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

Dec. 1, 2007
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.

Note: Attach the wire to the magnetic contact and secure the magnetic contact before running the wire to the enclosure.

I was invited to the installation of a Detex EAX-3500 exit alarm onto a side exterior door of a building within a large facility.

The low voltage hard-wired Detex EAX-3500 Exit Alarm is designed for applications that require a wall mounted unit. The EAX-3500 is equipped with microprocessor based electronics, timed bypass, auto-rearm, tamper resistant metal enclosure and a patented mortise cylinder cam receiving assembly. The microprocessor based electronics have customizable settings that can be field-selectable to suit your needs. The cam assembly automatically adjusts for varying lengths mortise cylinder. The mortise cylinder must be equipped with a standard Yale cam to operate the mechanism. The mortise cylinder provides the reset function.

The wall-mounted exit alarm is powered using a 24 VAC transformer that charges the battery included with the exit alarm. Normally, this type of exit alarm provides a greater number of available options including the ability to monitor adjacent doors. The Detex EAX-3500 is designed so that the magnetic contact switch can be located up to 50 feet from the enclosure. This capability can help protect against tampering. In addition, a tamper switch is activated when the cover is opened without first disarming the unit.

The Detex EAX-3500 metal enclosure is approximately eight inches wide by eight inches tall by four inches deep, whose door is secured with a cam lock. To simplify operation, the by-pass instructions are printed onto the front and inside of the exit alarm.

Two screw slots and two screw holes can be used to mount the exit alarm. The EAX-3500 comes with eight mounting screws; four self-drilling and four sheet metal, and four plastic anchors for drywall installations.

NOTE: When mounting the exit alarm onto drywall, drill the anchor holes using 3/16” diameter drill bit. This way there is more material to secure the anchor to the drywall.

The timed bypass feature permits the exit alarm to be temporarily bypassed for a period of minutes, but never disarmed. The door can be opened and left open for a pre-set period of time. To activate the bypass, the tamper switch post must be pulled out to the activation position.

The surface-mounted EAX-3500 timed bypass can be set for five, 10, 20 or 40 minutes. The surface-mounted light bar indicates the time remaining.

Once the bypass feature is set, if the door is left open beyond the programmed time, the alarm will sound and must be reset using the key. If the door closes, prior to the bypass time expiring, the exit alarm will automatically re-arm, sounding the alarm if the door is opened without first disarming the unit.

This exit alarm is equipped with a Piezo horn alarm that produces approximately 100dB when an unauthorized individual opens the alarmed door. A 100dB alarm produces sound that can be heard from 60 feet in an ambient condition.

The EAX-3500 Exit Alarm comes with a peel & stick door sign. Because of company restrictions, the exit signs would be removed and company personnel would install the new door sign at a later date.

The Detex EAX-3500 Exit Alarms have a three-year warranty.

Detex Corporation has been manufacturing exit control security products for more than 40 years. For more information, contact your local locksmith wholesaler or Detex Corporation, 302 Detex Drive , New Braunfels , TX 78130 . Telephone: 830-629-2900. Fax: 830-620-6711. Web site: