Fire resistance test of cross-laminated timber joints
The results have shown various feasible CLT joints, both airtight and semi-airtight, that met the EI-90 criteria as well as other non-feasible joints that explored non-airtight solutions with a twist. The method, results and other observations during testing were analyzed and discussed to assess their feasibility and the impact of certain sources of error. The conclusion is that all joints met the EI criteria. Although straight joints have a lot of smoke emission, the critical temperatures at the top of the joint were not exceeded for the gap sizes used in this thesis.
The joint does not have to be completely covered to meet the insulation criterion (I) for gap sizes between 0-2 mm. Although connecting boards such as plywood and plaster work well to limit smoke emissions, another viable option is Rockwool. If the joints are not covered, they will emit smoke as soon as the wood starts to burn. Although the soot barely penetrated 10 mm into the Rockwool, it is uncertain how thin it can be. The integrity of the specimen was never breached in any of the tests; the E criterion was met. Moreover, when the unprotected joints emitted smoke, the temperatures never reached the requirement levels at the top of the joint on the unprotected side; the I criterion was met. In particular, the adhesive tape test was very close to its limits. It is not recommended to increase the gap size or lower the CLT height in this test.
Area: Industrial wood construction
Budget: 70,000 SEK
Time: May 2022 - October2022
Project leader: Peter Jacobsson, Martinsons/Holmen
Funding: This project is funded by TCN (funding for tests in furnace).
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