A cladding system using stonewall insulation has become the first to pass new fire safety tests ordered by the government since the Grenfell tragedy in June.
The fourth in the government’s series of large-scale fire safety tests, that will allow experts to better understand how different types of cladding panels behave with different types of insulation in a fire, has been completed by the Building Research Establishment (BRE).
This fourth test was of a wall cladding system consisting of Aluminium Composite Material (ACM) cladding with a fire resistant polyethylene filler (category 2 in screening tests) and stone wool insulation (a form of mineral wool). This combination of materials has passed the test.
The government’s Expert Panel advise that the results show that this combination of materials can be compliant with current Building Regulations when installed and maintained properly. It could therefore offer a possible solution for some buildings with other cladding systems which have been identified as a hazard.
However the Expert Panel note that cladding and insulation materials can vary between manufacturers and can have different calorific values. The way materials have been fitted and maintained can also affect the safety of the cladding system.
Therefore the clear advice from the Expert Panel is that building owners need to continue to take professional advice as to whether any remedial work is necessary to ensure the safety of their building. The test results will help inform this work but they must also take into account the specific circumstances of their building.
13 buildings over 18 metres tall in England are known to have this combination of ACM with a fire resistant polyethylene filler (category 2) and stone wool insulation. Following initial screening tests, government issued advice to building owners detailing immediate interim safety measures that needed to be undertaken. These measures have been completed for all 13 of these buildings.
The Department for Communities and Local Government concluded “The clear advice from the Expert Panel is that building owners need to continue to take professional advice as to whether any remedial work is necessary to ensure the safety of their building.”