Effect of various fire retardants on Brinell hardness of some wood

This study was performed to determine the impact of impregnation materials on the Brinell hardness of varnished wood materials. For this purpose, test specimens prepared from Scotch pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis Lipsky), which met the requirements of ASTM D 358, were impregnated according to ASTM D 1413-07 with borax, boric acid, zinc chloride, and di-ammonium phosphate by a vacuum technique. After impregnation, the surfaces were coated by cellulosic, synthetic, and polyurethane varnishes in accordance with ASTM D 3023. The Brinell hardness of the specimens after the varnishing process was determined in accordance with ASTM D 4366. According to the result of the tests, the highest Brinell hardness (135.40 kpm/m²) was determined in oriental beech samples, cut tangentially, impregnated with di- ammonium phosphate, and varnished with polyurethane. The lowest Brinell hardness (23.20 kpm/m²) was determined in Scotch pine control samples, cut radially and synthetically varnished.