Fire Performance Testing

The Euroclass system of classification is made up of stacked levels, i.e. as you move up a class (e.g. D to C), the compliance rules get more stringent. For building materials and components, classification rules are based on the following test evidence: 

- Resistance to Fire (stopping fire from spreading) and
- Reaction to Fire (smoke and heat emisson) 

Below provides a brief insight into how grades are awarded:

- If a product has not been tested, or it has failed to meet any of the requirements of Class A1 to Class E, then it will be classified as Class F.  
- Products that have significant contribution to fire but resist a small flame for a short time  are Class E.  Those with a contribution to fire but a greater resistance to a flame, would be Class D.  
- Products that meet more stringent requirements than Class D with limited contribution to fire fall into Class C. This is always followed by additional classification for smoke and burning droplets.  
- Highly resistant materials would be Class B. This is also followed by additional classification as above. 

- If construction products produce no contribution to fire (but have the potential to produce some smoke or flaming droplets) this falls into Class A2. this is also followed by additional calssification for smoke and droplets. 
- Materials that cannot contribute to a fire at any stage, including a fully developed fire, can be awarded Class A1. This would never be combined with additional classification. 

A1 vs A2 Materials 

A1 materials are completely non-combustible while A2 materials have very limited combustibility. While A1 materials have no contribution to fire, A2 materials have a limited contribution to fire.

Specifying Materials 

To be used in a building, materials will usually need to pass the British Standards relating to Fire Protection. In particular, only A1 and A2-rated materials can be specified in external walls due to their non-combustible nature. The most stringent tests must be passed in order for construction products to reach a Class A rating.  

Smoke Emission during Combustion

The second classification in the Euroclass system is related to smoke emission. The rating S1, S2 or S3 indicates highest to lowest performance. Smoke classification is not provided for products from E to F.  

The ratings denoted by 'd' indicate the level of production of flaming droplets or particles during combustion. F-rated products are not given a "d" rating. Additionally, A1-rated materials are not given smoke emission or flaming droplet rating as it is mandatory that they do not contribute to fire growth or spread, and will not produce any smoke or droplets to receive this classification.

- S1 - Very Limited smoke
- S2 - Limited Smoke
- S3 - A lot of Smoke

- D0 - No Burning Droplets/Particles
- D1 - Limited Burning Droplets/Particles
- D2 - Unlimited Burning Droplets/Particles

Source: https://www.mydek.com/insights/what-do-a1-and-a2-mean