Which type of smoke detector uses light scattering or obscuration for operation?

A photoelectric smoke detector operates using light scattering or obscuration. It contains a light source, typically a light-emitting diode (LED), and a light sensor. In the event of smoke entering the sensing chamber, the smoke particles scatter the light beam emitted by the LED. This scattering changes the amount of light that reaches the sensor, triggering the alarm when a certain level of obscuration is detected.

This type of detector is particularly effective at sensing larger smoke particles, which are often produced during smoldering fires. This characteristic makes photoelectric detectors advantageous in early smoke detection for certain fire scenarios, thereby enhancing safety and response time in residential and commercial settings.

In contrast, ionization smoke detectors operate based on radioactive material that ionizes air and detects changes in conductivity due to smoke particles, while thermal smoke detectors respond to changes in temperature rather than smoke directly. Multisensor smoke detectors combine multiple sensing technologies to provide a broad range of detection capabilities.