Metal composite material

On 1 June 2022, the government introduced a ban on the use of metal composite material (MCM) panels with unmodified polyethylene (PE) core on all new buildings at any height. This is the type of cladding that was used on Grenfell Tower.

Research published by the Department in April 2020 demonstrated that this type of MCM PE poses such a significant fire risk that an outright ban on its use on any buildings, regardless of height or purpose, is justified.

The cladding used on Grenfell Tower was actually aluminium composite material (ACM) with an unmodified polyethylene core (ACM PE, or ACM category 3). MCM PE includes any metal, alloy or metal compound.

Metal composite materials are defined in approved document B of the building regulations as: '...any panel or sheet, having a thickness of no more than 10mm which is composed of a number of layers two or more of which are made of metal, alloy or metal compound and one or more of which is a substantial layer made of a material having a gross calorific value of more than 35MJ/kg when tested in accordance with BS EN ISO 1716. A substantial layer is defined as a layer which is at least 1mm thick or has a mass per unit area of at least 1kg/m².'

For more information see: Metal composite material panel systems MCM and MCP and ACM cladding.

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