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Understanding fire classifications
What do A1 and A2-s1,d0 actually mean?
Reaction-to-fire classifications describe how a construction product contributes to the development of fire under defined test conditions. They form part of the European classification system set out in BS EN 13501-1.
Euroclass A1
A1
No contribution to fire
A1 is the highest reaction-to-fire classification. Products achieving this classification are considered non-combustible and make no contribution to fire under the applicable classification criteria.
Stamisol A1
Euroclass A2-s1,d0
A2-s1,d0
Very limited contribution to fire
A2 products make a very limited contribution to fire. The additional classifications provide further information about smoke production and flaming droplets or particles.
Stamisol Safe One
s1
Smoke production
The lowest smoke production category.
d0
Flaming droplets / particles
No flaming droplets or particles under the relevant test conditions.
A1 and A2-s1,d0 are not interchangeable. These classifications provide useful information when comparing materials, but they do not establish the fire performance of an entire external wall. Safe One is classified A2-s1,d0; it should not be described as an A1 or non-combustible membrane.
Material evidence / system evidence
The complete façade must be considered.
The complete façade must be considered, including the cladding, insulation, cavity, supporting structure, membranes, fixings and cavity barriers. The classification of an individual membrane should never be interpreted as proof that the overall façade meets every applicable fire safety requirement.
The supporting construction, exposure conditions and installation details all form part of the assessment. Product-specific evidence must be considered against the proposed application.
Not an isolated decision
One membrane.
A complete external wall.
Cladding
Insulation
Cavity
Supporting structure
Membranes
Fixings
Cavity barriers
Installation details
Applying the classification
From a rating to a specification.
Stamisol A1 is Euroclass A1, with defined substrates, supporting construction and installation requirements. Partially open façade joints are limited to a maximum gap of 10mm, subject to the relevant documentation.
Stamisol Safe One is Euroclass A2-s1,d0 and has W1 water-tightness performance. It is intended for specified ventilated façade applications, with open joints up to 50mm or 50% open area, subject to the manufacturer's conditions.
Neither classification is an automatic recommendation for a particular building type. The final choice should always be based on the project specification and the relevant manufacturer documentation.
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