DATES: Comments must be received on or before July 5, 2016
SUMMARY AND EXCERPTS: NHTSA is proposing to issue an FMVSS No. 217a to specify an impactor test of glazing material used in side and rear windows. In the tests, a 57 lb impactor would be propelled from inside a test vehicle toward the window glazing at 13.4 mph. Each window must comply with the performance requirements below for the following three impacts in a NHTSA compliance test: (a) An impact near a latching mechanism of an intact window; (b) an impact at the center of the daylight opening of an intact window; and (c) an impact at the center of the daylight opening of a pre-broken window. The impactor and impact speed in these proposed tests simulate the loading from an average size adult male impacting a window on the opposite side of a large bus in a rollover.
The proposed performance requirements are as follows:
- In tests described in (a) and (b) in the above paragraph, the window would have to prevent passage of a 4 inch diameter sphere during the impact, and after the test. The agency would assess the window during the impact by determining whether any part of the window passes a defined reference plane. NHTSA believes these requirements would ensure that glazing is securely bonded to window frames, no potential ejection portals are created due to breaking of glass, and windows remain closed when impacted.
- In the test of (c) above, the maximum displacement of the impactor at the center of the daylight opening would be limited to 6.9 inches for pre-broken glazing. This requirement in particular would drive the installation of advanced glazing.
In addition:
- Emergency exit latch protrusions may not extend more than one inch into the emergency exit opening of the window when the window is opened to the minimum emergency egress opening. NHTSA believes this requirement would minimize the potential for the latch plate protrusions to hinder the emergency egress of passengers.
- Latches would have to remain functional following the impact test to ensure that occupants can open the emergency exits to egress the vehicle after a crash.
NHTSA believes the proposed requirements would fill a gap currently existing in NHTSA’s motor coach and large bus safety regulations and that advanced glazing in window openings and improved mountings would mitigate the risk of ejection of occupants who may not be restrained at the time of the crash, and the risk of partial ejections of both restrained and unrestrained occupants.
