Which type of detector is more responsive to smoke, ionization or photoelectric?

Photoelectric smoke detectors are generally more responsive to smoldering fires, which produce a larger amount of smoke and visible particles than flaming fires. These detectors work by utilizing a light source and a photocell; when smoke enters the chamber, it scatters the light beam, triggering the alarm. This makes photoelectric detectors particularly effective for detecting smoke from slow-burning, smoldering fires.

In contrast, ionization smoke detectors are more responsive to flaming fires that produce little smoke but have rapid combustion and heat. They use a small amount of radioactive material to ionize the air inside the detection chamber; when smoke enters, it disrupts this ionization process, triggering the alarm. Therefore, while ionization detectors are effective for fast-burning fires, they may be slower to respond to dense smoke from smoldering fires.

Considering this functionality, photoelectric detectors are generally regarded as the better option for detecting smoke, especially in residential settings where smoldering fires could pose a significant risk.