FAQs for Photoelectric Smoke Detectors
What is a photoelectric smoke detector? How does it work?
A photoelectric smoke detector typically responds better to slow burning fires, fires that start as a small smolder. It consists of a light emitting diode and a light sensitive sensor located in a sensing chamber. As smoke enters the chamber and crosses the path of the light beam, the light is scattered by smoke particles, which deflect it toward the sensor and trigger an alarm.
What is an ionization smoke alarm?
Ionization smoke alarms are the most common type of smoke alarms, and are quicker to sense flames and fast moving fires. This type of alarm has a small amount of radioactive material between 2 electrically charged plates, which ionizes the air and causes current to flow between the plates. When smoke enters the chamber, it disrupts the flow of ions, thus reducing the flow of current and activating the alarm.
What’s the difference between ionization and photoelectric smoke alarms?
Compared to traditional ionization smoke alarms that are better at sensing small smoke particles from fast-burning fires, photoelectric smoke alarms can more quickly and accurately detect large smoke particles from smoldering fires. Photoelectric smoke alarms improve fire detection and reduce false alarms.
What type of smoke alarm should I buy?
Photoelectric and ionization and smoke alarms were developed to detect distinctly different yet potentially fatal fire types. Photoelectric smoke alarms are equipped with advanced sensing technology that can quickly and accurately detect smoldering fires and greatly reduce false alarms, so high-quality photoelectric smoke alarms will likely outperform traditional ionization alarms. However, no one can predict what type of fire might start in your home, so you will be best protected with an alarm that has both types of sensors. If your existing smoke alarms have ionization detectors, you can purchase photoelectric smoke alarms and install one next to each ionization unit.