Interpretation ID: aiam0965
Vice President
AM General Corporation
32500 Van Born Road
Wayne
MI 48184;
Dear Mr. Stewart: This is in reply to your letter of December 4, 1972, requesting certai interpretations of Motor Vehicle Safety Standard No. 217, Bus Window Retention and Release'.; You ask whether emergency-exit release' requirements (S5.3.1) can b met by an exit (a window in your case) which is merely pushed out for passenger egress, or whether the exit must be mechanically locked in place. Although you do not describe your system in detail, it does not appear to us that a window that can be pushed out' without a latch or other mechanism' can possibly satisfy the standard. S5.3.1 of the standard reads, Each push- out window or other emergency exit shall have a release mechanism or mechanisms located within the regions specified...' More importantly, however, the quantitative requirements of the standard make a release mechanism necessary. The retention requirements of S5.1 specify that the window in its normal configuration shall withstand a force of up to 1200 pounds, or until the glass itself breaks or stretches a specified amount. S5.3, in contrast, requires that the window shall be releasable by the application of forces not exceeding 60 pounds.; You ask whether the requirement of S5.1(b) is intended to reflec possible results of applying the test sphere to tempered glass. This requirement, which was clarified in the *Federal Register* of September 6, 1972 (37 F.R. 18034), applies to any bus window which is subject to S5.1. While the requirement does reflect the performance of tempered glass, it is expressed in terms of performance and its application is therefore not limited only to tempered glass.; Yours truly, Richard B. Dyson, Assistant Chief Counsel