TEMPORARY STRUCTURES experts were this week asking whether an inflatable sculpture that broke free of its guy ropes in County Durham, on Sunday had been properly engineered.
Two women died and 13 more people were injured when the 50m x 50m, 5m tall inflatable Dreamspace sculpture was lifted up 40m by a gust of wind.
The sculpture was created in 1996 by artist Maurice Agis.
Its 113 interlinking octagonal cells were fabricated from lightweight PVC. It was inflated using air pumps Members of the public were able to enter the sculpture through a single vertical slit in the skin to explore its colour saturated interior.
The structure was tethered around its exterior to the ground via ropes that appear to have been looped through the apertures between the interconnecting rings of the cells (see diagram). The guy ropes were secured to steel pegs approximately 450mm long.
But it was unclear this week what, if any, codes the structure had been designed to.
The Health & Safety Executive is investigating the catastrophe with the police.
Chester-le-Street District Council gave permission for the sculpture to be erected in the town's Riverside Park.
Neither body could say whether any information existed on the sculpture's structural performance.
But Performance Textiles Association (PTA) secretary Michael Skelding said that the sculpture fell outside any obvious set of guidelines.
The PTA represents manufacturers of fabric structures including bouncy castles and marquees.
'There's no one code to which the creator of this structure could have looked. They would have to have looked around, and mixed and matched, ' said Skelding.
anding Committee on Structural Safety secretary John Carpenter said that there has been a trend towards creating ever larger structures in the entertainment industry, which is raising some serious safety concerns.
'When you scale things up you have to make sure you are extrapolating all the effects. If you increase the size of something subject to wind load by a factor of two, say, it doesn't follow that you'll need only twice as many anchors. You may need far more.' The Dreamspace sculpture is the latest and largest in a series of inatable, multi-cellular structures created by Agis over two decades.
Evolution of the concept has seen it grow from 3m high to 5m, and from approximately 10m x 10m in plan to 50m x 50m.
'Something 5m high is as tall as a house, ' commented Carpenter. 'It's going to be subject to signicant windage.' The HSE is investigating under the terms of the Health & Safety at Work Act (1974).
Agis was unavailable for comment.