OSHA states per 1910.36(d)(1) that employees must be able to open an exit route door from the inside at all times without keys, tools, or special knowledge. A device such as a panic bar that locks only from the outside is permitted on exit discharge doors. (Note that an exit discharge means the part of the exit route that leads directly outside or to a street, walkway, refuge area, public way, or open space with access to the outside.)
Also, under a March 12, 1981 letter of Interpretation, OSHA adds that the use of an electronic device that must be pressed before the panic bar can be activated violates the intent of 1910.36(d)(1) and (e). Employers utilizing such a system can be cited. The agency explains that employees trying to evacuate a smoke-filled room may not be able to locate the electronic device and would be trapped at the exit door. The letter goes on to say that depression of the panic bar must open the exit without any prior action. In addition, relays that signal a security monitor of the occurrence and do not inhibit exiting are permitted.
Depending on local fire and electrical codes, there could be additional requirements or restrictions for any panic hardware installed in certain types of rooms.