Using the scattered light principle inherent in optical detectors, the EVC-DP Dual Optical Detector goes one step further and uses both IR and blue LEDs to provide a more accurate measurement of particles within the chamber. By calculating the ratio of these light sources, which operate at different wavelengths, the EVC-DP can determine the particle size and thus distinguish between smoke and non-combustion products such as steam and dust. This patented, award winning technology is unique to Nittan and provides an excellent solution to false alarms in areas prone to steam and dust, including hotels, hospitals and other areas of multiple occupancy.