We are heading towards a new year and with that also a new version of FEM-Design v21. A major new feature is the Cross Laminated Timber CLT Fire Design module.

Having wood as a structural material is becoming more and more common, but it also raises demands on Designers to ensure building structures’ capacities,  in all load limits, to include fire design. We are now pleased to announce that fire sizing of CLT will be possible in FEM-Design v21.

So how does this work?

The program uses a method where the cross-sectional area is reduced with regard to the charring of the wood material. This is similar to the method implemented for beams and columns (timber bars) already in FEM-Design. You start by setting the duration of the fire, second defining which sides are exposed to the fire and then choose any fire protection.

CLT Fire Design Software

To deal with failures of delaminating layers in the KL board ,due to the deteriorating properties of the adhesive in the event of a fire, a multiplier on the charring speed is used. It is also possible to ignore layers that fall below a certain thickness. This can otherwise lead to a favourable behaviour for thin or partially charred layers. The reduced area is calculated and what remains of the KL panel is checked against the usual checks.

CLT Reduced Panel Fire Design

Regarding results and documentation, detailed formulas for all design checks are reported. In addition to this, the stress distribution across the reduced cross-section is also shown in a clear and pedagogical manner.

Cross Laminated Timber Fire Design Software

Do not hesitate to contact us if you have any questions and if you would like to find out more about the CLT Module in FEM-Design please click here.