Portland, Ore. Currently, more than 90 percent of fire alarms are false, which leads to a laxness in response so severe that fire alarms in residential neighborhoods often go unheeded, according to the European Union's Information Society. When the number of false alarms reaches 99 percent, as it does in some applications, such as alarms in airplanes, even professionals who must respond to those alarms have a tendency to treat them as nonemergencies.
Now the EU's Information Society is doing something about it. It plans to launch a false-alarm-free fire detection system for 2006.
The project, dubbed the Intelligent Modular Multi-Sensor Networked False Alarm Free Fire Detection System (http://imos.fhnon.de), has just released test results that indicate the commercial version of its fire alarm, based on a prototype called IMOS, will virtually eliminate false alarms.
Two recent tests one in a smoking lounge and the other in a busy, dusty loading dock both performed flawlessly, according to the IMOS partners.
The IMOS prototype was the joint development effort of a nine-member cooperative spanning industry and academia in England, France, Germany, Greece, Hungary, Italy and Switzerland.
Many manufacturers are currently gearing up to demonstrate commercial alarms based on the IMOS technology at the Security 2006 exhibition, to be held in Essen, Germany, next October.
The key to the false-alarm fire detection system is its smart approach. The reason that false alarms on airplanes reach 99 percent, according to the IMOS partners, is that when the temperature drops suddenly in the cargo compartment after liftoff, humidity in the air condenses onto detectors. The fire alarms are indeed sensing particulate matter when they issue a false alarm but it's just moisture, not smoke.
Look, then sniff
To remedy that, the IMOS technique uses a look-and-sniff approach.
An optical multisensor first determines if smoke is in the air, or just humidity. Then a laser scanner looks to see if there is particulate matter in the air. The detector portion of the electronics gets the go-ahead to sniff only if the laser scans smoke, thereby preventing the alarm from sounding when only condensed humidity is present.
In phase two, a second multigas-sensor system measures CO, CO2, NO, unburned hydrocarbons and alkaloids to determine whether the smoke is just from cigarettes or whether it comes from any of a variety of burnable materials that warrant an alarm.
By using a conductive polymer, the IMOS design can detect the difference between cigarettes, wood, cotton, paper and plastic. When particulate matter falls on the conductive polymer, its resistance changes in one of five bands, each tuned to a specific substance, then automatically resets after the smoke has cleared.
The false-alarm system is also wired into the Internet, enabling remote servicing and the downloading of updated software to its microchip.