I have to comply to reaction to fire class B-s3,d1 or C-s3,d1

> Reaction to fire class B-s3,d1 or C-s3,d1

Where the requirements of B-s3,d1 or C-s3,d1 need to be met, it is essential to treat the timber with a fire retardant coating and you need to obtain a classification report based on testing.

For class B-s3,d1 and C-s3,d1, the requirements as stated on your certificate (type of timber, minimum thickness of timber, application, configuration, etc.) determine whether you meet the required reaction to fire class. Once again it is important that the façade cladding should be fixed against a back wall / substrate with fire class A1 or A2.

Insulation alone does not meet the regulatory requirements. The construction must make use of a K₂ 10 protection plate.

Facade construction reaction to fire class B-s3,d1 or C-s3,d1*

1/ Insulation material.

2/ Protective panel K₂ 10/K₂ 30 of EI 15 / EI 30

3/ Ventilated air cavity + attachment system (e.g. spruce or pine timber).

At Lemahieu Fire Protection®, the underlying battens do not require a fire retardant coating.

4/ Closed façade cladding with a fire retardant coating.

2 - 3 - 4 to be taken into account for the reaction to fire.

*Source: WTCB

Please note for open façade cladding

Open façade cladding is usually constructed with an opening of 10 mm between the façade battens. At the moment there is no standard classification for this. Lemahieu Fire Protection® will invest in testing in an attempt to enable classification for façade cladding with open joints.

It is self-evident that in the case of an open system, the battens behind the façade also need to be given a fire retardant coating.

There are currently 2 options for having a project with open cladding approved:

  1. You have an SBI test carried out specifically for a project and its application (END-use). This option is more frequently used, but takes time and money. There is also no guarantee that it will succeed.

  2. You change the design to a closed façade cladding, e.g. the LDC FARO profile:


Do you wish to receive more information or advice concerning the reaction to fire classes, don't hesitate to contact our Technical sales advisor.