10
Op ti cal Beam Smoke Detector
re tur ned si gnal from the glass/po li shed sur fa ces. The re flec ted si gnal from
the prism will be re tur ned to the de tec tor in the nor mal way.
4. In stal la tion.
Pre-in stal la tion at Gro und Le vel.
Con firm that all parts have been sup plied as listed in the parts list . See page
14.
Se lect the re quired alarm thresh old us ing switches 3 and 4 (See fig. 12 pag
16 for switch con fig u ra tion set tings). The fac tory de fault set ting is 35% this
should be ad e quate for most en vi ron ments, if the De tec tor is to be in stalled
into an ex cep tion ally dirty en vi ron ment change the thresh old to 50% .
There fore, with a roof pitch of 20 de grees the lat eral cov er age can be in -
creased from 7.5 metres ei ther side of the beam to 9 metres ei ther side of
the beam, but only for the beam po si tioned in the apex. All other cal cu la tions
re main the same.
3.3 De tec tor Po si tion ing In Atrium.
If the de tec tor is to be pla ced in a atrium, or near glass/po li shed sur fa ces,
the prism(s) sho uld be of fset from the cen tral line of sight (ap pro xi ma tely
300 mm), and an gled back to the beam de tec tor (See Fig. 6).This can be eit -
her on the ver ti cal or ho ri zon tal axis. This will re du ce the amo unt of spu rio us
FIG. 3
10
20
30
40
50
60
70
80
90
100
2
4
6
8
M
in
im
u
m
d
is
ta
n
c
e
b
e
tw
e
e
n
D
e
te
c
to
rs
(
m
)
Distance between Detector and Reflector (m)
10
12
14
16
0
10
0
5
FIG. 2
De tec tor spa cing.
FIG. 4
Detector must be positioned in roof apex
Roof can be defined as flat
FIG. 5
Li mit to when a Fi re ray must be po si tio ned in roof apex
