Dual sensor smoke alarms are smoke alarms which use two different detection methods for identifying fires. Many fire safety organizations recommend the installation of dual sensor smoke alarms because they cover a broad range of fires, making them much safer than single sensor alarms. As with any smoke or fire alarm, you should check your smoke detectors and replace their batteries at least twice a year. Many people like to do this when the time changes, as this biannual event already requires people to change their clocks and adjust other timed household devices.
The innards of a dual sensor smoke alarm include a photoelectric sensor and an ionization sensor. Photoelectric sensors are very good at detecting slow, smoldering fires like fires which start in mattresses, couches, carpeting, and drapes. An ionization sensor can detect a sudden burst of flame like a grease fire. The combined sensors work together to alert people to smoky conditions and fires.
The photoelectric smoke alarms in dual sensor smoke alarms use beams of light to detect smoke and fires. Under normal conditions, a light emitting diode creates a stream of light which can be read by the smoke alarm's sensor. In smoky conditions, when particles begin to obscure the beam, the sensor emits a signal to indicate that the beam of light has been disrupted, indicating smoky conditions or large amounts of particulates in the air.
Ionization smoke alarms in dual sensor smoke alarms use a small amount of radioactive material to create a conductive chamber. When the conductivity level of the chamber changes, as will happen when smoke fills the air, the smoke alarm is triggered. Because dual sensor smoke alarms do contain small amounts of radioactive material, consumers should handle them carefully and they should avoid opening up the smoke alarm, if possible. A dual sensor or ionization smoke alarm should also be properly disposed of, ideally in a waste center which handles hazardous materials.
When installing dual sensor smoke alarms, try to install one alarm in every bedroom, to ensure that sleepers will be awakened in the event of a fire. Smoke alarms should also be installed on every floor of a structure, and you may want to avoid keeping a smoke alarm too close to the kitchen, to avoid nuisance alarms which can be triggered by burn-happy cooks. It is also a good idea to keep working and fully charged fire extinguishers on every floor, and you may want to consider installing safety lighting which will work in the event of a fire to ensure that the occupants of a structure can get out easily.