Page 522 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 416

Smoke Detectors
Nearly all communities require some type of smoke detector. The most common are battery-powered
ionization detectors that recognize products of combustion even before flame is visible. Other types of
detectors recognize smoke or detect a rapid rise in temperature. If you have the opportunity,
recommend an AC-powered detector rather than a battery-powered unit. Surveys show that a high
percentage of battery-powered smoke detectors have a dead battery at any given time. For that reason,
many building codes require AC detectors, some with a battery backup.