Fire safety of cross-laminated timber

Summary

Cross-laminated timber (CLT) panels are used as load-bearing wall and floor massive wood elements and have become one of the most popular and dominant product for innovative and high quality modern timber buildings. However, because of severe concerns about the fire behaviour of CLT, its use has strongly been questioned. The main concern is the risk of a so called “second flashover” due to char layer fall-off and thus the scenario that CLT buildings would possibly not be self-extinguished even after all contents (furniture, drapery, books…, etc.) in the room have been completely consumed by the fire. The exposed CLT could continue to burn by itself until perhaps the eventual collapse of the structure. The project aims at the development of a new generation of "heat and fire-safe" PUR adhesives. The main objective is the demonstration that CLT bonded with the new PUR adhesives does not show significant char layer fall-off and thus there is no risk for second flashover.

Support

This project is carried out in collaboration with Henkel AG and is kindly supported by Innosuisse, the Swiss Innovation Agency.