Grenfell: Metal-polyethylene cladding 'principle reason' for fire spread

London, UK – The aluminium composite material (ACM) rain screen was the 'principle reason' why flames rose up the side of the Grenfell Tower. The panels had a flammable polyethylene core, which acted as a source of fuel.

This is one of the key findings in the leaked first stage report from the Grenfell inquiry, and published by the UK's Daily Telegraph newspaper. In the months leading up to the fire, the tower's external walls were refurbished, and an ACM crown was added to the building. That work did not meet building regulations.

Martin Moore-Bick, the inquiry's chairman, added that there is 'compelling evidence' that the walls did not 'adequately resist the spread of fire'. The report adds that the fire's spread was accelerated by insulation boards and window surrounds, both of which had combustible materials. 

Video evidence suggested the crown was 'primarily responsible' for the spread of the fire horizontally. Flames had only spread vertically before they reached the crown, the report says.

The fire started in a Whirlpool fridge-freezer, and escaped the flat by burning through a uPVC window frame into the space between the insulation and the rain screen.

Since the disaster, survivors and bereaved families have maintained that the building work did not meet UK building regulations. 

The findings also reflect the position of the UK's building inspectors organisation, Local Authority Building Control. In 2014, the group issued a certificate allowing the use of PIR insulation panels and fibre-cement panels. 

Fire service procedures are also criticised in the leaked report. It is believed to state that the fire commanders did not realise the fire-proof compartments had failed, so they did not try to evacuate the tower. 

Grenfell Tower is in the Royal Borough of Kensington and Chelsea, a west London borough. In addition to the public inquiry, London’s Metropolitan Police is conducting a criminal investigation into the events of the night. This could last for years, and that it is the largest ever carried out in the UK. 

The report's official publication on 30 November will mark the end of the first phase of the enquiry. The second phase will start in early 2020. This is link to a list of the topics it will cover.