Bosch FAS-420-TP2 - Page 51

Aspiration smoke detector LSN improved Planning | en 51
Bosch Sicherheitssysteme GmbH Operation guide 2020.04 | 6.1 | F.01U.029.275
Double U-pipe Max. distance FAS-420 – last T-fitting 20m
Max. branch length
– With low fan voltage
– With high fan voltage
30m
40m
Max. overall pipe length per pipe system (Ø 25mm)
– With low fan voltage
– With high fan voltage
110m
140m
Min. distance between 2 air sampling openings 4m
Max. distance between 2 air sampling openings 12m
Max. number of air sampling openings (n) per pipe system 12
M-pipe Air sampling opening Number of air sampling openings
3 6 9 12
Ø air sampling
opening in mm
a
A 4.4 3.4 3.0 2.5
B - 3.6 3.0 2.5
C - - 3.2 3.2
D - - - 3.2
a
Punch diameter of the aspiration reducing film sheet
M-pipe system activation thresholds per pipe system
Activation
thresholds
Number of openings 3 6 9 12
1 obstructed opening III I — —
2 obstructed openings 0 II — —
3 obstructed openings 0 III I —
4 obstructed openings 0 0 II I
5 obstructed openings 0 0 0 II
6 obstructed openings 0 0 0 III
7 obstructed openings 0 0 0 0
… will be recognized by the setting level x
— not possible, 0 not practical
Example
If 3 of a total of 9air sampling openings are found to be obstructed, the switch for setting the
airflow monitoring should be set to level I.
Notice!
When planning in accordance with EN 54‑20 or ISO 7240-20 , level I or II must always be set
for airflow monitoring.