Friday, January 05, 2007
The roof at B.C. Place stadium has collapsed.
The fabric roof fell into the empty stadium shortly after noon today.
The cause was not immediately determined, Vancouver has suffered all morning from a combination of bitter cold, strong winds and heavy sleet.
The roof is held up by air pressure, so even a tiny tear in the fabric could cause the roof to collapse. The stadium is home to the B.C. Lions football club, and its construction was completed in 1983.
B.C. Place Stadium, the world’s largest air-supported domed stadium, holds more than 60,000 seats and is covered by Teflon-coated fibreglass fabric that is 1/30 inch thick but stronger than steel.
Until today, B.C. Place was the world’s largest air-supported domed stadium covering 10 acres in all, with a circumference of 760 metres (2,500 feet), according to the stadium's website.
There are two layers of fabric with a four-foot space between them.
When it snows, like today, hot air is supposed to be pumped between these layers to melt 12 centimetres of snow per hour.
The total thickness of each layer of roofing material is only 1/30 inch (0.85 millimetres).
Electric-powered fans keep the air pressure inside the stadium at a higher level than the air outside. There are no beams in the roof -- extra air pressure is the only thing that supported the roof.
If the fans were turned off and the doors shut, it would take four to six hours to deflate the roof -- but spectators today said the roof collapsed within minutes.
As well as being home field to the B.C. Lions football team, the stadium has used for concerts, trade shows and concerts.
It has hosted Queen Elizabeth, Pope John Paul II, Prince Charles and Lady Diana and Bill Clinton.
The Rolling Stones, U2, The Three Tenors, Pink Floyd and the Beach Boys have played there.
The stadium was slated to play a prime role in the 2010 Olympic Winter Games as the venue of the opening and closing ceremonies.
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