Fire behaviour of cross-laminated solid timber panels

Cross-laminated solid timber panels represent an interesting technical and economical product for modern timber structures. The use of large prefabricated cross-laminated solid timber panels for load-bearing wall and floor assemblies has become increasingly popular in particular for residential timber buildings. The fire behaviour of cross-laminated solid timber panels has been experimentally and numerically studied during two different ongoing research projects carried out at the Institute of Structural Engineering of ETH Zurich, Switzerland and the Trees and Timber Institute CNR-IVALSA in Trento, Italy. The paper presents the main results of the experimental and numerical analyses. Particular attention is given to the comparison of the fire behaviour of cross-laminated solid timber panels with homogeneous timber panels. The results of the analysis have shown that the fire behaviour of cross-laminated solid timber panels depends on the behaviour of the single layers. If the charred layers fall off, an increased charring rate needs to be taken into account. The same effect is observed for initially protected timber members after the fire protection has fallen off. Thus the fire behaviour of cross-laminated solid timber panels can be strongly influenced by the thickness and the number of layers. Further vertical structural members (walls) may show a better fire behaviour in comparison to horizontal members (slabs).