In the wake of the Grenfell Tower blaze in June, that killed at least 80 residents, the Building Research Establishment has been testing various cladding systems. In the first three rounds of testing aluminium composite material (ACM) cladding, all three systems that were tested failed. The 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 passed the test.
There are 13 buildings over 18 metres tall in England that are known to have this combination of ACM with a fire resistant polyethylene filler (category 2) and stone wool insulation.
In a carefully worded statement, the government said that its Expert Panel advises 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.”
It added: “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.”
For the full report of the fourth test,see Fire test report: DCLG BS 8414 test no.4