The purpose of the employee alarm system is to reduce the severity of workplace accidents and injuries by ensuring that alarm systems operate properly and procedures are in place to alert employees to workplace emergencies.
OSHA's employee alarm systems standard 29 CFR 1910.165 applies to all employers who use an alarm system to satisfy any OSHA standard that requires employers to provide an early warning for emergency action, or reaction time for employees to safely escape the work place, the immediate work area, or both.
The employee alarm system must provide warning for necessary emergency action as called for in the emergency action plan, or for reaction time for safe escape of employees from the workplace or the immediate work area, or both.
An employee alarm system can be any piece of equipment and/or device designed to inform employees an emergency exists or to signal the presence of a hazard requiring urgent attention.
National Fire Protection Association (NFPA) 72, National Fire Alarm Code, requires a fire alarm signal to be distinctive in sound from other signals and can not be used for any other purpose.
The employee alarm must be capable of being perceived above ambient noise or light levels by all employees in the affected portions of the workplace.
Tactile devices may be used to alert those employees who would not otherwise be able to recognize the audible or visual alarm.
The two most common types of alarms are audible and visual devices.
Temporal and voice signals are the most effective means. In the United States, fire alarm evacuation signals are required to use a standardized interrupted four count temporal pattern to avoid confusion with other signals using similar sounding appliances. This pattern for smoke alarms is named the Code-3 temporal pattern (often referred to as T3) and produces an interrupted four count (three half second pulses, followed by a one and one half second pause). CO (carbon monoxide) detectors are specified to use a similar pattern using four pulses of tone (often referred to as T4)(Wikipedia).
Audible notification devices such as horns, bells, or sirens are no longer recognized for new systems by NFPA 72. The National Fire Alarm Code only recognizes temporal signals or voice signals. For visual signals, only strobe lights are now recognized by NFPA 72 and the Americans with Disabilities Act (ADA).
The following bells, horns and sirens, are only permitted in existing systems.
Workplace Announcement System: Speakers can be used to play a live or recorded voice message. They are often ideally suited for large workplaces where phased or guided evacuations are needed.
Visual alarms use steady, flashing, or strobe lights to alert workers to an emergency situation in areas where noise levels are high, especially where ear protection must be worn and audible signals may not be heard or may be misunderstood. Visual signals also provide an effective way to alert workers with hearing loss about an emergency. Provide visible signals in restrooms, in other general and common use areas, and in hallways and lobbies.
Flashing/Steady Lights: These lights are well suited for areas where ambient noise makes audible signals difficult to hear. These types of lights come with different colored covers for increased attention and can be ordered with rotating or flashing lights.
Strobe Lights: Strobe lights use high intensity flash tubes that are ideally suited for areas where high ambient light levels make traditional rotating or flashing lights difficult to distinguish or where ambient noise makes audible signals difficult to hear. Strobe lights are recognized as the most effective means. Only strobe lights are now recognized by NFPA 72 and the Americans with Disabilities Act (ADA).
For alarm systems to provide adequate notification in the event of an emergency, all devices, components, combinations of devices or systems constructed and installed must meet OSHA requirements and be approved.
Steam whistles, air horns, strobe lights or similar lighting devices, or tactile devices meeting the requirements of the OSHA standard are considered to meet this requirement for approval.
Make sure your installed alarm systems are:
To get the most from an alarm system, follow these guidelines when selecting devices:
To make sure devices stay operable, follow these guidelines:
To ensure your alarm system provides adequate coverage, follow these guidelines when placing alarm devices:
Employee alarm systems are important life safety devices and must be maintained in an operating condition at all times except during repairs or maintenance.
Routine Test and Maintenance: Test the reliability and adequacy of non-supervised employee alarm systems every two months.
Employees must know what types of emergencies may occur and what course of action they must take. Make sure all your employees understand the function and elements of your emergency action plan, including types of potential emergencies, reporting procedures, alarm systems, evacuation plans, and shutdown procedures. Discuss any special hazards your workplace may have such as flammable materials, toxic chemicals, radioactive sources, and/or water-reactive substances. Your training should address the following 7 subjects:
When your employees know how to sound an alarm and/or notify emergency personnel at the first sign of an emergency, it may make the difference between life and death.