Re: Window Foil

["Roland Moore" <nospam@xxxxxxxxxx>]

> Do you have any personal knowledge of a case where >there was an otherwise
properly armed alarm system >with glass break detectors where the GBD failed
to go off when the intruder broke in?

Yes. That can happen when a very small section of the glass is actually
broken, along a single line for example, instead of being shattered..

"Beachcomber" <invalid@xxxxxxxxxxxx> wrote in message
news:476b566b.14191593@xxxxxxxxxxxxxxxxxxx
>
> >It depends on which detectors you're using.  Some detectors
> >(IntelliSense, for example) are designed to detect the high frequency
> >cracking of the glass plus the low frequency pulse caused by striking
> >the glass.  The low frequency sound depends on the glass being part
> >of the perimeter of the space, like the skin on a drum.  These are
> >tested by thumping the glass, which in turn triggers the tester to
> >emit a sound similar to glass shattering.
> >
>
> A questions for the pros about glass break detectors from an old foil
> installer (who did a lot of drug and liquor stores... back in the
> 70's).
>
> Do you have any personal knowledge of a case where there was an
> otherwise properly armed alarm system with glass break detectors where
> the GBD failed to go off when the intruder broke in?   It would seem
> to me that that would be the worst case scenario.  I know that some of
> the best of them would go off during a thunderstorm, but that could
> happen to the foil window systems too.
>
> A basic loop alarm seems so simple, but plunger contacts can stick,
> foil can partially break, motion detectors can trip from pets and air
> turbulance, magnetic reed contacts can fuse together.
>
> Will the so called "Swingers" always be with us, or are there new
> developments in technology to minimize false alarms.
>
> Beachcomber
>
>
>
>
>