## 3 Results and Discussion
### Primary Processing Scattering Light Distribution According to Smoke Particle Color
As mentioned above, this analysis was performed to assess the theory that forward scattering occurs mainly when the smoke particle size is similar to or larger than the wavelength of light. Specifically, the light-distribution scattering ratio (by combustible) is applied to total angles inside the LSC using the post-processed OD of dimensionless. In each plot, the angle axis is divided by 360\({}^{\circ}\), and represents the angular position of the photocell installed in the LSC. In addition, and the radial axis is scaled according to the results for the respective combustibles. Figure 4: Comparison of experimental data on \(I_{i}/I_{i}^{0}\), measured at LSC on smoke particles. The results confirm that filter paper (Figure 5a) has high forward scattering relative to kerosene (Figure 5b) and PU (Figure 5c). This finding is predictable based on Mie scattering theory. In addition, the larger the particle size, the greater the diffraction, and based on the report [35] that forward scattering tends to increase and side scattering tends to decrease as total external reflection decreases, it can be inferred that the smoke particles generated from filter paper are relatively large. Specifically, for the combustibles used in this study, the smoke particle size can be analyzed as a ratio of the measured light scattering distribution, and as shown in Figure 5, the magnitude of forward scattering is greater for filter paper than for kerosene or PU. By comparing of the results for kerosene and PU, kerosene is expected to have a smaller particle size, as it displayed side scattering at all angles. However, for light scattering characteristics, wavelength, and particle size, scattering angle, density, shape, and optical material constant (complex refractive index and absorption coefficient) should be considered [36]. In addition, it is difficult to find a clear reason for the agglomerate characteristics of smoke particles generated in a fire, due to their being complex phenomena. Post-Processing: Light Scattering Distribution According to Smoke Particle Color, with Criteria Applied  
The purpose of this study was to perform a direct comparison between the chamber of a photoelectric smoke detector in actual use in South Korea and the LSC, in terms of the signal inside the chamber representing the light scattering characteristics according to the  
Figure 5: The difference in the distribution of scattering intensity from smoke particles of combustibles. color of the smoke particles. To examine the light scattering characteristics inside the smoke detector chamber, it is necessary to consider the concentration of smoke at the moment of activation, because the operating characteristics change according to the color of the smoke generated from the combustibles. To accomplish this, it is necessary to install a photoelectric smoke detector in the same location where the airflow enters the LSC, but this is difficult because of the design of the device. In addition, as the flow at the location of the test section (Figure 1a) was low-speed, the average velocity of the cross-sectional flow entering the interior of the detector changed irregularly. To overcome this limitation in the future, we intend to apply the information derived in previous studies [9] through the use of a fire detector emulator (FDE). Here, the scattering signal measured in the LSC was evaluated together with the information appropriate for identifying the optical characteristics by using the information measured by the fire detector evaluation device, to which the test method was applied through the FDE. The signal measured at 0\({}^{\circ}\) inside the LSC for smoke generated by the combustibles is shown in Figure 6, in the form of OD over time as assessed using the light extinction method. The OD at the moment of detector activation according to the color of the smoke generated by the combustible material was presented for Company J in a previous study [9].