Manager, Safety Standards
Safety Affairs & Regulations
General Motors Corporation
1660 L Street, N.W.
Washington, DC 20036
Dear Mr. Laux:
This responds to your letter to me in which you ask whether the back door glazing on two models of General Motors vehicles would be excluded from the definition of "back door" in the September 28, 1995 amendments to Federal motor vehicle safety standard (FMVSS) No. 206, Door locks and door retention components. The answer is yes as to the glazing half of both door designs.
The agency published a final rule on September 28, 1995, (60 FR 50124) extending the requirements of FMVSS No. 206 to the back doors of passenger cars and multipurpose passenger vehicles (MPV), if so equipped, with a gross vehicle weight rating of 4,536 kilograms (10,000 pounds) or less. Exclusions from the definition of "back door," however, include:
[A] door or window composed entirely of glazing material whose latches and/or hinges are attached directly onto the glazing material (emphasis added).
Your questions address the meaning of the emphasized words as applied to the two MPV models in question.
Both MPV models you refer to are equipped with 2-part back doors. The top halves of the doors are composed of glazing that swings outward and upward. The bottom halves are all-metal tailgates that swing outward and downward. On one model the hinges are attached to the glazing by use of mechanical fasteners that are separated from actual contact with the glazing by a washer. The upper part of the door on the other model is composed of glazing, but the hinges are imbedded in the glazing, then covered by a decorative composite material that you refer to as ARIM@ (reaction injection molding). This door is also equipped with a high- mounted stop lamp centered at the top of the door.
You ask whether both windows would be deemed composed "entirely" of glazing material when both contain electric defroster elements and as pointed out above, one contains decorative surround and a high-mounted stop lamp. You suggest that "the agency's intent is to exempt those doors or windows whose latches and/or hinges are attached to glazing material which is the principal structural component of the door or window, rather than to mandate compliance of doors and windows that are not `composed entirely of glazing material'" (emphasis in original).
In excluding doors and windows "composed entirely of glazing material," the agency was referring to the very type doors you describe, that is, where the entire door itself is glazing as opposed to window glazing that is mounted in and framed by a metal door. As explained in the preamble to the final rule, a door composed only of glazing, be it glass, plastic, or glass/plastic, could be expected to fail in a crash before the latches or hinges would fail. In that case, it would be meaningless to require the latches and hinges to comply with the standard. It is immaterial that the glazing might contain defrosting elements, decorative material, or a high-mounted stop lamp, since those components do not strengthen the glazing. Thus, as you correctly pointed out in your letter, the agency intended to exclude from the requirements of the standard those doors and windows where glazing is the "principal structural component of the door or window."
Your other concern was whether the hinges on your upper door halves were attached "directly onto" the glazing. With respect to the model on which the door half is attached by mechanical fasteners separated from the glazing by a washer, the agency would still consider those hinges attached "directly onto" the glazing. It could reasonably be expected that the bare metal of the hinge would be separated from the bare glazing of the door or window by a washer, gasket, or some other cushioning material. The same consideration would apply to the model in which the hinge is embedded into the glazing and covered with decorative material for aesthetic purposes. Either way, the hinges are mounted directly to the glazing, as opposed to being attached to the metal frame into which the glazing is mounted. Accordingly, the agency considers the upper halves of both door designs as being composed entirely of glazing, and the hinges of both are mounted directly onto the glazing. Both doors, therefore, are excluded from the requirements of the standard.
The above discussion does not apply to the bottom halves of the doors in question. Since those doors are metal doors, the latches and hinges on them must comply with the requirements of the standard.
If you have any further questions or need additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992.
Samuel J. Dubbin Chief Counsel ref:206 d:5/6/96