Thirteen tall buildings have become the first to “pass” government tests, but a leading engineering expert has warned against losing sight of wider building regulation issues.
Following the fire at Grenfell Tower on 14 June, the government initiated a fire safety testing programme led by the Building Research Establishment (BRE). It has tested hundreds of aluminium composite material (ACM) cladding samples and three large-scale cladding combinations for compliance with fire safety guidance set out in the Building Regulations 2010.
A fourth large-scale cladding system test has become the first to return results which comply with building regulations. The latest test results show that a combination of ACM cladding with a fire resistant polyethylene filler – category 2 in screening tests – and a stone wool insulation has passed the test. There are 13 buildings over 18m tall in England with this cladding system.
Since the testing programme started, 269 ACM cladding samples have failed, as have all three previous large-scale cladding combinations. An independent review of current building regulations and fire safety in tall buildings is to be carried out as a result, led by EFF chair Dame Judith Hackitt.
Specialist Engineering Contractor Group chief executive Rudi Klein told New Civil Engineer that although the results were positive, better fire safety regulation and enforcement must still be brought in to avoid future disasters.
“Obviously it’s encouraging that these tests have found that there is compliance,” he said, cautioning that regulations only specify outcomes and not what materials must be used in buildings.
“What the government now needs to do is to consider a national enforcement agency that will actually ensure that we have proactive enforcement [of regulations].”
Large-scale cladding combinations are being tested for compliance with building regulations under the second route for compliance. This test follows criteria set out in British Standard 8414-1, and the results are checked for compliance with BR135. During the test a 9m high cladding system is built and then burnt to test how fire spreads across the surface.
To comply with BR135, a cladding system must not burn above a certain temperature for longer than 30 seconds within 15 minutes of the test starting. If a test is terminated early, it cannot be assessed against BR135 and therefore does not comply with building regulations guidance. In this case, the cladding combination test did not need to be stopped early. It was found compliant with criteria in BR135, and so meets building regulations guidance.
The government’s expert safety panel, led by BRE chief executive Peter Bonfield, stressed that cladding and insulation material varies between manufacturers with different calorific values, and outcomes can be influenced by how a system is fitted together.