The latest cladding system using phenolic foam board insulation with an ACM system filled with a fire retardant polyethylene material has failed the large-scale fire test.
Already 22 buildings have been reported with this type of cladding system, bringing the mininium tally of residential towers failing Building Regulations fire performance guidance to 228.
Results are now in from six of the seven planned large-scale fire tests on different combinations of cladding and insulation systems. The final test on the least combustible combination of elements is expected to pass.
Each of the three common types of aluminium cladding material panel, using either core filler materials of unmodified polyethylene (PE), fire retardant polyethylene (FR) or limited combustibility mineral (A2) are being checked.
These are being tested in combination with two insulation materials – rigid polyisocyanurate (PIR) foam or non-combustible stone wool. The seventh test, later added to the testing programme, examined the performance of commonly-used phenolic foam insulation board with ACM with a fire resistant filler (FR).
Even with the latest test information the Government still advises that building owners need to continue to take professional advice regarding remedial work that takes into account the specific circumstances of their building.
The way materials have been fitted and maintained can also affect the safety of the cladding system.
The Government said it will provide more definitive advice for building owners once it has the result the final test.
But the finding that over 200 buildings over 18m have failed fire resistence tests ask big questions about the present building regulation and enforcement systems at work in the industry.
Last month the government announced an independent review of building regulations and fire safety, focussed on the regulatory system around the design, construction and on-going management as well as related compliance and enforcement issues.