Grenfell expert panel calls for more testing

The expert panel on safety set up by the government in the wake of the Grenfell Tower fire has called for a new round of tests on Aluminium Composite Material (ACM) panels of the type used in the Kensington block.

Proposals include building and setting fire to a 9m-high demonstration wall to help identify potentially dangerous materials fitted in UK tower blocks.

The Department for Local Government & Communities (DCLG) said the next phase of large scale tests would help establish how different types of ACM panels, in combination with different types of insulation, behaved in a fire. The new data would help landlords make better assessments of their properties, the department said.

Every one of the more than 180 out of 600 samples of materials removed from the exterior of a selection of UK tower blocks following last month’s Grenfell fire and tested for combustibility has failed.

The DCLG said results of the next round of tests, which will again be undertaken by the BRE, “will help landlords make decisions on any further measures that may need to be put in place to make their buildings safe following the Grenfell Tower fire”.

Meanwhile, experts have questioned whether the tests already being carried out by the BRE to establish the flammability of external cladding on local authority tower blocks serve any useful purpose. The BRE said the tests were in line with building regulations guidance.

The DCLG said the new tests would look at three different types of ACM cladding combined with different types of insulation, and would be done so in accordance with British Standard 8414, in line with the panel’s advice.

The new tests will see a 9m-high demonstration wall built, complete with cladding system – including panels and insulation – and then set on fire to replicate a severe blaze in a flat breaking out of a window and whether it then spreads up the outside wall, a scenario seen at Grenfell.

The expert panel has concluded that six combinations of cladding systems should be subjected to the BS8414 test procedure. These will incorporate each of the three common types of aluminium composite material panels, with core filler materials of unmodified polyethylene, fire retardant polyethylene, and non-combustible mineral. The two insulation materials used in the testing will be rigid polyisocyanurate foam or non-combustible mineral wool.

The panel has also called for further practical advice to be issued to landlords so that they can identify wall materials, including insulation, more easily. The government said this information would be published “shortly”.