Interpretation ID: 86-6.23

TYPE: INTERPRETATION-NHTSA

DATE: 12/29/86

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: STEPHEN T. WAIMEY -- LEBEOUF, LAMB, LEIBY AND MACRAE

TITLE: NONE

ATTACHMT: LETTER DATED 03/17/86 RE FMVSS 103 AND 104, TO ERIKA Z. JONES, FROM STEPHEN T. WAIMEY AND DEAN HANSELL OCC-0349

TEXT: Dear Mr. Waimey:

This responds to your letter regarding the method of determining the windshield areas required to be cleared under Standard No. 103, Windshield Defrosting and Defogging Systems, and Standard No. 104, Windshield Wiping and Washing Systems. I regret the delay in responding to your letter.

You state in your letter that your client, Porsche, is considering a windshield design that would be five percent smaller than the area of the windshield or glazing surface established as Area "A" in Standard No. 104. Area "A" is the largest of the three windshield areas, designated in that standard as areas "A," "B," and "C." Each of these areas is required to have a certain percentage defrosted within a specified time period under Standard No. 103. Similarly, each of these areas is required to have a certain percentage wiped under Standard No. 104. These areas are established by the angles which are set forth in the SAE Recommended Practices and referenced in Standards Nos. 103 and 104. Paragraph S4.1.2 of Standard No. 104 states that the percentage of each area required to be cleared must also be within the area bounded by a perimeter line on the glazing surface one inch from the edge of the daylight opening.

You also say in your letter that you understand that the percentages of the "A" area of the windshield, which are required to be cleared under these standards, are based on actual windshield size, less a one-inch border, rather than the theoretical windshield size that is derived using the specified angles in the referenced SAE procedures. You conclude that only the portion of Area "A," for example, which falls on an actual windshield, less a one-inch border, need be used in calculating the percentageswhich are required to be cleared under these standards.conclude that any portion of Area A which falls outside a windshield's actual size is immaterial with regard to the areas required to be cleared under these standards.

2

The agency believes your interpretation of Area "A" is correct, for the following reasons. Unlike the Federal Motor Vehicle Safety Standard No. 128, Fields of Direct View, which was issued and rescinded in 1981, Standards Nos. 103 and 104 were not intended to regulate the size of structural and other obstructions in the driver's field of direct view. Paragraph S4.2 of Standard No. 103 requires each passenger car windshield defrosting and defogging system to meet the requirements of section 3 of SAE J902, when tested in accordance with paragraph S4.3 of the standard, except that the "entire windshield" specified in SAE Recommended Practice J902 must be that established as Area A in accordance with Standard No. 104.

Thus, Area A is defined according to the requirements of Standard No. 104. Paragraph S4.1.2.1 of Standard No. 104 states that Area A of a passenger car windshield must be established as shown in Figures 1 and 2 of SAE Recommended Practice J903a, May 1966, using the angles specified in Columns 3 through 6 of Table I, II, III, or IV, as applicable. These tables are set forth in Standard No. 104 and apply to passenger cars of specified overall widths, i.e., from less than 60 inches to 68 or more inches. The angles in these tables vary according to the overall width of the passenger car model. This office agrees that the projection of the correct angles onto an actual windshield surface may produce a projected surface larger than the windshield itself and that only the portion of Area A which is projected onto the actual windshield is material.

Paragraph S4.1.2 of Standard No. 104 also limits the percentage of the windshield required to be cleared to that inside the perimeter line on the windshield one inch from the edge of the daylight opening. Since Standard No. 103 references Standard No. 104 for the determination of Area A, this office also agrees that the percentages of the windshield required to be cleared under Standard No. 103 are those inside the perimeter line on the windshield one inch from the edge of the daylight opening.

As an aside, we note that you state in your letter that your conclusion is based on statements contained in SAE Recommended Practices J903c and SAE J902b. Paragraph S4.2 of Standard No. 103, Windshield Defrosting and Defogging Systems, references SAE Recommended Practice J902, Passenger Car Windshield Defrosting Systems, August 1964, not SAE Recommended Practice J902b, as stated in your letter. Paragraph S4.1.2 of Standard No. 104, Windshield Wiping and Washing Systems, references SAE Recommended Practice 903a, May 1966, not SAE J903c, as stated in your letter. In any case, we do not believe the quoted statements affect the requirements of either Standard No. 103 or Standard No. 104, because each reference in the safety standards to an SAE Recommended Practice is to a specific portion of it, not to general language such as your quotation.

I hope this information is helpful to you.

Sincerely,