Ionization detectors use a small amount of radioactive material to make the air within a sensing chamber conduct electricity. [Miniscule] smoke particles will enter the detector chamber and trigger the alarm. [Most of] these small particles are produced by flaming fire, resulting in the ionization detector to respond faster to flaming fires than photoelectric detectors.
Photoelectric detectors use a small light source which shines its light into a dark chamber not normally exposed to light. This dark chamber contains a photocell to detect light. When smoke particles enter the sensing chamber, light is reflected off of them and into the sensing chamber. This causes the alarm to trigger. This method needs bigger smoke particles than ionization detectors [and seems to work best] with smoldering fires.
Even though the average particle size changes considerably with temperature, fires usually produce a broad range of particle sizes. Therefore, both types of detectors will detect most fires. - Source: www.framinghamfire.org
“There is no practical discernable difference in the detection performance of these two technologies in their present form in most applications." (www.sbt.siemens.com quoting from the Canadian Property Management Magazine)
“WIRELESS" VERSUS "HARDWIRED”
A hard-wired smoke detector requires professional installation by an electrician or a fire alarm company. A wireless detector is normally AC powered; it’s simpler and doesn’t require professional installation.
“ELECTRIC" VERSUS "BATTERY-POWERED”
Battery-powered smoke detectors have a low-battery indicator; usually it will beep when it’s time to replace the battery. Some electric models have battery backup for the audible alarm, but not for the strobe light.
“WALL MOUNT” OR “CEILING MOUNT”?
The choice between ceiling mount or wall mount is personal and entirely yours! It could be for aesthetic reasons, whichever works best with your household or business setting. The Framingham Fire Department recommends that smoke detectors be installed on ceilings, based on the fact that “smoke rises”.
