Facade fires have shown how critical material choice is. We explain the difference between A2 and class B composite panels, regulatory requirements and the measures needed for a safe facade.
Facade fires around the world have clearly shown how decisive the materials in a building envelope are for life safety. Fire safety in cladding must be addressed on three levels: the fire rating of the cladding, the insulation material and fire barriers.
What do fire classes mean?
Building materials are classified from A1 to F under EN 13501-1. Classes A1 and A2 denote non-combustible materials and class B denotes flame-retardant ones. Smoke production (s1–s3) and flaming droplets (d0–d2) are also stated.
A2 composite panels
The core of an A2 panel contains a high proportion of mineral filler and does not contribute to fire spread. A2 panels should be preferred especially for:
- High-rise buildings (over 28.5 m),
- Hospitals, schools, hotels and assembly buildings,
- Buildings with limited escape routes.
Class B (FR) composite panels
Class B panels are flame-retardant and offer a safe, economical option for low- and mid-rise buildings. They must be used together with code-compliant fire barriers and non-combustible insulation.
Why not use polyethylene (PE) core panels?
PE core panels are cheap, but the core is a fully combustible plastic that can cause fire to spread rapidly up a facade. Mercan does not use PE core panels on facades.
Checklist for a safe facade
- Request the panel’s fire classification report (EN 13501-1).
- Use A1 stone wool insulation behind the cladding.
- Install horizontal fire barriers at every slab edge.
- Do not neglect fire-stopping details around windows.
- Avoid combustible components in the substructure.
Safety on the facade should never be negotiable. On our composite cladding projects we only use documented A2 and B rated panels.
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