Entrance and exit signs are often required by local safety codes in public places like restaurants and office buildings. Use entrance and exit signs near doors that are not already clearly marked, as well as stairways, warehouses or office buildings which may require extra identification to inform occupants and help them find their way in or out. The National Fire Protection Association is behind most of the requirements for entrance and exit wall signage. This organization provides instructions for building managers and owners to provide the correct information for building occupants. For instance, exit signs are required by all main front door exits, except when the door is made of glass and obviously an exit to the outside. Exit signs usually need to clearly state the location of exits whether they are stairway exits, passageways or signs pointing out the direction to the exit. By the same token, some signs display “No Admittance” instructions, denying access and communicating that this door does not provide an exit.