Dialing "911" is a common method for reporting emergencies if external emergency personnel are used at your workplace. Internal numbers may be used for reporting emergencies. If they are, they should be posted on, or near, each phone. Internal numbers sometimes are connected to intercom systems so that coded announcements may be made. In some cases, employees are requested to activate manual pull stations or other alarm systems. No matter what system is used, it is imperative that emergency situations be immediately reported. Fires and other emergency situations can reach dangerous levels in seconds and any delay in getting emergency responders to the scene can result in additional loss of life and property.

Once an emergency that requires a response from employees is reported, a system - typically an alarm system - must be in place to notify employees. Alarms must be distinctive and recognized by all employees as a signal to evacuate the work area or perform other actions identified in your emergency action plan. The alarm must be capable of being perceived above ambient noise and light levels. Sequences of horn blows or different types of alarms (bells, horns, etc.) can be used to signal different responses or actions from employees. Ideally, alarms will be able to be heard, seen, or otherwise perceived by everyone in the workplace including those who may be blind or deaf. Otherwise, floor wardens or others should be tasked with ensuring all employees are notified. You might want to consider providing an auxiliary power supply to your alarm system in the event of an electrical failure. Consider making available an emergency communications system, such as a public address system, for broadcasting emergency information to employees.

See also: OSHA's requirements for employee alarms.