Bosch FAS-420-TT Series - Detection in the Bypass

90 en | Installation of the pipe system Aspiration smoke detector LSN improved
2020.04 | 6.1 | F.01U.029.275 Operation guide Bosch Sicherheitssysteme GmbH
1
2
3
30°
Positioning the air sampling opening depending on air
speed
1 Aspiration pipe with air
sampling openings
2 Exhaust speed <0.5m/s
3 Exhaust speed >0.5m/s
6.4.2 Detection in the Bypass
Notice!
For detection in airflows ≥ 2m/s, additionally feed the exhaust from the FAS-420 back into
the airflow area. Cut the end of the air-return pipe at an angle of 45°.
1
2
3
4
b
1/2 b
Positioning the air-return pipe – example with an air-
conditioning duct (bypass)
1 Air-conditioning duct
2 Duct adapter
3 Aspiration
4 Air-return Pipe
b Width of air-conditioning duct
For details on connecting the air return, please see Air-return Pipe, page 92 .
For FAS-420 planning in these applications, see Planning for forced airflow, page 67 .
Refer to
– Air-return Pipe, page 92
– Planning for forced airflow, page 67