Re: Reliability of glass breakage listening devices

["Bob La Londe" <usenet@xxxxxxxxxxxxxxxxx>]

"Andrew" <asrichman@xxxxxxxxx> wrote in message
news:1136404492.450925.16240@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> 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?
>
> Thanks,
>
> Andrew


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.
--
Bob La Londe
http://www.YumaBassMan.com