How Smoke Detectors Work Not all fires are alike. Some are slow
burning and smoky, some are fast burning, producing high heat
but less smoke. Each type of fire requires an appropriate
technology. On this page: A metal heat detector is a device that
detects the heat from a fire and sounds an alarm or triggers a
water sprinkler system. Heat detectors do not detect smoke and
will not meet fire codes that require a smoke alarm. Smoke
Detectors and Alarms Smoke alarm technology detects smoke from a
fire and sounds an alarm. Several types of smoke alarm
technologies are available. Photoelectric sensor technology
relies on an electric current that produces a beam of light.
When the beam of light is interrupted, an alarm sounds.
Photoelectric sensors detect slow, smoldering, smoky fires more
quickly than other technologies. Photoelectric smoke detectors
contain a light source and a light-sensitive electric cell.
Smoke particles in the detector deflect the light onto the
photoelectric cell, thus generating a current a