The non-uniformity of temper of 27 motor vehicle door windows as measured by the polarisation method is presented, illustrated by two photographs of windows between crossed polarizers. The tempered glass fracture characteristics of 11 Geo Prism door windows are illustrated by two video frames of the windows after fracturing by door deformation slowly applied at bumper level. The speed of some moderate sized fragments was measured to exceed 60 km/h, due to strain relief rather than contact by an intruding object. Glazing history is briefly summarised, with the support of the NHTSA conclusion that more than 1300 lives per year could be saved cost effectively by replacing tempered glass by an "advanced glazing". (A)
Samenvatting