Which detector type is specifically noted for detecting visible smoke from combustion products?

• A. Ionization Detector
• B. Photoelectric Detector
• C. Heat Detector
• D. Combined Alarm

Answer: (B)

Photoelectric detectors are built to sense smoke by detecting light scattering when smoke particles enter the chamber. The visible smoke produced by smoldering or slow-burning fires contains larger particles, which scatter the light more effectively and trigger the alarm sooner. This makes them especially associated with detecting visible smoke from combustion products. Ionization detectors respond more quickly to the tiny particles from fast flaming fires, heat detectors respond to temperature rises, and a combined alarm includes both sensing methods but the emphasis on visible smoke points to the photoelectric type.