## 3 Results and Discussion
### Primary Processing Scattering Light Distribution According to Smoke Particle Color
Figure 9 shows the results obtained by applying criterion I (shown in Table 1). In Figure 9a, the y-axis represents the ratio of the forward and backward scattering ratio for 15\({}^{\circ}\)/165\({}^{\circ}\) to the 0\({}^{\circ}\) light extinction signal. The results confirm that for filter paper, as the OD increases, the value is included within the range of \(\pm\)10. However, as this convergence occurs only after the detector is activated (\(x>1\)), it cannot be considered differentiating data. In addition, as there is no such regularity in the results for the other combustibles, it is difficult to find meaning in the results or the method of analysis. Figure 9b shows the ratio of the forward and backward scattering ratios for 30\({}^{\circ}\)/150\({}^{\circ}\) to the 0\({}^{\circ}\) light extinction signal. Although this plot does not show a definite trend, the results obtained by analyzing each experiment confirm that the white smoke from filter paper has a positive value with a probability of 80%, as a negative signal was found in only 3 of 15 experiment repetitions. In the end, criterion I was deemed to have limited usefulness in distinguishing smoke colors through the distribution of light scattering and absorption signal measured inside the LSC. Figure 8: Distribution of ratios of light extinction and total light scattering according to combustibles. Figure 10 shows the asymmetry ratio results obtained by calculating the ratio of forward over backward scattering (criterion II). In Figure 10a, the y-axis represents the results, using \(15^{\circ}\) as the forward scattering angle and \(165^{\circ}\) as the backward scattering angle. The filter paper results are widely distributed in the shape of a sector symmetrical to \(y=0\). For kerosene, the values range from \(-5\) to \(0\) from the initial point of smoke generation until after the activation of the photoelectric smoke detector. The signal for PU tends to appear at the same tendency as that for filter paper and kerosene. Therefore, if a signal falls outside the range from \(-5\) to \(0\), it can be determined that it is not due to a smoke particle generated from kerosene. Figure 10b shows the ratio using \(30^{\circ}\) as the forward scattering angle and \(150^{\circ}\) as the backward scattering angle. The results confirm that the values for filter paper range from \(-0.5\) to \(+0.5\) as the OD increases; however, it is difficult to classify the data in the section before the moment of activation photoelectric smoke detector (\(x<1\)), because they range relatively widely. Thus, criterion II is determined to be capable only of distinguishing kerosene, and only with signals measured at \(i=15^{\circ}\). As criterion 3 is applied, Figure 11 shows the ratio through the measured signal of light extinction (\(0^{\circ}\)) and light scattering (\(15^{\circ}\)-\(165^{\circ}\)) inside the LSC. The evaluation is based on the concept of SSA. Figure 11a shows the relationship between the signals for light  
Figure 10: Comparison of results according to criterion II for the combustibles inside the chamber. Figure 9: Example of insufficient results according to criterion I for the combustibles inside the chamber. extinction (0\({}^{\circ}\)) and light scattered at 15\({}^{\circ}\). The values for filter paper range from 2 to 7, and those for kerosene range from \(-\)2 to +2. As PU shares properties with both filter paper and kerosene, it exhibits no clear trend. As a result, ranges according to smoke color can be specified through post-processed data, except for cases in which there is almost no smoke. If the result is less than +2, smoke generated from filter paper (white smoke) is excluded, and if it exceeds +2, kerosene (black smoke) is excluded. Figure 11b shows the relationship between light extinguished (0\({}^{\circ}\)) and light scattered at 150\({}^{\circ}\). The values for smoke generated from filter paper range from 5 to 20, and those for the smoke particles of kerosene range from 0 to 5.