Residential fires account for the majority of all fire fatalities. Fires occurring in the residential setting can be either smoldering or flaming types of fires. They can also begin slow smoldering and then rapidly progress to flames.
Manufacturers of smoke detectors now offer a combination of improved technologies so that residential homeowners can be better protected from fire. However, many older technologies are still being sold which provide a delayed response in certain fires and are prone to false alarms.
Research has demonstrated that photoelectric smoke detectors are more effective at warning people of smoke from smoldering fires than ionization smoke detectors. With earlier warning, people have more time to escape a burning structure.
Photoelectric smoke detectors contain a light source and a light-sensitive electric cell. Smoke entering the detector deflects light onto the light-sensitive electric cell, triggering the alarm. This type of smoke detector is also less susceptible to nuisance alarms. To prevent nuisance alarms, citizens often disable smoke detectors and place themselves, other residents in a home or building and fire fighters at great risk.
Ionization smoke detectors have a small amount of radioactive material, and establish a small electric current between two metal plates, which sound an alarm when disrupted by smoke entering the chamber. Studies have shown that this technology while useful in detecting flaming type fires has proven less sensitive to large particles given off during smoldering fires -- the kind of fires that occur at night when people are asleep.
It is the position of the North College Hill Fire Department that all homes be protected with a minimum of both photoelectric and ionization type smoke detectors with additional emphasis on placement of specific smoke detector technology in areas subject to false alarms. Since false alarms of smoke detectors can result in the removal of batteries, which in turn renders the smoke detector inoperative, it is our position that photoelectric technology placement be considered in areas commonly associated with false alarms (i.e. kitchens and bathroom areas).
The remaining portions of all homes should be protected, at a minimum, by smoke detectors utilizing both photoelectric and ionization technologies. This is best accomplished by utilizing a combination of smoke detectors. Since the type of fire cannot be predicted, utilization of both technologies within a single smoke detector provides maximum protection and the earliest possible warning for the occupants.
It is imperative for the above recommendations be followed in their entirety. When a choice must be made, photoelectric smoke detectors should be chosen over ionization smoke detectors.