Bosch DOW 1171, Operation Manual

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12 en | Installation/Configuration Notes Radio Frequency Fire Detection System
2016.04 | 6.0 | 4.998.120.885 Operation Guide Bosch Sicherheitssysteme GmbH
Construction Attenuation
Thick, damp brick wall 40 dB
Table 4.2: Additional attenuation due to construction elements on the transmission path
Calculation example
In the figure beneath, the FK 100 LSN Interface Module is installed under a reinforced
concrete ceiling (white), the dividing walls are made from concrete (gray). The RF detectors
are placed at different positions with and without a visual line to the RF interface module.
FK 100
DOW 1171
5 m 1
5
3
2
4
SMF121
SMF121
DOW 1171
DOW 1171
15 m
10 m
4 m
7,5 m
=
=
=
=
=
Figure 4.7: Calculation example for planning of RF fire detection system
The individual transmission paths (FS) can be calculated as follows:
–
FS 1: Attenuation corresponding to di attenuation through reinforced concrete
ceiling
=> 40 dB + 30 dB = 70 dB
– FS 2: Attenuation corresponding to distance
=> 35 dB
– FS 3: Attenuation corresponding to di attenuation through concrete wall
=> 53 dB + 6 dB = 59 dB
– FS 4: Attenuation corresponding to di attenuation through concrete wall
=> 57 dB + 6 dB = 63 dB
– FS 5: Attenuation corresponding to di attenuation through reinforced concrete
c concrete wall
=> 67 dB + 30 dB + 6 dB = 103 dB
The transmission paths 1 to 4 can be operated. In the case of transmission path 5, the
detectors are no longer reached, as the attenuation exceeds 90 dB.