Powdered oyster shells (Ostreidae) and egg shells mixed with varnish as fire-retardant on plywood

Abstract

This paper investigates the effect of powdered oyster shells (ostreidae) and egg shells mixed with varnish as fire retardant on plywood. The data supports and validate that powdered oyster shells (ostreidae) and egg shells are comprised of 95- 98% calcium carbonate which suppress, reduce, or delay the combustion of the material to a significant degree. The three treatments were prepared (A- 5 grams of powdered oyster shells (ostreidae) and 5 grams of egg shells + 150 ml varnish, B- 10 grams of powdered oyster shells (ostreidae) and 10 grams of egg shells + 150 ml varnish, and C-15 grams of powdered oyster shells (ostreidae) and 15 grams of egg shells + 150 ml varnish), D - commercial fire retardant varnish as positive control, E - pure classic varnish as negative control and F - plain plywood with 18 replicates including the control variables. The 18 replicates were tested using blowtorch with the fixed time of 30 seconds in treatment A, B, E and F while 60 seconds in treatment C and D in the burning of plywood. Based on the fire-resistant rate among 6 treatments, the shortest time the fire stop is considered the most effective. There is a significant difference in the fire-resistant rate among different treatments, p=0.001. All treatments were effective, but treatment B and C was the most effective. The results revealed that using large amount of powdered oyster shells (ostreidae) and egg shells resulted to a higher probability to prevent spreading of fire. Also, it slows down the tracking of fire due to calcium carbonate content.