Hewins Oak
Fire performance of timber cladding

Fire performance of timber cladding

Classification at a glance

The reaction to fire performance of timber cladding is defined under EN 13501-1, and construction products are assigned a Euroclass rating under this system. The Euroclass system comprises ratings from A - F, and describes characteristics such as flame spread, ignitability, heat release, smoke production, burning droplets etc. The ratings system and examples of each category are:-

Class Definition Description Examples
A1 Non-combustible No contribution to fire Glass / Stone / Concrete
A2 Limited combustibility Very limited contribution to fire Gypsum Boards with thin coverings (eg paper faced)
B Combustible Limited contribution to fire Some flame retardant treated wood products
C Combustible Minor contribution to fire Some flame retardant treated wood products
D Combustible Medium contribution to fire Most wood based panels over 390kg/m³ in density
E Combustible High contribution to fire Some wood panel systems / Plastic based insulation / Composites
F Unclassified Not tested N/A


These classes are further divided to provide information on a product’s tendency to produce smoke and flaming droplets / particles.

Smoke Generation

Smoke generation is measured for Reaction to Fire classes A2 to D. Smoke emission classifications are not provided for products with an E or F overall rating. There are three smoke intensity levels:-
s1 Emissions absent or very little
s2 Emissions with average volume intensity
s3 Emissions with high volume intensity

Fire Generation

Burning droplets/particles can inflict skin burns and cause further spread of fire. Burning droplets/particles are measured for Reaction to Fire classes A2 to E. E-rated products receive a d2 flaming droplet classification. F-rated products receive none.

There are three classes of burning droplets:-
d0 No burning droplets
d1 Slow dripping droplets
d2 High/Intense dripping droplets


As an example, a product with the resulting highest classification would have the standard: B/S1/d0. This translates to:
B - Combustible materials – Very Limited contribution to fire
s1 - Smoke emissions absent or very little
d0 - No burning droplets



Like to discuss your project with us?
We're happy to help

01460 241777