Smoke Alarms

Life Safety Facts

The smoke alarm is the most important and in many cases the only life safety device in your home
70% of fire fatalities occur in homes without working smoke alarms
Experts estimate that 1 in 3 homes have a smoke alarm that does not work

The two most common reasons smoke alarms do not work in homes

Disabling (taking the battery out or disconnecting) the smoke alarm to prevent it from making "annoying" sounds. Most battery-powered alarms "chirp" to alert you when their battery power is low. When you hear the warning, replace the batteries; don't disconnect them
Not replacing the smoke alarm every 10 years

Batteries should be replaced twice a year. Try to replace the battery in the spring and fall when you change your clock to daylight savings time. If you did not change the batteries in your smoke alarm yet, it is not too late, you can still do it today
More information about smoke alarm batteries

Ionization Smoke Alarm (PDF) - Ionization alarms contain radioactive material that ionizes the air, making an electrical path. When smoke enters, the smoke molecules attach themselves to the ions. The change in electric current flow triggers the alarm. The radioactive material is called americium. It's a radioactive metallic element produced by bombardment of plutonium with high energy neutrons. The amount of radiation is very small and not harmful
Photoelectric Smoke Alarm (PDF) - These alarms contain a light source (usually a bulb) and a photocell, which is activated by light. Light from the bulb reflects off the smoke particles and is directed towards the photocell. The photocell then is activated to trigger the alarm