The Door Unlocked In Working Hours 5137 Sign will advise people that they are to keep a door, or perhaps something else, unlocked during working hours. This may well be necessary for reasons of safety.
If this rule must be enforced, prominently display enough of these signs, within the appropriate area, so that nobody will be able to miss this requirement. The sign will glow in the dark as it is AAA photoluminescent.
Fixing requires anything as simple as sticky pads, 'No-nails' type adhesive or double-sided tape.