Bosch FAS-420-TM - Monitoring with Forced Airflow

FAS-420-TM Aspirating Smoke Detector Installation of the Pipe System | en 71
Bosch Sicherheitssysteme GmbH Operation Guide F.01U.088.878 | 4.1 | 2010.11
5.4 Monitoring with Forced Airflow
5.4.1 Detection at Intake and Exhaust Openings
5.4.2 Detection in the Bypass
For details on connecting the air return, please see Section 5.6 Air-return pipe, page 72.
For FAS-420-TM planning in these applications, see Section 3.9 Planning for forced airflow,
page 52.
CAUTION!
If the smoke aspiration occurs in a forced airflow (fan, air-conditioning units), direct the air
sampling openings depending on the exhaust speed in the airflow (see Figure 5.4).
Figure 5.4 Positioning the air sampling opening depending on air
speed
1 Aspiration pipe with air sampling
openings
2Exhaust speed <0.5m/s
3Exhaust speed >0.5m/s
1
23
30°
Figure 5.5 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
12
3
4
b
1/2 b