The paper deals with testing fire resistance of a vertical wooden building construction made of CLT panels subjected to the medium-scale test of the fire resistance. A model test of fire resistance with the ceramic radiation panel as the radiation heat source, with achievable temperature of radiation surface of 935°C at maximum was used. The aim of the experiment was to assess the experiment sample whether it meets the request of the thermal insulation and integrity under thermal loading of the model fire for 30 min. The test resulted in the increase of temperatures on observed thermocouples and assessment of the integrity on the unexposed side of the CLT panel. The construction clearly resisted the effects of the radiation heat during 30 min and maintained the observed criteria of fire resistance. Charred layer of the CLT panel created on the surface of the exposed side in the thickness of 20 mm inhibited the heat transfer into the further layers of construction.
To explore the feasibility of hem-fir for CLT products, this work addressed the exploratory and pilot plant studies of hem-fir cross-laminated timber (CLT) products through mechanical tests. The hem-fir lumber was procured and then stress-graded based on dynamic modulus of elasticity (MOE). The resulted 5-ply prototype CLT products were then tested non-destructively and 3-ply pilot plant hem-fir CLT was tested destructively. The results showed that bending performance of hem-fir CLT panel can be predicted. Considering cost-competitiveness and end applications of hem-fir CLT products, the panel structure can be optimized based on the stress-graded data of hem-fir lumber.