Bosch DOW 1171 Operation Manual page 12

12 en | Installation/Configuration Notes
Construction
Thick, damp brick wall
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.
Figure 4.7: Calculation example for planning of RF fire detection system
The individual transmission paths (FS) can be calculated as follows:
–
–
–
–
–
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.
2016.04 | 6.0 | 4.998.120.885
DOW 1171
1
FK 100
2 = 4 m
SMF121
FS 1: Attenuation corresponding to distance + attenuation through reinforced concrete
ceiling
=> 40 dB + 30 dB = 70 dB
FS 2: Attenuation corresponding to distance
=> 35 dB
FS 3: Attenuation corresponding to distance + attenuation through concrete wall
=> 53 dB + 6 dB = 59 dB
FS 4: Attenuation corresponding to distance + attenuation through concrete wall
=> 57 dB + 6 dB = 63 dB
FS 5: Attenuation corresponding to distance + attenuation through reinforced concrete
ceiling + concrete wall
=> 67 dB + 30 dB + 6 dB = 103 dB
= 5 m
4
3 =
7,5 m
Operation Guide
Radio Frequency Fire Detection System
Attenuation
40 dB
= 15 m
5
10 m
=
DOW 1171
SMF121
Bosch Sicherheitssysteme GmbH
DOW 1171