The local consumer magazine in Washington DC says of glass breakage listening devices "A recent study by the Association of Central Monitoring Stations declared these devices unreliable".
I can't find a date on the article, so I checked the web site of the Central Station Alarm Association. I couldn't find anything there either. I have had a few local companies come by to assess my home and almost all have recommended them.
Are they reliable? Do they give lots of false alarms? Should I use them iin my home?
I don't know how long ago that study was performed. Acoustic glass break detectors have never been 100% reliable. They can and do add to the security of an installation when properly installed though.
Almost all of them will false if there's a heavy thunderstorm directly overhead. I used glass breaks (along with full perimeter magnetic contacts and interior motion detection) on most of my installations for many years with relatively few problems. That was in Connecticut. Now I live in Florida and I'd hesitate to use them here -- way too much lightning.
Everyone has his own preferences on makes and models. I've had good results with IntelliSense (Honeywell) glass breaks. When they first came out Sentrol's (GE Security) Shatterbox series were awful. They would false if a broom dropped in a neighbor's house. :^) I haven't used these but several friends who use them indicate the more recent ShatterPro series seem to have overcome the early problems. I sell both brands to DIYers online and have not had any returns in quite some time.
Glassbreak detectors are a device that need special attention both during the installation process and then again when/if there are any changes to the protected area. Changes in decor, furniture, window treatments, flooring, etc. will effect the sensitivity of the detector. What was good yesterday may not be good today after changes were made to the area. So after changes, the detector(s) will need to be checked for their sensitivity range. A detector that senses both frequency and vibration is recommended and one that has adjustable sensitivity capabilities is a must. Don't try to cover more area than what the detector is capable of at a mid range setting. There are range limitations and you should never take it out to the max. trying to save money. You won't be gaining anything except false alarms. The detector will be to sensitive, making it subject to false trips. Keep in mind that this device hears noise and feels vibrations, so location is important. There are simulating devices that the technician should be using when installing these devices to calibrate the sensitivity properly. Rattling keys or clapping hands is not the proper installation method. I have installed literally thousands of glassbreak detectors and have had good success with them. As with any power device, the panel battery can cause these devices to false if there is a black/brown out and the battery is not capable of supporting the power load on the system. Keep your battery reliable by changing every 3 years. To answer you question more directly, audios are fine and if installed and located properly should not be a false alarm problem. Hope this helps. Good luck.
"Andrew" wrote in message news: snipped-for-privacy@o13g2000cwo.googlegroups.com...
I have had four breakins where the glassbreaks activated properly. None that I am aware of where they did not.
Two were from vehicles that ran through the front of a building, and the other two were from a rock through the window.
That being said I have also had some false alarm problems. Usually in small spaces with a high degree of echo. ie.. all tile bathrooms etc. Usually switching out the glass break to one with adjustable sensitivity will reduce this problem.
I have had two odd circumstances that caused false alarms. One was a small barking dog. If it barked in one particular room of the house it would trigger the glassbreak in that room. It did not trigger the glass break in any other room. There was a very bad acoustic echoe in the room in question. The other odd one was in a store front. A slightly over sensitive glass break tripped when ever somebody knocked on the front glass. Not a sound volume or combination that would normally trigger the glassbreak. As it turns out they had a toy bird in a cage that chirped whenever there was a loud noise in the area. A loud smack on the glass would alert the glassbreak sensor and then the bird chirpig what trip it. I stood there on ladder staring at it until I found the cause.
One thing to consider is that there are some circumstances where a glassbreak may not operate when there is a broken window. One example is where they are installed and tested at near maximum range in a room where there are no or very light curtains, then later heavy drapes are installed. They also typically do not work reliably with small panes of glass.
In your home if you do not skimp on them they should work reliably with few to no false alarms. If you do not have them active when the house is occupied there should be no false alarms, but quite often people prefer the level of detection they get by having their glassbreaks active when they are at home. If you do simpley discipline yourself to call in any false alrms to your central station right away and know how to silence your alarm when it goes off.
On the subject of glass breaks, I had one do its job last night. :) It was an intellisense fg series. Ive also had them not do their job when they should have :( But thats why I back them up with motions
I still say the FG730 is the best they ever made... I've never had one false (even in Alberta, the lightning capital of the prairies)... Properly installed and adjusted (you must use the manufacturer's tester), the FG series of glass breaks are awesome...
Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.