This will be essential, especially during a drill or emergency, and it could prove to be a potential lifesaver. The sign is simple but effective and it will catch people's eye. It will be extremely useful in a time of crisis and it would even continue to glow if the lights go out as it is Jalite AAA photoluminescent. 

Fixing requires anything as simple as sticky pads, 'No-nails' type adhesive or double-sided tape.