ISOVER HVAC/Technical Products – Fire Classification
How materials behave in the early stages of a fire, from ignition to flashover (the spontaneous ignition of hot smoke and gasses) needs to be assessed at design stage for buildings and also for plant and equipment.
Euroclasses, a new European harmonised classification system for materials’ reaction to fire is now in place and is intended to replace the old national standards, such as British Standards. Building Regulations in England, Wales and Scotland now incorporate Euroclass classifications. Whilst currently, the Euroclass fire classification covers only materials used in building structures, many of these materials are also used in plant and equipment and it is proposed to extend the Euroclass system to cover building equipment and Industrial Installations. This will help to compare the reaction to fire of different thermal insulation materials. The classification levels are A1/A2 (completely non-combustible) B, C, D, E and F. A1/A2 corresponds to the safest situation. E would be the most dangerous situation and F would mean not classified.
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ISOVER glass mineral wool is totally non-combustible and completely fire safe, achieving Euroclass A1 fire rating when classified in accordance with BS EN 13501 – 1.
One of the most important issues studied under reaction to fire performance is the potential for flashover to occur which can lead to a fire spreading uncontrollably. ISOVER glass mineral wool is not susceptible to flashover.
The base mineral wool of ISOVER duct products has a Euroclass A1 fire rating when classified in accordance with BS EN 13501 – 1. Additionally, the factory-applied aluminium foil facing meets the highest standards required by BS476: Part 6 ‘Fire Propagation’ and BS476: Part 7 ‘Surface Spread of Flame’. The foil facing is therefore rated ‘Class 0’ to the Building Regulations.
The Euroclass will be indicated on the product within the CE Mark label.
Transpositions for England and Wales
The Euroclass system permits wider and more comprehensive differentiation of products for their fire performance than the ‘old’ British Standard System. This makes it a welcome tool for specifiers.
Reaction to Fire
In broad terms, the transpositions for Reaction to Fire can be summarised as:
Smoke and flaming droplet risk
(1) In the EU classification system for Reaction to Fire, a construction product will be classified as Euroclass A1, A2, B, C, D, E or F depending on its tendency for ‘burning’.
(2) The product testing will provide data, represented by the signs S1, S2, or S3, which indicate the tendency to release smoke. Smoke causes over 60% of deaths in fire across the EU. The measurement of smoke release has been put into these 3 broad bands that can be translated as ‘a little or no smoke’ S1 – ‘quite a lot of smoke’ S2 – ‘substantial smoke release’ S3.
(3) Some construction products, like these made of polystyrene, can melt and ignite to form Flaming Droplets. Wooden products, on the other hand, will tend to char before the char falls away as Flaming Particles to expose more material.
These ‘flaming droplets/particles’ will tend to initiate new fires away from the original point of ignition and must be considered when the products are used horizontally in ceiling or roof applications. The classification system ranks the level of release of Flaming Droplets/Particles as d0 (none), d1 (some) and d2 (quite a lot).
Using the information
For specifiers, it may be critical in the design, hazard and risk evaluation, to assess the differences between, for example,
A class C – s1, d0 product and a B – s3, d2 product. Is the B or C burning data the dominant issue, or is the high smoke or is the high smoke production a more vital characteristic?