US Patent 9525308 Emergency door release with backup power

The present disclosure provides an emergency door release operable to release or command-to-close a rolling emergency door from its uppermost, or open, position to its lowermost, or closed, position, in response to an emergency condition even when there is a loss of mains input power, while also avoiding releasing the door solely upon a loss of mains power. The emergency door release comprises an emergency detector for detecting an emergency condition, a microcontroller for closing/releasing the rolling door in response to the emergency condition, a backup power means for providing backup power to the microcontroller during a loss of mains power, and a door retention system for retaining the rolling door when powered, and releasing the door when power is removed from the door retention system.