Probably the most significant factor in the Grenfell Tower fire tragedy is the failure to specify non-combustible cladding and insulation on building exteriors. How could so many towers be clad in materials that were combustible enough to enable fire to spread in minutes?
Back in May last year, Buildingtalk highlighted the misunderstandings in the industry about the regulations on cladding and fire safety and warned about the dangers.
Tim Vincent, Head of Technical at ROCKWOOL, examined the role of non-combustible stone wool insulation in meeting the fire safety challenges of cladding and rainscreen insulation for buildings over 18m high. He said: “The straightforward route to demonstrating compliance with BR 135 and Guidance note 18 in our view is to use stone wool insulation that is non-combustible. Non-combustible products will not contribute in any stage of the fire, including a fully developed fire according to the European reaction-to-fire classification standard BS EN 13501-1.”
Since the tragic fire at Grenfell Tower, the cladding and insulation have come under close scrutiny. Combustible material on the exterior of the building is implicated in the rapid and fatal spread of the fire and concern about this material has led to urgent tests on all other similar tower blocks.
To date, 60 high-rise buildings in 25 local authorities in England have failed fire safety tests. Every cladding sample collected so far from high-rises in 25 local authority areas has failed tests for combustibility (see BRE report on Buildingtalk).
It seems that the regulations in England were not specific enough and/or widespread misunderstandings within the building industry about the requirements. The comprehensive practice of fitting combustible material seems to have been permitted within the regulations and passed by building control.
However, in Scotland, where building regulations were now devolved, a change to building regulations in 2005 made it mandatory for builders to ensure that any external cladding “inhibited” fire spreading. The new regulations were introduced following a 1999 fatal fire in Garnock Court, a 14 storey tower block in Scotland. A corner of ribbon of cladding on the block caught fire and the blaze reached the 12th floor within 10 minutes.
An inquiry into the fire led to the tightening of the rules in Scotland.
The Building (Scotland) Act 2003 introduced the Building (Scotland) Regulations 2004 which came into force on 1 May 2005. The aim was that any addition to the outside of a building which had the “potential to lessen its resistance to external fire spread” should be subject to more stringent mandatory building regulations. The specific aim was that “Every building must be designed and constructed in such a way that in the event of an outbreak of fire within the building, or from an external source, the spread of fire on the external walls of the building is inhibited.”
Local authorities and registered social landlords reviewed their existing building stock and the cladding systems used and it seems that the outcome of this and regulation changes have meant that no local authority or housing association high-rises in Scotland used the type of cladding installed on Grenfell Tower.
Brian Donohoe, the MP for Central Ayrshire until 2015, said the inquiry contributed to the tightening of the rules in Scotland said that the “tragic fire in Irvine in 1999 led to a revisiting of regulations, which meant that all cladding that was used in high-rise dwellings had to be non-combustible.”
The images above compare the rapid fire spread on the outside of the Garnock Court and Grenfell Tower buildings. The similarity is striking.
However, industry and government failed to follow the prudent Scottish lead, with tragic consequencies.
We also ask about fitting sprinkler systems, one of the most effective tools available to prevent the spread of fire in tall buildings.
Regulations in England mean that only buildings constructed since 2007 and which are taller than 30m are required to have sprinklers fitted. This requirement wasn’t applied retroactively so did not apply to Grenfell Tower, which was built in 1974.
After the fire at Lakanal House in south London in 2009 that killed 6 people, and the fire at Shirley Towers, Southampton, in 2010, which killed two fire fighters, both coroners recommended that providers of housing in high-rise residential buildings containing multiple domestic premises consider the retrofitting of sprinkler systems.
However, nowhere in the UK is it a requirement to retroactively fit sprinklers in existing buildings and fewer than 1% of council tower blocks are fitted with sprinklers.
The British Automatic Fire Sprinkler Association (BAFSA), the trade body for the fire sprinkler industry, said retrofitting Grenfell Tower with sprinklers might have cost £200,000. It cost the council £1m to install sprinklers in three tower blocks after the Shirley Towers fire in 2010.
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