity test, as paragraph S4.1.1.36(d)(7) is silent on this point. It is your interpretation that this inspection must occur directly following the test, and before the photometrics of the lamp are measured, even though, in your view, it would be more convenient to check it after the photometric test. Your interpretation is correct, this inspection must occur within the 9 to 11 minutes specified for beginning the photometric test after completion of the humidity test.; Sincerely, Frank Berndt, Chief Counsel