This thesis describes a series of 5 tests that were conducted at Carleton University Fire Research Laboratory to assess the contribution of Cross Laminated Timber (CLT) panels to the development, duration and intensity of room fires. The tests were conducted in rooms constructed from 105 mm thick 3-Ply CLT panels and measured 3.5m wide by 4.5 m long by 2.5 m high. Propane and furniture fires were used with the CLT panels in protected and unprotected configurations. Data was collected on Heat Release Rate (HRR), room temperatures and charring rates. In protected configurations, no noticeable contribution was observed from the CLT panels, however in unprotected configurations, the CLT panels contributed to the fire load and increased fire growth rates and energy release rates. When charring advanced to the interface between the CLT layers, the polyurethane based adhesive failed resulting in delamination. Delaminated members contributed to the fire load and exposed uncharred timber which increased the intensity and duration of the fire. When delamination occurred, the fire in unprotected rooms continued to burn at high intensity well after the combustible contents in the room were consumed by the fire. These fires were extinguished as they could have resulted in structural failure of the test rooms.
This paper documents the findings of a series of full-scale room fire tests, which includes tests on fully protected, partially protected CLT rooms as well as light-frame timber/steel rooms under real natural fires, aiming to investigate the fire behaviour and performance of CLT panels as an increasingly popular engineered wood product and to compare it to the performance of more traditional construction methods. Results show that the CLT panels when left unprotected get involved in the room fire as part of the combustible contents, responsible for over 60% of total heat release in the fully unprotected CLT room and double the heat release rate of a fully protected room fire where the CLT does not contribute. Partially-protected CLT rooms also demonstrates various levels of fire contribution. The amount of CLT exposure is also related to the occurrence of re-ignition and a second flashover after all the movable fuels are consumed. The behaviour of CLT delamination and charring as well as the performance of gypsum boards in fire are also discussed.