Following the Grenfell Tower fire tragedy, the UK Government commissioned a series of tests of different building façade panels, to establish which combinations of materials respected UK Buildings Regulation Guidance BR 135 (Building Research Establishment – Fire performance of external thermal insulation for walls of multistorey buildings).
Each test used a 9 m high wall with a complete cladding system (panels, insulation, cavity barriers) subjected to fire conditions comparable to a severe fire in a room spreading out of a window. The test establishes whether the cladding system allows vertical fire spread. Claddings using non-FR polyethylene (PE) core + rigid polyisocyanurate (PIR) insulation, non-FR PE core + mineral wool insulation, FR PE core + PIR insulation, FR PE core + phenolic foam insulation all failed the test, whereas FR PE + mineral wool insulation, limited combustibility filler + PIR insulation and limited combustibility filler + mineral wool insulation passed the test.
Cladding system fire test reports (1-7) at “Information relating to the fire at Grenfell Tower”, UK Government, August 2017 https://www.gov.uk/government/collections/grenfell-tower#fire-test-reports