Warning, emergency and maintenance LED signs

An alert sign has to be readable by someone who is not looking for it. That means one instruction, no decoration, and no attempt at brand voice. WET FLOOR. LIFT OUT OF SERVICE. FIRE DOOR — KEEP CLEAR.

Name the hazard and the action. “CAUTION” on its own tells nobody what to do; “CAUTION — STEP DOWN” does. If there is a safe route past the problem, the sign is the right place to say where it is.

The rule that matters most is turning it off. A warning that stays up after the spill is cleared teaches everyone who works there to ignore the screen, and the next warning is the one they will walk past. Maintenance notices have the same problem in slower motion: put the return date in the text so the sign expires in the reader's head even if nobody gets to it.