What is Reaction to Fire?

Reaction to fire is the response of a product in contributing, by its own decomposition, to a fire to which it is exposed. It relates to the combustibility and ignitability of building materials and can be used to determine how much energy they contribute to the growth of a fire. It is therefore important during the early stages of a fire. 

How is Reaction to Fire Classified and Tested?

Reaction to Fire is classified through the European Standard BS EN 13501-1 (also known as Euroclasses).  

This standard classifies construction products and building elements from A through to F and determines their reaction to fire performance using data from a combination of 4 small scale reaction to fire tests, which consider extent of burning and damage, flame spread, heat release, smoke production and flaming droplets. For all construction products, the tests take into consideration a fire, initiated in a room, which can grow and eventually reach flashover.

  1. The Ignitability Test represents the ignition stage of a fire and evaluates the ignitability of a product under exposure to a small flame. This test is relevant for classes B through to E.
  2. The Single Burning Item Test represents the growth stage, eventually reaching flashover, and evaluates the potential contribution of a product to the development of a fire, under a fire situation simulating a single burning item in a room corner near to that product. This test is relevant for classes A2 to D.
  3. The Non-Combustibility and Heat of Combustion Tests represent the post-flashover, fully-developed fire stage and are relevant for classes A1 and A2. The Non-Combustibility Test identifies products that will not, or not significantly, contribute to a fire, whilst the Heat of Combustion Test, also known as the Bomb Calorimeter Test, determines the potential maximum total heat release of a product when completely burning.
In accordance with the Euroclass system, there are also additional classifications for the production of smoke and flaming droplets/particles for classes A2 through to E.

Why is Large-Scale Reaction to Fire Testing Important?

At Kingspan, we believe that reaction to fire performance should not be assessed through small-scale tests alone but should be determined by large-scale system tests.

This is because the fire performance of a cladding system depends not only on the performance of individual materials, but also on the interaction of all the components in that system in response to a fire.

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