Bosch FAS-420-TM Operation Manual page 54

54 en | Planning
F
A
Figure 3.18 Air-return pipe
The open end of the air-return pipe is sloped at an angle of 45° (see Figure 5.5, Page 71).
The distance of the air sampling openings to one another and to the duct wall is represented
in the following table.
Bore distances
Distance of the air sampling openings to the
wall
Distance of the air sampling openings to one
another
Diameter of the air sampling openings
The diameter of the air sampling openings is derived from the number of air sampling
openings. The precise value can be obtained from Section 3.8 Simplified pipe planning.
The pipe is closed with an end cap without bore hole.
Arrangement
The air sampling openings must face the airflow.
Note when planning that the air-conditioning ducts are often only accessible from two sides
for installation of the pipe system.
Example
Figure 3.19 shows two planning examples of pipe systems in air-conditioning ducts.
F.01U.088.878 | 4.1 | 2010.11
1 2
FAS / FCS
3
5
4
3
2
A
FAS / FCS
2
1/2 b
5
1
v
4
v
3
v
2
B
v
1
Duct cross-section
≤ 0.5 m²
100 to 200 mm
100 mm
Operation Guide
FAS-420-TM Aspirating Smoke Detector
F
Front view
A Plan view
1 Air-conditioning duct
Duct adapter
2
3 Airflow
b
4 Aspiration
5 Air-return pipe
b Width of air-conditioning
duct
v - v Flow speed
1 4
Duct cross-section
≤ 0.5 m²
200 to 300 mm
150 mm
Bosch Sicherheitssysteme GmbH