## 3 Results and Discussion  
### Primary Processing Scattering Light Distribution According to Smoke Particle Color  
Figure 3 shows the change in scattering intensity (\(I_{i}-I_{i}^{0}\)) to confirm the light scattering distribution according to the type of combustibles and the color of the smoke. A repeat calculation method was performed for all experiments to examine the differences, using the optical density (OD, m\({}^{-1}\)) of the smoke flowing into the LSC. Specifically, the method found the section in which the specific OD was measured for all experimental data, and calculated the average for each combustible. Figure 3(a) (the results for filter paper smoke,) confirms that a relatively large amount of scattering intensity was measured at 15\({}^{\circ}\) and 150\({}^{\circ}\). Figure 3(b) (the results for kerosene smoke,) shows that light intensity decreased or increased as the optical density increased at specific angles (15\({}^{\circ}\), 150\({}^{\circ}\), and 165\({}^{\circ}\)), but there is no consistent pattern at other angles. Figure 3(c) (the results for polyurethane smoke,) shows a tendency for OD and light intensity to increase proportionally only at angles of 15\({}^{\circ}\) and 150\({}^{\circ}\). Because of the characteristics of solid combustibles, not only is it difficult to control the smoke, but the amount of smoke generated is relatively small, making it difficult to perform an accurate analysis. Taken together, these results confirm the degree of change in the primary intensity when smoke particles are introduced into the LSC, and they provide numeric values for the difference in intensity according to the color of the smoke particles from the flammable materials. In addition, light scattering and extinction were simultaneously measured at 165\({}^{\circ}\) because of the LSC characteristics, and kerosene displayed relatively significant photoextinction. This implies that there is a limit to the ability to elucidate the optical properties of smoke particles generated from flammable materials inside the LSC. A photoelectric smoke detector used in a manner similar to this study does not consider the detailed signal of the interaction between the light source and the wall inside the chamber. \begin{table}
\begin{tabular}{c c} \hline
**No. ** & **Analysis Criterion** \\ \hline I & \(\left\{I_{i_{i},\,(i)}/I_{bs,\,(180^{\circ}-i)}\right\}/I_{ext,\,\,\,\,\,\,\, \,In order to confirm the absolute change rate (\(I_{i}/I_{i}^{0}\)) of the measured value, due to the limitation that the initial value was not measured uniformly in all light receiving units, the result of the dimensionless unit is shown in Figure 4 (excepted 105\({}^{\circ}\)). For all three fire sources, the scattered light was relatively strong at 150\({}^{\circ}\), then 15\({}^{\circ}\), then 45\({}^{\circ}\). In addition, it can be seen that the scattered light measurements are fine-grained, and the small figures inserted together are the results of the y-axis scale adjustment at a relative angle that is not clearly confirmed. Figure 4a shows the results for filter paper, and as the smoke is white, the light scattering signal is relatively large. In Figure 4b, the light absorption is found  
Figure 3: Comparison of experimental data about \(I_{i}-I_{i}^{0}\) at LSC on smoke particles. dominantly at 165\({}^{\circ}\) because of the characteristics of kerosene, which produces black smoke. In Figure 4c, a delay appears in the measurement time, because the PU generates a large amount of smoke after the pellet changes to a liquid after being sufficiently heated. As the color of the smoke particles generated from PU was gray-black, a decrease in the signal relative to the initial value of the light-receiving part was, again, observed at 165\({}^{\circ}\). Figure 5 shows the characteristics of the combustibles and their smoke particles to confirm the distribution of the scattered light for all angles inside the LSC.