The treatment with fire retardant chemicals is the most effective process to protect wood and wood based products from fire is. Therefore, use of fire retardant chemicals has been increased. However, the fire retardant chemicals have an effect on other physical, mechanical and some technological properties of the materials treated with them. In this study, it was examined that the effect of fire retardant on physical properties of plywood. Alder (Alnus glutinosa subsp. barbata ) and Scots pine (Pinus sylvestris L.) were used as wood species; zinc borate, monoammonium phosphate and ammonium sulfate were used as fire retardant chemicals and UF resin was used as adhesive. The veneer sheets were treated with immersion method. Physical properties of the plywood panels such as thickness swelling and water absorption, density and equilibrium moisture content of the panels were determined according to TS EN 317, TS EN 323-1 and TS EN 322, respectively. Thickness swelling and water absorption values of panels produced with the veneers treated with fire retardant chemicals were less than those of control panels for 2 h. However, there is no statistical difference in these results for 24 h. In addition, it was found that the density values of panels treated zinc borate was the highest in the all groups for Scots pine.
Alder, Fire retardant, Physical properties, Scots pine