Interpretation ID: aiam2224
Industry Technical Specialist
Laminated Glass
Monsanto Polymers and Petrochemicals Co.
190 Grochmal Avenue
Indian Orchard
MA 01051;
Dear Mr. Lacey: This is in response to your letter of December 22, 1975, to Mr. Gu Hunter of my staff, concerning our reasons for prohibiting the use of tempered glass in windshields of motor vehicles.; The use of tempered glass in windshields is prohibited for th following reasons:; >>>1. Tempered glass has little, if any, energy absorbing capabilit while laminated glass has intrinsic deflective characteristics that provide such capability.; 2. When tempered glass breaks, it usually either 'crazes' or shatter into many small pieces. If crazing occurs, the driver's vision becomes obscured thus not only endangering himself but others as well. If the glass shatters, the driver and other vehicle occupants are showered with glass pellets which could not only result in loss of control of the vehicle but is also likely to cause eye injuries.; 3. When cracked, tempered glass has essentially no retentiv capability, thus the likelihood of occupant ejection through the windshield opening is greatly increased in crash situations. Laminated glass, on the other hand, possesses significant retentive capability even after initial cracking of the glass laminate on either side of the plastic interlayer.<<<; If I can be of further help, do not hesitate to contact me. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs;