Impacts of some chemicals on combustion properties of impregnated laminated veneer lumber (LVL)

Abstract

The objective of this study was to investigate the effects of zinc chloride (ZnCl2) and borax (Na2B4O7·5H2O) on combustion properties of laminated veneer lumbers (LVLs) with two, three and four-layered, produced from white oak (Quercus alba) and chestnut (Cestanea sativa Mill.) woods. Veneers obtained for LVL were impregnated according to ASTM-D 1413. Veneers applied vacuum method were dried and bonded with poly(vinyl) acetate (PVAc) and D-VTKA polyurethane-based adhesives. The combustion test was performed according to the procedure defined in the ASTM-E 69 standard. The results indicated that the highest weight loss of LVL (43.1 g) was observed in unprocessed weigh wood samples. The lowest O2 consumption ratio was in borax-impregnated LVL samples with Desmodur-VTKA, with a ratio 20.4%. The highest CO ratio observed in LVL control samples was 2834.7 ppm, the highest temperature measured in borax-impregnated control LVL was 398.5 °C, the highest ash ratio was measured as 82.4%, however NOx and SOx emissions (oxides of nitrogen and sulfur) could not be measured, because heat did not go up to 1000 °C. As a result, borax was found to be an effective fire-retardant chemical in LVL. In conclusion, it can be recommended as a fire-retardant building material.