INNOVATION January-February 2018

F E A T U R E

D ominika Z arzycka /S hutterstock . com

Close-up of damage to the exterior of the building. Materials used for the building’s exterior cladding are thought to have been a major contributor to the rapid spread of the fire.

THE RAINSCREEN CAVITY AND THE CHIMNEY EFFECT In addition to not having sprinklers and using inappropriate material on the outside of the building, the Grenfell Tower cladding also appears to have been installed in such a way that the rainscreen—the gap left between the cladding and the interior insulation of the building where water and moisture can escape—acted as a convenient path for the fire to travel along, like a chimney. “In Canada, the code is worded such that you’re not allowed to do that,” says Lawton, “You have to have one of two protections to minimize the transfer of flame up such cavities. One option is to have fire stops, basically a sheet of metal, at every floor. The other option is to minimize the gap between the cladding and the insulation to no more than an inch to restrict the flame.”

“OUT OF ADVERSITY COMES OPPORTUNITY” Learning from the mistakes and the decisions that caused the Grenfell Tower fire is of little comfort to the family, friends, witnesses, and first responders directly affected by the tragedy. But, by looking closely at the codes and regulations in place, engineers, builders, architects, and suppliers can help ensure that a similar disaster is not repeated. Alternatives to plastic insulation material, a known fire hazard, are being pursued as demand for passive buildings in need of robust insulation grows. “There’s a market need to develop better performing insulating materials that also perform well in a fire,” says Steer. For example, spray- applied foam plastic is in common use to insulate walls but is highly combustible and requires measures to protect from fire. The alternative is mineral fibre insulation, a non- combustible material, but does not

insulate as well and requires thicker walls. In Canada, a desire to construct safer and more energy efficient buildings is also driving research into new products. The BC government’s Wood First Initiative sees BC-based researchers and design professionals exploring innovative ways to use wood for taller buildings. Wood presents unique challenges, said Steer, particularly for fire protection engineers and building code consultants, but progress is being made. For a fire as severe as the one that took so many lives at the Grenfell Tower in London in 2017 to occur, a lengthy list of fire safety precautions and building regulations appear to have been ignored and overlooked. Canada’s NBC outlines numerous construction requirements to prevent a similar catastrophe occurring. “We have layers and layers of code that will prevent something like this happening,” says Lawton, “If you follow the code.” j

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