As news conferences go, PPG Industries Inc.'s event at SAE International's 2008 World Congress wasn't exactly typical.
Just after General Motors Corp. executives announced the company would use Saflex laminated glass in its large passenger vans to improve safety, Pete Dishart, PPG global product marketing manager showed just what can happen with a standard window made with tempered glass. With one swift move, he smashed a window on the GM van at PPG's booth April 14.
Then Dishart held out two baseball bats, and invited the media to take a whack. Three reporters later, the windows, produced under the Saflex brand name in a cooperative venture between Pittsburg-based PPG and St. Louis-based Solutia Inc., had been dinged, but had not broken.
``What people don't realize is how easily tempered glass breaks,'' Dishart said.
Laminated glass, which uses a layer of polyvinyl butyral between two sheets of glass, has found application in front windshields for more than 60 years because it does not shatter on impact. Detroit-based GM is relying on that fact to help protect rear passengers in its medium-duty full-size vans, which carry 12-15 passengers. When GM redesigned the van, it wanted to make sure passengers would remain inside the vehicle in a rollover.
GM developed a large side-curtain air bag that covers the first three rows in the van, but the bag won't work reliably if extended far enough to cover passengers at the rear, said Robert Mulcrone, program engineering manager. ``That's why we married the air bag with the glass,'' he said.
Glass and plastics laminated glass suppliers have been touting the benefits of using it in side and rear windows for a decade and slowly have won business because PVB-enhanced glass can improve acoustics as well as safety.
The van represents the biggest single laminated side windows on the road, using glass panels 72 inches long and 22 inches wide. GM makes about 20,000 of the largest vans annually, those carrying 15 passengers, and another 5,000 of the 12-passenger vans.