Q: Is there a code that states every mechanical room needs an ‘Exit’ sign? I am being pressed to do so and I understand if the exit is obvious you don’t need a sign.
A: No… there is not. But section 188.8.131.52.1 of the 2012 LSC says access to exits shall be marked by approved signs in all cases where the exit or the way to reach the exit is not readily apparent to the occupants. So, one way this is interpreted, if you’re standing inside the mechanical room and the entrance door to the mechanical room (which also is an exit access) is not readily apparent, then you will need ‘Exit’ signs.
This is actually a very simple test that a surveyor can do while touring your facility… If the surveyor cannot see the entrance door when he/she stands anywhere in the mechanical room, then that is a clear indication the room needs to have the way to reach the exit marked. But if you can always see the entrance door, then one can say the way to reach the exit is readily apparent.
It is recommended that you use the internally illuminated ‘Exit’ signs connected to EM power, rather than trying to get by with externally illuminated signs.