Polymers 2021 , 13 , 709
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Table6. ANOVA table for Col_3 Weight loss by Col_2 thickness.
Source
Sum of Squares
Df
Mean Square
F-Ratio
P-Value
Between Groups Within Groups
5.78793E6 4.4566E8 4.51448E8
2
2.89396E6 3.80906E6
0.76
0.4701
117 119
Total (Corr.)
The ANOVA table decomposes the variance of Col_3 Weight loss (%) into two compo- nents: a between-group component and a within-group component. The F-ratio, which in this case equals 2.0454, is a ratio of the between-group estimate to the within-group estimate. Since the P-value of the F-test is greater than or equal to 0.05, there is not a statistically significant difference between the mean Col_3 Mass loss (%) from one level of Col_1 (heat flux) to another at the 5% significance level. Additionally, since the P-value of the F-test is greater than or equal to 0.05, there is not a statistically significant difference between the mean Col_3 Weight loss (%) from one level of Col_2 thickness to another at the 5% significance level. 3.2. Determination of Critical Ignition Temperature Critical ignition temperature was monitored by means of thermocouples placed below and above the test sample. The increase in temperature was monitored on the upper surface of the 15 mm OSB, which was exposed to a direct radiant heat flux of 44, 46, 48 and 50kW.m − 2 for 300 s. The OSB boards with 15 mm thickness are the most commonly used building material in the construction of soffits. The first set of experiments with a heat flux density of 44 kW.m − 2 for the period of 300 s resulted in an ignition time of 142 s (Table 7). The temperature at the bottom surface of the board rose minimally (Figure 8). The time to ignition (142 s) was the longest compared to other values obtained at higher heat fluxes (Table 3). The ignition temperatures obtained from the experiments varied. It is not possible to find the correlation with other parameters.
Table 7. Time-to-ignition and ignition temperature at the upper and lower surfaces of a 15 mm thick OSB sample corresponding to the individual radiant heat flux densities.
Temperature ( ◦ C)
Heat Flux (kW.m − 2 )
Time to Ignition ( ◦ C)
Direct Side of Heat
Opposite Side
44 46 48 50
142
287 358 252 319
34 25 26 27
70 64 58
Figure8. Temperature dependence of the upper surface of an OSB with a thickness of 15 mm on the exposure time to the cone calorimeter.
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