Click image for larger version.  Name: Unknown Emergency.jpg  Views: 47  Size: 114.9 KB  ID: 6241

Earlier we were discussing emergency doors doing double duty for ventilation. I found an image showing an emergency door with a built-in fan. Presumably you open the door, swing the fan over the opening and turn it on. At the end of day, turn off the fan, swing it over, and close the emergency door. It's rare enough to find images of emergency doors and this is the first one I've seen with an integral fan.

Found at http://www.flickr.com/photos/chrispo...in/photostream apparently in New Haven, Connecticut. Unknown maker.