Most fire victims succumb to smoke--not to fire. Carbon monoxide from a fire can render a person unconscious after only a short period of time.
However, if you have one or more working smoke detectors  in the home, you double your chances of surviving a fire. Smoldering fires caused by discarded smoking materials  (the leading cause of U.S. fire deaths) and other sources are discovered quickly by smoke detectors. Since many of these fires occur at night, while people are asleep, the loud, piercing alert siren from the alarm alerts residents in time to escape--alive.