Understanding Fire Protection Terms – Combustibility

Date Published

21 September 2022

Document Type





There are four recognised stages in the development of any fire: Ignition, Spread and Growth, Flash point into a fully developed fire and Eventual Decay. During the early stages, when a fire is still becoming established, the important factors are: Ignitability, Spread of Flame, Smoke Production and Flaming droplets.

Key Information

For a material to be classed as either Non-combustible or of Limited Combustibility it must achieve Euroclass A1 or A2 in reaction to fire testing. Any material rated Class B or lower is therefore classed as Combustible, albeit to varying degrees.

Whilst it is not possible to enhance any organic materials to a Class A rating, flame retardant treated wood-based materials enhance safety, add value and are fit for purpose for many applications.

Case studies

The building is the UK sales and marketing office of The VELUX Company, the Danish manufacturer of windows and roof-lights. According to the client’s brief, the design was to be ‘a practical demonstration of VELUX products in an inspirational setting’.

The Stonebridge Hillside Hub is a key scheme in the continuing regeneration of the Stonebridge Estate in West London.