Interpretation ID: nht91-1.22

DATE: January 15, 1991

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Kotaro Yakushiji -- Vice President, Emissions & Safety Technology, Mazda Research & Development of North America, Inc.

TITLE: None

ATTACHMT: Attached to letter dated 11-30-90 to Paul Jackson Rice from Kotaro Yakushiji (OCC-5508)

TEXT:

This responds to your letter of November 30, 1990 in which you request an interpretation of Standard No. 216, Roof Crush Resistance-Passenger Cars. Mazda requests an interpretation of the proper application and orientation of the test block when testing vehicles equipped with roof mounted accessories. Specifically, Mazda asks about a vehicle with a sunroof wind deflector. The deflector is constructed of plastic material and is mounted at the wind screen header. You state that, for practical purposes, the wind deflector is not removable during use but can be removed for testing. You further state that the wind deflector neither contributes to nor detracts from roof strength.

You believe that there are three possible test conditions. The first condition would conduct the test with the wind deflector in place. The second condition would conduct the test with the wind deflector removed and with the contact point greater than ten inches from the forward most point of the longitudinal centerline. The third condition would conduct the test with the wind deflector removed and with the contact point positioned according to section S6.2(d) of Standard No. 216.

We have concluded that it is appropriate to conduct the roof crush test with the wind deflector removed. We have reached this conclusion because the purpose of the test is to measure the strength of the roof, not the strength of roof mounted accessories. Further, conducting the test with the wind deflector in place could influence the positioning of the test device.

We have concluded that the third condition, rather than the second condition, is appropriate because the contact point in the third condition is positioned according to section S6.2(d) of the standard. As we stated in a prior interpretation letter (letter of October 3, 1980 to William Blythe), the agency intends to adhere to the ten inch dimension specified in section S6.2(d) regardless of roof configuration.

I hope that this has been helpful. If you have any further questions, please contact John Rigby of this office at 202-366-2992.