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August 4, 2011

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IIlicit cheating pervades glass work

ILLEGAL shortcuts amid a lack of regulation plague the exterior glass industry, leading directly to low-quality glass that may explode and rain shattered pieces of windows from skyscrapers and other buildings.

About 90 percent of exterior wall glass in Shanghai is made of cheaper tempered glass instead of safe but expensive dual-paned glass, industry insiders told the Youth Daily.

While both kinds of materials may spontaneously break, dual-pane glass is much safer because it happens less often and, even when it does, the tiny pieces are held together by a type of glue. Dual-pane glass therefore does not burst explosively and fall as thousands of small pieces, as does tempered glass.

According to an engineer surnamed Wang with a local glass-manufacturing company, tempered glass costs 40 yuan (US$6.21) to 50 yuan per square meter, while dual-pane glass usually goes for 80 yuan to 90 yuan per square meter. Wang said that means the developer of a typical 20-story building can save half a million yuan by using tempered glass.

During the bidding process, companies will virtually always purchase glass based on price alone, regardless of quality.

More ominously, there are growing numbers of glass manufacturers who have started lowering their prices by making the glass thinner and by using inferior materials, said Zhang Xian, researcher with the China Academy of Building Research.

"For instance, even when the developer is required to use 10-millimeter-thick wall glass, the suppliers offer cheaper glass only 6 millimeter thick, posing great danger of explosions," Zhang told the newspaper.

And there is a serious lack of regulation over the manufacturing and bidding process, said Zhang.

According to a regulation issued by the Ministry of Housing and Urban-Rural Development, the building owner must carry out inspections of exterior glass every 10 years to check for safety. But at many local high-rises, 10 to 15 years often go by because the owners don't know how to carry out the inspections.

"We can only send security guards to watch the glass to see if there are any cracks or signs of explosion," said an official with the property management company of the Shanghai International Finance Center.

The officials said the guards patrol the building to observe the glass with telescopes, but their inspections did not prevent a "broken glass shower" that rained down from the building's 38th floor on July 21.


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