What are the two common types of smoke detectors?

Ionization and photoelectric smoke detectors are the two most common types of smoke detectors used in residential and commercial settings due to their distinct methods of detecting smoke.

Ionization smoke detectors contain a small amount of radioactive material that ionizes the air within a sensing chamber. When smoke enters this chamber, it disrupts the ionization process, triggering the alarm. This type of detector is particularly effective at sensing fast, flaming fires that produce little smoke.

Photoelectric smoke detectors, on the other hand, use a light source and a light-sensitive sensor. In clear air, the light beam passes directly from the source to the sensor; however, when smoke enters the chamber, it scatters the light, prompting the alarm to sound. This type is usually more effective for detecting smoldering fires, which produce a larger amount of smoke.

Together, these two technologies provide comprehensive coverage for different types of fire scenarios, ensuring better safety measures. Other options like optical and thermal, laser and heat, or chemical and electrical do not represent standard smoke detector technologies.