This paper presents results from two large-scale experiments where the fire spread in large open-plan compartments with exposed cross-laminated timber (CLT) was studied. In the first experiment, #FRIC-01, the ceiling was exposed, and in the second, #FRIC-02, both the ceiling and the back wall was exposed. The charring rates of the CLT, the mass loss rates and heat release rates of the CLT and wood crib were measured. In addition, the fire spread was studied visually by recording the development of the fire with several cameras. The experiments provide unique information about how exposed surfaces affects the fire dynamics and fire spread in a modern wooden compartment. Both experiments showed that the presence of exposed CLT surfaces significantly affect the fire spread rate and fire dynamics of a compartment fire.
