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2. Installing the detector
2.1. Siting
Select a suitable position for the installation of both emitter and receiver, such that there
are no visible obstructions between them. Remember that the beam detector works on
the principle of reduction of light between the receiver and emitter. If there is any
possibility of an object remaining within the beam for a few seconds then the siting of the
detector is unsuitable.
For mounting either the emitter or receiver it is important to establish that the
mounting place such as the wall is solid and that the beam detector alignment
will be rigid. The wall may appear to be solid, but may be subject to twisting or
other changes when the temperature outside the building varies greatly during
one day, for instance on cold, frosty days. The installer must ensure that the
beam will not be subject to misalignment due to changes in the building itself.
The spacing and siting in specific types of locations is covered in section 9.
The beam detector must not be installed in the following locations :-
Where the ceiling height is greater than 40m
A roof top or place where open air circulates
Where the distance between top and bottom of the space is less than 0.5m
In locations where a large amount of dust, fine powder or water vapour is
present
In locations such as kitchens where smoke occurs normally
In locations which are exposed to extremely high temperatures
Where access to the detector is impossible for maintenance purposes
In locations which may be exposed to sunlight exceeding 5000 lux. It is
recommended that in locations where the beam detector may be surrounded
by glass, then the receiver should where possible be fitted so that it faces a
northerly direction (only relevant to countries in the northern hemisphere)
Where the rigid fixing of either the emitter or receiver is impossible
Where access to the beam detector to align and set is impossible
