# Fire Behavior of Wood-Glass and Jute-Glass Hybrid Laminates Manufactured by Vacuum Infusion
## 3 Results and Discussion
The amount of total smoke released during the burning of materials such as wood and jute, which have organic compounds in their composition, also includes the release of carbonized particles, organic vapors, and gases, and is expected to be greater than glass mat, as it has no smoke release [20]. Figure 6 shows the results of the percentage of reduction in transmittance of the laser in the exhaust air flow. This information is used by the instrument to process all data regarding smoke production. The specific extinction area (SEA, m\({}^{2}\)/kg) is the ratio of smoke production to specimen mass loss averaged over the test duration. This parameter is interesting, compared to the others reported on the smoke produced, because is related to the mass of the sample and not to its exposed surface. Using this measure, it is possible to compare samples that have significantly different masses, like those in this study. According to this process, the polyester resin has the highest SEA value of 1227 \(\pm\) 8 m\({}^{2}\)/kg. On the contrary, the samples G5, J5, and GJGJG are fully comparable, with values around 825 m\({}^{2}\)/kg, and the best result was obtained by WGWGW, with 697 \(\pm\) 31 m\({}^{2}\)/kg. This is mainly due to the fact that the WGWGW sample was the heaviest of the laminates. Figure 4: Total heat release (THR) as a function of time for each group analyzed (**A**) and average maximum values for THR (**B**). Different letters above the errors in each group represent a statistical difference. Figure 5: Total smoke release as a function of time for each group analyzed (**A**) and average values for total smoke release at the end of the test (**B**). Different letters above the errors in each group represent a statistical difference. Burning materials can result in the emission of gases that are harmful to the environment and human health. Initially, during incomplete combustion, carbon monoxide (CO) and soot are released. Later, these gases are oxidized to form carbon dioxide (CO\({}_{2}\)) and water, representing the complete combustion of the material [32]. Figure 7A,B show the results of the measurements of the percentages in the instrument's exhaust air of carbon monoxide (CO) and carbon dioxide (CO\({}_{2}\)) during the combustion of the different laminates. The results show that the wood-glass and jute-glass composites showed more than a 50% reduction in the CO and CO\({}_{2}\) maximum peaks of emissions compared to polyester resin. The best performance was obtained by the G5 sample. The lower CO and CO\({}_{2}\) values observed for the G5 hybrid laminate in Figure 7 can be attributed to the inherent properties of glass fibers. Glass fibers are non-combustible and can act as an effective barrier to heat transfer, thereby reducing the rate of combustion and the subsequent emission of gases like carbon monoxide (CO) and carbon dioxide (CO\({}_{2}\)) [33]. Therefore, the inert nature of glass fibers ensures minimal contribution to gas emissions during the combustion process, which explains the lower values of CO and CO\({}_{2}\) observed for the G5 laminate compared to other hybrid laminates containing natural fibers. In addition, another two-component laminate, GJGJG, despite having glass sheets on the faces, showed higher CO/CO\({}_{2}\) emissions than the single-component laminate, G5. This is probably related to the configuration of the laminate, since jute fabric is used between the glass mats [13]. Figure 7B shows a significant discrepancy in the largest error bar defined by the 95% confidence interval for the carbon monoxide values between neat polyester and the hybrid laminates incorporating jute, wood, and glass. A possible mechanism to explain the observed discrepancy could be related to the enhanced char formation and insulation properties conferred by the natural fibers and wood veneers [34]. During combustion, the jute and wood components may contribute to the formation of a more robust and heat-resistant char layer, which could potentially reduce the rate of carbon monoxide emission.