Interpretation ID: 2041o
International Automotive Design
I.A.D. House
Dominion Way
Worthing, Sussex BN14 8LU England
Dear Mr. Bailey:
This responds to your letter of June 10, 1988, in which you asked for an interpretation of Standard No. 104, Windshield Wiping and Washing Systems (49 CFR 571.104). More specifically, you asked two questions about the requirements set forth in section S4.1.2, Wiped area, of Standard No. 104.
You first asked whether section S4.1.2 of Standard No. 104 applies only to passenger cars. The answer to this question is yes. Section S4.1.2 reads as follows: "When tested in accordance with SAE Recommended Practice J903a, May 1966, each passenger car windshield shall ..." (emphasis added). The underlined language explicitly limits the requirements to passenger car windshields. Hence, the windshields on other vehicle types are not subject to the requirements of S4.1.2.
Your second question involved the dimensions of "Area A" used to determine whether a car complies with the wiped area requirements in section S4.1.2. Section S4.1.2.1 of Standard No. 104 specifies that the dimensions for "Area A" are established as shown in SAE Recommended Practice J903a, May 1966, and specifies that at least 80 percent of "Area A" must be wiped. Following the procedures set forth in the SAE Recommended Practice, you noted that "Area A" on a hypothetical vehicle would extend to the daylight opening area on one side of the windshield and extend beyond the daylight opening area on the other side of the windshield. When calculating the percentage of Area A that is wiped, your letter sets forth four different possible dimensions for Area A and asks which is used to determine whether the vehicle wipes at least 80 percent of Area A. Again section S4.1.2 explicitly answers this question. That section specifies that each passenger car windshield shall wipe 80 percent of Area A that "is within the area bounded by a perimeter line on the glazing surface 1 inch from the daylight opening."
Please let me know if you have any further questions or need any additional information.
Sincerely,
Erika Z. Jones Chief Counsel
/ref:104 d:ll/3/88