By Bob Dolph · November 26, 2015
Have you been to an ice cream or frozen yogurt shop lately? It’s not your grandmother’s ice cream parlor from days gone by. The kaleidoscope of flavors is designed to not only attract the customer to new trends but also fulfill their expectations anew.
Now that you are ready to go out and fill up on your favorite frozen confection, let’s see how all this relates to the many flavors of intrusion detection sensor technology.
One of the best resources for referencing intrusion detection products and applications is the 192-page Intrusion Sensor Application Notebook from Interlogix, a part of UTC Building & Industrial Systems. This free publication, having transferred ownership through the years from the original Sentrol, is a worthy addition to any security pro’s reference library. Security technology professionals are urged to download a copy here. Although this latest available version was published by GE in 2005, it remains one of the best collections of intrusion application examples.
It’s time to revisit a select few of the traditional detectors and methodologies that are still very much relevant today. Then we’ll move on to some of the noteworthy intrusion advancements.
Proven Technology Still Delivers Protection
Let’s first look at the tried and true traditional types of intrusion detection devices. Just as vanilla remains the No. 1 flavor among the masses, so goes the use of the all-time favorite alarm door and window contact. Today’s hermetically sealed contacts are very reliable — if installed correctly. Caution: recessed contacts forced into undersized holes and/or green wood can cause delicate glass-sensor enclosures to crack. This can only spell intermittent false alarm problems in the near future. Understanding magnet sensor hysteresis, alignment and end of line (EOL) supervision will also make for higher performance reliability.
The traditional sealed magnetic reed alarm contact has been reinvented by a company called Magnasphere. These alarm contacts use a metal casing and ball configuration, and do not have any glass that can be damaged. Because of the device’s nontraditional configuration, they have also been UL Listed for high security applications. Magnasphere also has a unique tilt sensor called the T1-AJ-JS that can be used in intrusion applications as well. Another version of the alarm contact is the tethered pull apart contact/cable, which can provide flexible intrusion detection. Some popular devices include the Magnapull Series from Interlogix.
Don’t forget about older but still worthy sensor technologies, such as window screens and pull traps. These devices are not only inexpensive but have proven themselves in areas that are environmentally harsh to electronics. A good example would be above ceiling crawl spaces in adjacent stores. One device is the WT-01 wire trip switch from George Risk Industries (GRI). Even an old-fashioned, breakable 24-26 gauge wire lacing circuit hidden in walls and doors can help in providing complete room protection.
Sensors That Detect Sound and Vibration
Now we’re going to move up a notch in the flavor spectrum to, say, butter pecan. For more high-level intrusion technology, this may include sensors that detect sound and vibration caused by an intruder. Penetrating even a concrete wall can be accomplished in short order during a burglary, so quick and early detection is imperative. Intelligent vibration intrusion sensors properly placed on the wall’s interior can provide good penetration detection. Examples include the ESA-350 shock sensor series from Tane Alarm Products or the SC100 Series seismic vibration sensors from Honeywell.
Sound detection can be achieved by such wares as acoustical glass-break devices (AGBD), which detect the combination of high frequencies from the breaking glass and the low frequencies of the glass flexing. Intrusion detection devices such as the Honeywell FG-730 FlexGuard Series should be carefully installed by the manufacturer’s instructions and tested with the Honeywell FG701 FlexGuard tester. Another AGBD with superior false alarm immunity is the Honeywell FG1025Z. This device electronically listens in opposite directions and compares sound coming from the glass with background sound from other directions.