What is a distinguishing feature of a photoelectric smoke detector?

A distinguishing feature of a photoelectric smoke detector is that it detects smoke using light. This type of detector operates based on the principle that smoke particles scatter light, typically emitted from a light source such as an LED, within the sensing chamber. When smoke enters the chamber, it disrupts the light beam, triggering the alarm.

Photoelectric detectors are particularly effective at detecting smoldering fires, which produce a lot of smoke without immediate flames. This contrasts with ionization smoke detectors, which utilize radioactive material to detect changes in ionization caused by smoke and are generally more responsive to fast flaming fires.

Regular manual testing, while important for all smoke detectors, is not a unique feature of photoelectric systems. Instead, it is a standard practice applicable to all fire alarm systems to ensure they are operational. Therefore, the use of light for smoke detection is what sets photoelectric smoke detectors apart from other types.