Interpretation ID: nht90-3.59

TYPE: Interpretation-NHTSA

DATE: August 16, 1990

FROM: Edward R. Heussner -- Consultant, Comp U Tence

TO: Paul Jackson Rice -- Chief Counsel, NHTSA

TITLE: Re Interpretation of Requirements for FMVSS 219 - Windshield Intrusion Zone

ATTACHMT: Attached to letter dated 1-4-91 to Edward R. Heussner from Paul Jackson Rice (A37; Std. 219; VSA 108(b)(2)

TEXT:

I am working on the compliance documentation for an automobile manufacturer.

In the process of studying the data, charts and films of the impact tests I noted the windshield wiper would pass thru the "protected zone" on some tests. I called your office on Friday August 10 and talked with Dorthy Nakama. My initial question of he r was is the windshield wiper considered to be a component . . . "normally in contact with the windshield" . . . as per the standard. She assured me that the wiper fits that definition and thus is not a problem.

We then discussed the next phrase regarding "penetration." The standard states that in the area immediately below the protected zone ... no such part of the vehicle shall penetrate the inner surface of that portion of the windshield, within the DLO, bel ow the protected zone.

My question revolves around what constitutes penetration? Specifically does penetration occur when the windshield is deformed in the region . . . or does some vehicle component have to actually protrude thru and puncture the "glass-plastic" in the area in question? I used the analogy of a bowling ball being dropped on a windshield. The dimple so created would certainly protrude inward yet I would not have considered it to have penetrated. Thus, in order for penetration to have occurred does some veh icle component have to go thru the windshield or is "obscuring" of the glass sufficient to demonstrate failure in this instance?

I have one other question regarding the test procedure for FMVSS 219. The standard defines a protected zone, degree of penetration and method of measurement. It is my understanding that many organizations test vehicles for several standards simultaneou sly (i.e. 208, 212, 219 & 301) and consequently considerable data is lost when the protected zone styrofoam template is glued to the windshield. Thus it is quite common to use the results of this multi-standard test to prove compliance to 219 under a NH TSA approved deviation to the stated approach.

Is engineering judgement acceptable to the agency in this instance. That is to say that analysis of the films could easily show nothing came near the protected zone. However, if some vehicle component did in fact "approach" the zone would another test, just for 219, be required.

Film analysis is quite advanced today, but tracing the path of an object to within 1/4" of an "imaginary surface" is probably expecting too much. Your comments on this issue would be welcome. If in fact the practice is to not

use the styrofoam template, perhaps the standard should be revised to reflect this. The alternative is very costly. Full vehicle barrier tests cost in excess of $100,000. At a nominal $1000 profit per sale, this translates into 100 sales just for that test. I would suspect that $100,000 plus dollars could be better spent towards a safer vehicle.

Thank you for your consideration of these questions, your prompt reply would be greatly appreciated. Keep smiling and have a super day.