Preventing Theft With The Detex EAX-3500 Wall Mount Exit Alarm

To combat theft while maintaining life safety, alarm-equipped exit devices sound when a non-authorized individual opens the door. Modern exit alarms still enable immediate egress through an emergency exit.

A common shoplifting technique is known as “grab and run.” A shoplifter enters a retail establishment, usually with known intention. The shoplifter goes to the intended target's location, “grabs” and proceeds quickly sometimes at a “run” towards the nearest store exit, usually a side or rear delivery door or emergency exit where there is the least number of people, especially store employees. The intention is to get away without being able to be identified. This is probably one of the reasons why high-ticket items like cigarettes and alcohol are normally placed at or near the front end of a market.

According to a number of reports, “pilferage” theft by non-employees accounts for a significant annual loss for retail businesses large and small. According to one report, small companies have reported losses of upwards of 20 percent.

Fire codes require that fire rated doors (emergency exits) provide unrestricted egress. This way in case of an emergency, people can safely exit a building using these doors without having prior knowledge. This means that a single motion, such as turning a level handle or pushing on an exit device bar, will unlock the door and permit it to be opened.

A person cannot legally lock or block a fire rated door. If a fire rated door is blocked or locked, an authority having jurisdiction (AHJ) can fine the occupant. If the violation is not corrected, the AHJ can revoke the occupancy permit, forcing the occupant to close and lock their doors until the problem is corrected.

To combat non-employee pilferage while maintaining life safety, exit alarms and alarmed exit devices were developed. The alarm-equipped exit devices are designed to sound when a non-authorized individual opens the door. The sound alerts employees that someone is opening the non-customer door. Modern exit alarms still enable immediate egress through an emergency exit.

The alarmed exit device is an exit device that also is an exit alarm. When the alarm mechanism is activated, depressing the bar or unlocking the outside trim activates the alarm, whereas an exit alarm sounds when the door is opened. Most exit alarms use some type of magnetic contact switch to control the operation. For this article we will discuss exit alarms, specifically the Detex EAX-3500, a surface wall mounted exit alarm also available with a flush mount kit.

The wall mount exit alarms normally use a magnetic contact to act as the switch mechanism, opening the closed-loop circuit when the door is opened. For our purposes, there are two types of magnetic contacts: surface and flush mount. For this installation, a Sentrol surface mount magnetic contact was used.

The magnetic contacts are comprised of two components. The wired switch contains two bimetallic metal strips that normally create an open loop contact. When placed against the second component, an encased magnet, the metal strips are drawn together, forming a closed loop, similar to a short circuit. This creates the closed loop circuit.

The two components are installed adjacent to each other, so the circuit is closed when the door is closed. As the door is opened, the door magnet moves away from the wired switch and the two metal strips open the circuit, sounding the alarm to notify that the door has been opened by a non-authorized individual. The Detex EAX-3500 is sold as a kit that includes the magnetic contacts, power source and cover lock, (mortise cylinder required and sold separate). The installer must supply the wiring to connect between power source and magnetic contacts. A rechargeable battery is included to act as a backup for when power to the building is lost for periods less than three days.

The magnetic contact is wired to the vertical terminal on the hinge side of the display board. Two wires mounted onto the magnetic contact are wired through the rear of the enclosure and to this terminal. When installing, be sure to leave a sufficient length of wire to accommodate opening the door.

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