Photoelectric smoke detectors are some of the most popular types of detectors found in homes and offices. Unlike ionization technology, smoke alarms that employ photoelectric sensors detect fires that start after an extended amount of smoldering. It uses a source of light directed into a sensing compartment at an angle opposite the sensor. As smoke enters the compartment, the light is reflected back to the sensing comaprtment thus triggering the alarm.
Photoelectric smoke detectors are more more friendly to the environment versus their ionizing counterparts. They do not contain any radioactive materials so disposal is easy. Plus, photoelectric models are recommended by fire safety experts because they detect the types of fires that end up taking more lives statistically.
Below is an excerpt of an article why installing a photoelectric smoke detector is a far better choice than an ionization model.
Professional Fire Fighters of Vermont president Matt Vinci is also thrilled that the resolution passed. “It’s an issue that firefighters throughout the United States, Canada, and the world need to understand,” says Vinci, whose organization fought for state legislation mandating photoelectric technology following a fatal 2005 Barre, Vermont fire that killed a mother and four children after their ionization detector failed to sound an alert.
In May, Vermont Governor James Douglas signed that legislation, and at the recent IAFF convention he praised firefighters for taking a stand on photoelectric detectors. Massachusetts passed similar legislation this year, and Tennessee is currently considering laws enforcing photoelectric-only technology in new construction.
What’s wrong with ionization detectors? The IAFF resolution cites the 3,000 fire-related deaths that occur in this country and Canada each year, and states that in 30 percent of those fatal house fires, a smoke detector activates. Ionization detectors, the resolution states, “may not operate in time to alert occupants early enough to escape from smoldering fires.”
In another 20 percent of fatal fires, the detector has been disabled. According to one Alaskan study, ionization detectors are up to eight times as likely to be disabled as photoelectric detectors because of their propensity for false alarms.
As explained in two recent Hook cover stories, ionization detectors don’t detect the larger particles released by a smoldering fire, which is the type most likely to kill people when they’re sleeping. In various smoke detector tests– including one conducted by the Hook in June– ionization detectors didn’t trigger at all until a smoldering fire had erupted into flames.
By that time, residents in a burning structure could have become incapacitated by the various poisons released by a smoldering fire, including carbon monoxide and even cyanide. Photoelectric detectors, on the other hand, detect both types of fires, although they may react 30 seconds slower than ionizations in a flaming fire.
Fleming argues they still provide enough time to escape in either fire scenario, and he points out that they’re also less prone to false alarms.