e1276e
17
Siemens Building T
echnologies
Cerberus Division
09.2000
4
Planning
4.1
General project engineering principles
The linear smoke detector DLO1191 is due to its detection principle and its large monitor-
ing surface for certain applications an attractive detector.
If local national regulations exist concerning application, have this priority!
4.2
Operating conditions
The distance between DLO1191 and reflector must be between 5m and 100m.
There must be a permanent, clear line of vision between detector and reflector.
The monitoring IR beam may not be interrupted by moving articles, e.g. overhead
cranes, ladders, transportable articles, spiders’ webs etc.
Turbidity of visibility caused by operations-related dust, steam or smoke develop-
ment can impair the system.
The mounting place of the detector must be statically absolutely stable, since the allow-
able deviation of the monitoring beam amounts to max 0,43
°
(see section 3.2).
Concrete and brick walls mostly fulfill these characteristics.
Pure wood and steel constructions are usually unsuitable, there temperature and hu-
midity variations, wind or snow pressure influence such constructions.
The monitoring beam must have free view at least 30cm on all sides, so that no un-
wanted reflections develop.
Frontal incidence of sunlight, light from halogen lamps, etc. on the DLO1191 should be
avoided if possible (to high temperature).
For the service staff the detector must be at any time well accessible.
Cleaning and adjusting works are badly executable on ladders. Suitable equipment
for this purpose includes fixed catwalks, platforms, ”Skyworker” etc.
The alarm activation of the DLO is based on the light attenuation caused by smoke (ex-
tinction). The accumulation of smoke in a fire is adequately dense usually only in the
”smoke plume”, in order to produce sufficient extinction for alarm activation.
For this reason always mount the DLO1191 in the vicinity of the ceiling (see Fig. 21 for
distances). It must not be too close to or too far from the ceiling.
For very high rooms we recommend to arrange additional DLO1191 on different lev-
els (see section 4.6.3) and/or additionally to install flame detectors.
If careful attention is not given to these points, the linear smoke detector system
cannot function correctly and sometimes later leads to insoluble problems with
unwanted activation of fault and alarm signals.
