Identification method of fire smoke and nuisance aerosols in aircraft cargo compartment based on dual wavelength scattered light intensity

Abstract

The aircraft cargo compartment photoelectric smoke detector’s high false alarm rate is a serious threat to flight safety. Common nuisance aerosols that cause false alarms include dust, water vapor, and water mist particles. The light scattering characteristics differ between nuisance aerosols and smoke particles, which can be used to distinguish particle types to reduce the false alarm rate. For this experiment, we chose standard fire smoke particles, test dust particles, water vapor and water mist particles in accordance with the aerospace standard (SAE AS 8036A) as well as other standards like EN 54 and ISO12103-1. For numerical analysis, the scattering characteristics of fire smoke and nuisance aerosols under various wavelength incident light sources were calculated using Mieplot and Discrete Dipole Approximation (DDA). Under 460 and 940 nm light sources, measurements of the scattering light intensity of fire smoke and nuisance aerosols were done at different angles. The results showed that we could distinguish fire smoke from nuisance aerosols based on the ratio of the dual light sources’ scattering light intensity at a scattering angle of 30°. This method can effectively reduce the photoelectric smoke detector’s false alarm rate and better distinguish between fire smoke and nuisance aerosols in the aircraft cargo compartment.