Siting Of Optical Beam Detectors

[lucky]

I knew the Kurnal would be okay.....Face masks on,check the return valve,check pressure,deep breath were going in.........

[Rich]

Just a comment.  I attended an afa on a couple of occasions at a commercial premises just after heavy snowfall.  It turns out that beam detectors were installed very close to the ceiling and the weight of the snow interfered with the beam thus actuating the alarm.  Ho ho ho!!

[Wiz]

Just a comment.  I attended an afa on a couple of occasions at a commercial premises just after heavy snowfall.  It turns out that beam detectors were installed very close to the ceiling and the weight of the snow interfered with the beam thus actuating the alarm.  Ho ho ho!!

Very interesting Rich. At first I thought maybe the ceiling must have sagged, but I suspect that the weight of the snow on the roof caused structural stresses everywhere including the wall(s) the detector was mounted upon. It is very important to fix optical smoke beam detectors to a solid surface, because the slightest structural movement can put them out of alignment. This is what probably happened at that site.

[Graeme]

maybe there was no roof and the snow flakes caused obscuration.

[Wiz]

maybe there was no roof and the snow flakes caused obscuration.

yes, good point. Maybe BS should include a 'catch-all' recommendation such as 'Automatic Detectors should not be installed in areas where there is no ceiling or any other circumstances where the protected area is open to the elements.'

[Martin Burford]

More fool the client/occupier for spending his cash un necessarily!
Congueror

[Graeme]

how do you mean-on a beamset?

[Rich]

Wiz,

Your first though was correct, heavy snowfall on the roof (yes there was one!!) caused it to sag sufficiently to actuate the beam.