Device Mounting; Measures For Reducing Operating Noise - Bosch FAS-420-TT Series Operation Manual

18 en | Technical specifications
3.5.7

Device Mounting

Mounting for FAS-420 series Aspirating Smoke Detector
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

3
Absorption of the operating noises caused by airflows
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.
2020.04 | 6.1 | F.01U.029.275
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Operation guide
Aspiration smoke detector LSN improved
1 Horizontal installation
2 Vertical installation
1 Smoke aspiration pipe
2 Flexible hose
3 Fitting
4 Vibration absorbers
Bosch Sicherheitssysteme GmbH