NFPA defines this as “a tool that detects visible or invisible particles of combustion.” The Ontario Fire Code defines smoke detectors as “a fire detector built to run when the concentration of airborne combustion products and solutions exceeds a predetermined amount.” The information on this Internet site is for informational http://fire-alarm-systems57789.aboutyoublog.com/13945267/the-definitive-guide-to-fire-alarm-systems