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November 9, 2016

Burglar Alarms Part III — Key System Considerations

By John Bocker, NSSF Security Consultant Team Member

There are many options when it comes to installing a burglar alarm system, but as an FFL protecting firearms and doing everything you can to keep guns out of the hands of individuals not authorized to possess them, you should put significant planning into your protection and detection system. Choosing the correct detection hardware will not only deter burglary and support early detection of an intruder or vandal, it will hopefully provide some peace of mind when you secure and leave the premises each night. Let’s take a look at what your intrusion detection system (IDS) should include:

  • A premises control unit(PCU), alarm control panel (ACP), or simply a “panel” — Whatever you see it called, this is the “brain” of the system. It reads sensor inputs, tracks arm/disarm statuses and signals intrusions. Modern systems consist of one or more computer circuit boards inside a metal enclosure, along with a power supply. Your panel’s software should have extensive reporting capabilities regarding system activities.
  • Sensors — These are the devices that detect intrusions. Sensors may be placed at the perimeter of a protected area, within it or both. They detect intrusions via a variety of methods, such as doors and window openings or by monitoring unoccupied interiors for motion, sound, vibration or other disturbances.
  • Alerting devices — Most commonly these are bells, sirens strobe lights or a combination thereof. Alerting devices warn occupants of intrusion, potentially scare off burglars and alert law enforcement, neighbors and the nearby public of a security breech.
  • Keypads — Small devices, typically wall-mounted, that function as the human interface to the system. They typically feature indicator lights, panic buttons and a multi-character display in addition to standard alpha/numeric buttons.
  • Component interconnection — This may consist of wiring to the control unit or wireless links with power supplies.
  • Integrated security devices — Devices to detect intrusions, such as spotlights, motion-sensitive cameras and laser detectors.

Let’s take a closer look at some of these components and what you should look for when selecting them.

  • Door and window contact sensors — A very common type of two-piece sensor that operates with an electrically conductive reed switch that is either open or closed when under the influence of a magnetic field when it is in proximity to the second piece containing the magnet. When the magnet is moved away from the reed switch, as when opening a window or door, the reed switch either closes or opens (based on whether the switch is designed to be normally open or normally closed). This action, coupled with an electrical current (typically at 12-volt DC) allows an alarm control panel to detect a “fault” on that zone or circuit. These types of sensors are very common on windows, doors and hatches and are found either wired directly to an alarm control panel or in wireless door and window contacts as sub-components.
  • Passive infrared detectors — Passive infrared (PIR) motion detectors are some of the most common sensors installed in small business environments. The term “passive” refers to the fact that such sensors do not detect actual motion, rather sense heat given off by something or someone by detecting abrupt changes in temperature at a given point. For instance, when an intruder walks in front of the sensor, the temperature at that point will rise from room temperature to body temperature and then back again, triggering detection.PIR sensors may be designed to be wall- or ceiling-mounted and come in various fields of view from narrow “point” detectors to 360-degree fields. PIRs require a power supply in addition to the detection-signaling circuit. These devices are inexpensive and should be installed to detect intruders in all areas where a breach may occur.
  • Microwave detectors — This device emits microwaves from a transmitter and detect reflected microwaves or a reduction in beam intensity using a receiver. The transmitter and receiver are combined inside a single housing (monostatic) for indoor applications or in separate housings (bistatic) for outdoor applications. Microwave detectors respond to a Doppler shift in the frequency of a reflected energy by a phase shift, or by a sudden reduction of the level of a received energy. Either of these effects may indicate motion of an intruder.To reduce false alarms, microwave detectors are combined with a PRI—or “dualtec” alarm. Dualtecs are the recommended higher-sensitivity device to use for motion detection in facilities such as gun shops. Although slightly more expensive, these devices are extremely reliable and reduce the potential for false alarms.
  • Photoelectric beams — Photoelectric beam systems transmit visible or infrared light beams across an area where these beams may be obstructed. To improve the detection surface area, the beams are often employed in stacks of two or more, and especially if installed in stacks of three or more to create a fence-like barrier. Systems are available for both internal and external applications. These devices work extremely well when applied across long expanses in warehouse locations, across rooftops and in exterior fenced or secure “yard” areas.
  • Glass break detection — Glass break acoustic detectors are mounted in close proximity to glass panes and monitor for sound frequencies associated with glass breaking. These devices must be installed to manufacturer specifications to function properly. Seismic glass break detectors, generally referred to as “shock sensors,” are different from acoustic detectors in that they are installed directly on the glass pane. Breaking glass produces specific shock frequencies that travel through the glass (and often through glass frame and the surrounding walls and ceiling). Seismic glass break detectors “feel” these shock frequencies, generating an alarm condition.Note that window foil is a less-sophisticated, mostly outdated detection method that involves gluing a thin strip of conducting foil on the inside of the glass and putting low-power electric current through it. Breaking the glass is practically guaranteed to tear the foil and break the circuit. If you have this legacy technology installed, it is recommended that you upgrade and replace window foil with newer glass-break or motion sensors.
  • Driveway alarms — These can be tied into most security systems. They are designed to alert to unexpected visitors, intruders or deliveries arriving at the property. They come in magnetic and infrared motion sensing options and can be either hard-wired or wireless.
  • Vibration (shaker) or inertia sensors — These devices are mounted on barriers and are used primarily to detect an attack on the structure itself, such as an exterior wall or separating interior wall. The technology relies on an unstable mechanical configuration that forms part of the electrical circuit. When movement or vibration occurs, the unstable portion of the circuit moves and breaks the current flow, producing an alarm. The technology of the devices varies and can be sensitive to different levels of vibration. The vibration setting must be correctly selected for the specific sensor situation to detect things like wall penetration into a gun room or a car-ramming situation.

As I’ve stated before, you’ll need to employ a variety of these devices to ensure a layered defense against intrusion. Your choices are limited only by your imagination and budget. In the next installment, I’ll discuss wired versus wireless systems, the advantages of each, and hybrid solutions.

You may also be interested in: Alarm Testing the Pro Way


About the Author
John Bocker Headshot - NSSF Security Consultant Team MemberJohn Bocker is an NSSF Security Consultant Team Member and the Managing Director at JB Group, LLC, based in Denver, Colorado. JB Group is a business security and integrity strategy consultant organization specializing in maximizing profitability, risk management, employee integrity, operational controls and driving success! Visit or call (720) 514-0609 for more information.

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