Bosch FAS‑420‑TP Series - Device Mounting; Measures for Reducing Operating Noise

18 en | Technical specifications Aspiration smoke detector LSN improved
2020.04 | 6.1 | F.01U.029.275 Operation guide Bosch Sicherheitssysteme GmbH
3.5.7 Device Mounting
1
2
FAS
-420 series
FAS-42 0
series
Mounting for FAS-420 series Aspirating Smoke Detector
1 Horizontal installation
2 Vertical installation
The MT-1 unit mounting is used if a direct wall installation is not possible, e.g. installation on
racks.
3.5.8 Measures for reducing operating noise
1
1
2
3
4
FAS-420 series
Absorption of the operating noises caused by airflows
1 Smoke aspiration pipe
2 Flexible hose
3 Fitting
4 Vibration absorbers
Vibration absorbers
The fans of the aspirating smoke detectors cause a noise level of approx.45dB(A). Mounting
the FAS-420 onto vibration absorbers can effectively reduce noise transmission through the
installation elements. This results in a reduction in the noise level from 1to 2dB(A).
Additional operating noises may be caused by vibrations on the pipe system, which are
generated by the air flowing through it. This can be remedied by inserting a corrugated hose
(approx.15cm long) between pipe system and aspirating smoke detector to create a flexible
transition.
In noise-sensitive areas, the sound level can also be reduced by installing a piece of plastic
pipe approximately 100mm long into the air outlet opening of the unit. This is done by
breaking out the pre-punched opening in the protective grille (e.g. using a small edge cutter).
All ‑SL variants are equipped with an extremely quiet fan that limits the noise level to
31dB(A). Thanks to the additional sound damper, fan noise can be reduced to 23dB(A); this
ensures that the detector is in accordance with DIN4109 for living and sleeping areas.