The fire performance criteria for internal wall cladding materials in the UK is set out in Building Regulations Part B (Fire Safety). Specifically, the regulations require that materials used for internal walls must meet the criteria for limited combustibility or Class 0 or Class 1 surface spread of flame.

Limited combustibility is defined as a material that does not ignite or contribute to the spread of fire when exposed to heat or flames. Class 0 and Class 1 surface spread of flame are measures of a material’s ability to resist the spread of flames across its surface.

Class 0 materials have the highest level of fire resistance and are suitable for use in all buildings. Class 1 materials are suitable for use in buildings other than those with sleeping accommodation, such as offices and shops.

In addition to these specific criteria, the regulations also require that internal wall cladding materials undergo testing in accordance with relevant British Standards, such as BS 476 Parts 6 and 7 or BS EN 13501-1, to determine their fire performance characteristics.

It’s important to note that compliance with these regulations is essential for ensuring the safety of building occupants in the event of a fire. It’s always best to consult with a qualified professional, such as an architect or building surveyor, to ensure that any internal wall cladding materials you plan to use meet the relevant fire performance criteria and testing standards.