Interpretation ID: 86-2.7

TYPE: INTERPRETATION-NHTSA

DATE: 03/17/86

FROM: STEPHEN T. WAIMEY; DEAN HANSELL -- LAW OFFICE OF DONOVAN LEISURE

TO: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TITLE: FMVSS 103 AND 104

ATTACHMT: ATTACHED TO LETTER DATED 12/29/86, TO STEPHEN J WAIMEY FROM ERIKA Z JONES, REDBOOK A29 (4) STANDARD 103 AND 104

TEXT: Dear Ms. Jones:

We write on behalf of Porsche to verify our understanding of a portion of FMVSS 103 (Windshield Defrosting and Defogging Systems) and 104 (Windshield Wiping and Washing Systems). Our question concerns the method of determining the areas to be included in calculating the percentages required to be wiped or defrosted under FMVSS 103 and 104.

Porsche is considering a windshield design that would be 5% smaller than the "A" area, as defined by the angles set forth in SAE J903c (Passenger Car Windshield Wiper Systems) and SAE J902b (Passenger Car Windshield Defrosting Systems). Our understanding is that, for the purpose of determining compliance with the percentages of the "A" area required to be wiped or defrosted under FMVSS 103 and 104, the percentages are based on the actual windshield size (less a one inch border) rather than the theoretical size that is derived from an abstract application of the specified angles in the SAE procedures.

Our conclusion is based on statements contained in SAE J903c, which is incorporated into FMVSS 104, S4.1.2, and SAE J902b, which is incorporated in FMVSS 103, S4.2. Both SAE J903c and J902b provide that "the areas used in determining the percentage of [wiped or defrosted] area are

those areas on the exterior glazing surface which are not within 1 (one) inch of the edge of the daylight opening." Thus, it is only the area that falls on the windshield itself, and excluding a one inch border at the outer edge of the exterior glazing surface, that need be used in calculating the appropriate percentages.

If our interpretation is correct, then any part of Area A (as determined by the given angles) that falls outside the windshield's physical area is immaterial.

A prompt response would be appreciated. Many thanks.

Yours truly,