Fire classes simply explained: what do A, B and flame-retardant mean?

How well does a fireproof mat really protect? You often read terms such as “fire class B”, “flame-retardant” or “non-combustible”. Here we explain what the fire classes mean, which standards are behind them and what this means for the FireMat.

Fire classes at a glance

Fire classes, more precisely building material classes, describe how a material reacts to fire. In Europe, DIN EN 13501-1 applies. It divides building materials into these classes:

• A1 and A2: non-combustible, for example stone, concrete, glass or metal.
• B: flame-retardant, very limited contribution to fire.
• C: flame-retardant, limited contribution to fire.
• D: normally flammable, medium contribution to fire.
• E: normally flammable, briefly withstands a small flame.
• F: no performance determined.

There are also additional classifications for smoke (s1 to s3) and flaming droplets (d0 to d2).

The old classes according to DIN 4102

In the past, only DIN 4102-1 applied in Germany. Its terms are still well known today:

• A1, A2: non-combustible
• B1: flame-retardant
• B2: normally flammable
• B3: highly flammable

The classes cannot be transferred one to one. Roughly, B1 corresponds to the European classes B and C, B2 to classes D and E.

How is testing carried out?

For class E, a test with a small flame according to DIN EN ISO 11925-2 is sufficient. For classes B to D, a larger fire test is added, the SBI test. There are separate tests for A1 and A2.

What applies to the FireMat?

The FireMat is made of Panox and para-aramid. These fibres do not melt, do not drip and are self-extinguishing. They withstand up to 300 °C continuously, the Gold Edition even up to 800 °C.

The FireMat is certified by TÜV SÜD according to DIN EN ISO 11925-2. The certificate states that it was tested and recognised as flame-retardant. Testing was based on DIN EN ISO 11925-2 with 30 seconds of flame exposure, the stricter variant of the test. The certificate covers the Black, Silk, Silk-A, Green Silk and Gold Editions. You can find it among our certificates.

Important: The FireMat is not a building material in the sense of building law. It is therefore not expressly approved as a substitute for prescribed measures, such as the floor plate in front of a wood-burning stove. As a protective mat for appliances and surfaces and as an addition on top of the floor plate, however, it is ideal.

What is “flame-retardant” sufficient for?

• Under electrical appliances: In offices, DGUV Rule 115-401 requires a non-combustible base for coffee machines and kettles. More in Fireproof mat for electrical appliances.
• On the induction hob: as protection against scratches and boil-overs. More in Induction protection mat.
• For crafts and soldering: as a work mat against sparks and heat.

Where the law requires a non-combustible class A building material, for example on the floor in front of fireplaces, glass, tile, stone or steel is needed. More in Spark protection mat for the fireplace.

Frequently asked questions

What is the difference between fireproof and non-combustible?

“Non-combustible” is a building material class (A1, A2). “Fireproof” is an everyday term. It usually means that the material does not continue to burn and withstands high temperatures.

What does fire behaviour E mean?

The material is normally flammable. It withstands a small flame for 15 seconds without the fire spreading far.

Conclusion

Fire classes show how a material reacts to fire. The FireMat is certified by TÜV SÜD according to DIN EN ISO 11925-2 and is therefore ideal as a protective mat for electrical appliances. Where building law requires non-combustible building materials, it complements them but does not replace them.

You will also find further technical terms in the glossary FireWiki.