An Introduction to Reaction to Fire

What is Reaction to Fire Testing?

Reaction to fire testing examines the characteristics, such as combustibility, of building materials to determine their contribution to the development and spread of a fire. Materials can be classified under BS EN 13501-1 according to their reaction to fire and this is determined with a series of tests.

What test methods are used in Reaction to Fire Testing?

Single Burning Item (SBI) – BS EN 13823:2020

This procedure, likely the most recognisable of the tests, specifies a method of test for determining the reaction to fire of construction products when exposed to thermal attack by a single burning item.

Non-Combustibility – BS EN ISO 1182:2020

This test identifies products that will not, or not significantly, contribute to a fire, regardless of their end use. This test has been developed to identify construction products which produce a very limited amount of heat and flame when exposed to temperatures of approximately 750°C.

Small Flame – BS EN ISO 11925-2:2020

The Small Flame test method determines the potential maximum total heat release of a product when completely burned, regardless of its end use. This determines the absolute value of the heat of combustion for a product without accounting for inherent product variability.

Calorific Value – BS EN ISO 1716:2018

This method specifies a test for determining the ignitability of products by direct small-flame impingement under zero impressed irradiance using vertically oriented test specimens.

Is a product required to use each test method to determine its classification?

No, there are mandatory test methods to be completed depending on the classification being sought.

Classification	BS EN ISO 1716	BS EN ISO 1182	BS EN ISO 13823	BS EN ISO 11925-2
A1	Mandatory	Mandatory	x	x
A2	Or	Or	Mandatory	x
B	x	x	Mandatory	Mandatory
C	x	x	Mandatory	Mandatory
D	x	x	Mandatory	Mandatory
E	x	x	Mandatory	Mandatory

What does a reaction to fire classification look like?

A product’s reaction to fire classification is broken down into three characteristics: Combustibility, Smoke Production, and Flaming Droplets. These are displayed as follows…

Combustibility

A1 – Non-combustible materials that do not contribute to the development of a fire.

A2 – Materials with limited combustibility that do not contribute to the development of a fire.

B – Combustible materials with limited contribution to fire development.

C – Combustible materials with minor contribution to fire development.

D – Combustible material that contributes to fire development.

E – Combustible materials that will only resist a small flame for a few seconds.

F – Materials that have not met the minimum requirements of class E.

Smoke Production

s1 – Little or no smoke production.

s2 – Moderate amount of smoke production.

s3 – Substantial amount of smoke production.

Flaming Droplets

d0 – No flaming droplets or particles

d1 – Some flaming droplets and/or particles

d2 – Quite a lot of flaming droplets and/or particles

Example Classification

If a product received a classification of B-s1,d0 this would translate to the product having limited combustibility (B), low smoke production (s1), and no flaming droplets (d0).

To learn more about the BS EN 13501 reaction to fire classification system, test methods or to organise reaction to fire testing for your product, talk to our team by clicking here.