Production possibilities for structurally protected plywood by chemical fire-retardants
Research subject and fields:
The aim of our work was to produce panels from laminated wood protected by chemical fire-retardants. Such produced panels should maintain their physical and mechanical properties above the minimally prescribed standards, whereas, at the same time improving their fire-retardant properties. The materials used were beech veneer, urea formaldehyde glue, and for the structural protection, borax and boric acid in proportion 1:1 were used. The chemical fire-retardants were deposited by sinking the veneer in their water solution concentration of 6, 10 and 14 %. Also, for reasons of comparison, laminated wood based panels were produced without the addition of fire-retardant chemicals. The physical and mechanical properties as well as fire-retardance were tested on such produced panels. With regards to the various methods for the evaluation of fire-retardance, a certain method was chosen, which was sufficiently "severe", and which used samples of small dimensions during the research. This method is called the fire-tube method. The research results of the physical and mechanical properties of the panels have shown that the added fire-retardance chemicals in the stated concentrations, do not significantly influence these features, and that they are above the minimally prescribed standard values according to which the research was made. The results of the fire-retardance research, using the fire-tube method, have shown that the best results were achieved with the laminated panels structurally protected with 14 % water solution fire-protected substance, even though panels with 10 % solution have shown solid results. Fire-retardance of panels with 10 % borax and boric acid, can be additionally increased if the panels undergo a surface protection in addition to the structural one.