What happens to automatic doors when a fire alarm is activated?

Automatic door systems and the fire alarm systems are linked together. Automatic doors are held open by strong magnetic type devices, that are activated(turned on) during normal activity. When the alarm is activated, the devices are shut off and the doors close. These doors are programmed to close in an effort to keep smoke and flames from spreading too far(these doors are usually strongly fire resistant.) Once the alarm is shut off/reset, the devices will be activated again and will remain open once somebody opens the doors back up.

Another type of "automatic door" is a fire door that slams shut (springs, counterbalances, gravity, etc) when the heat-sensitive link melts, or when a fire alarm is activated. These heavy doors are NOT intended to be opened during a fire for means of escape, so there must be other doors accessible for people to escape the area safely.