The air-tightness of the building components (wall, ceiling and roof) is essential in many aspects as indoor climate, noise, energy balance and structural defects.
Inadequate air-tightness has as consequences low thermal protection, low surface temperature, damage to the structure, mould, draughts and increasing energy demand.
A CLT (cross laminated panel) panel, during the service, is exposed to different conditions. It is product with 10-12% Moisture content (MC), but during the construction can absorb building moisture and domestic ventilation can dry out CLT. The fluctuation of MC in CLT is connected with the changing in shape of the panels (swelling and shrinkage) and consequently the stresses in the panels.
Air-permeability test has been conducted in laboratory according to the standard EN EVS 12114/2000. The test machinery consists of the following parts: air compressor, air flow regulator, measuring the air flow with integrated flow adjustment valve, manometer, air filter with air pressure difference regulator, flow pipes, metal frame box.
Different pressures were applied in different steps (n.7) as reported in the standard.
This paper explains an air permeability test performed on spruce samples (n. 21 dimensions 110*110*6 mm3 MC 9.2%) in different configurations (n.3 single samples, n.3 with two lamellas glued together in crosswise direction) and with different holes (n.3 with 2 mm diameter and n.3 with 6 mm diameter) to simulate the cracks. It has been possible to see how the air flow rate changes from the samples without holes to those with holes.
In the cases of single samples and the 2 layers glued, test showed the completely tightly of them. For the drilled samples, how the flow rate doesn’t increase in proportion to the hole´s surface (2.5 for the flow instead of 9 for the holes) and the ratio between the flow and the hole is higher for the smaller holes (0.53 and 0.13). For further studies it was proposed to study a 5 layers CLT panel across the edges.
Keywords: Cross laminated timber, cracks formation, water vapour resistance
Authors
Luciani G.
Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
Horta R.
Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
Kallakas H.
Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
Kers J.
Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
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