The cause of the fire, which has left at least 30 people dead, is yet to be determined, but the building’s cladding is being blamed for the inferno’s rapid spread.
The public housing block’s cladding had been changed in a 2016 renovation, but reports have emerged that contractors installed a cheaper, less flame-resistant material. The Guardian reported that they used aluminum composite cladding on the building’s exterior, but opted to use a plastic type called Reynobond PE, rather than Reynobond FR, which stands for fire-resistant.
Using the fire-resistant version would have cost a few dollars more per square metre, according to the newspaper.
The cladding has caused fires to spread quickly in the past. A 63-storey luxury hotel in Dubai with problematic cladding went up in flames on New Year’s Eve 2015, injuring a handful of people. A blaze at a building in Melbourne, Australia, in 2014 was later directly linked to the type of combustible cladding in place on the structure and triggered an audit of many of the city’s high-rises.
The International Building Code calls for structures taller than 12 metres to use fire-resistant material.
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Canadian regulations clearly spell out rules for cladding that can be used on buildings four storeys or higher in height. They state that the material needs a fire rating of at least one to two hours — a window that would theoretically allow most people ample time to escape a blaze.
All exterior cladding materials for buildings higher than four storeys must be tested for fire resistance and comply with strict standards. The Canadian Commission on Building and Fire Codes, part of the National Research Council, updated its regulations as recently as 2015.
Provinces often have their own set of regulations.
The Ontario Building Code, for example, prohibits the use of “combustible cladding” on buildings higher than six storeys.
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“These requirements have been in place since 1990 and apply whether a building is residential or another use,” the Ontario Office of the Fire Marshal told Global News.
Shamim A. Sheikh, a civil engineering professor at the University of Toronto, says the Canadian Standards Association (CSA) provides fire safety grades for materials that are “reasonably uniform” across Canada.
“Fire safety code at the CSA level will usually be adopted by various jurisdictions, including provinces and cities,” he said.
Sheikh added that companies selling materials will also typically ensure their products meet these standards.
Reynobond, the U.S. company that supplied materials for the Grenfell Tower renovations, also sells products in North America. However, it warns on its website that use of Reynobond PE is discouraged by the International Building Code, and in several countries, for taller structures.
-With files from The Canadian Press and The Associated Press