Length Change Of The Pipe System; Air Sampling Openings - Bosch FAS-420-TM Operation Manual

68 en | Installation of the Pipe System
5.1

Length Change of the Pipe System

Length changes (extensions and reductions) of the pipes are caused by temperature changes.
Temperature increases cause lengthening of the pipes, temperature drops cause shortening
of the pipes. The length change must be given particular consideration if the temperature of
the pipe system at the time of installation deviates from the normal operating temperature.
The length change can be calculated using the following formula:
where
ΔL
L
ΔT
δ
PVC
δ
ABS
For example, a temperature change of 10 °C on a 10 m-long PVC pipe causes a length change
of 8 mm.
Mounting clamps
PVC pipe clips are used as standard for installing the pipe system. These clips do not allow
any length extensions.
Figure 5.1 Overview of mounting clamps
5.2

Air Sampling Openings

Figure 5.2 Example of an aspiration boring with aspiration reduc-
ing film sheet
Air sampling openings
Select the structure of the air sampling opening (aspiration boring) and the position in the
pipe system according to the project specification and taking into account the planning
guidelines.
F.01U.088.878 | 4.1 | 2010.11
= Length change in [mm]
= Length of the pipe to be calculated in [m]
= Maximum temperature difference in [°C]
= 0.08 mm/m x °C
= 0.101 mm/m x °C
1 2
4 2
1
1 Standard mounting clamps for 25 mm pipe
2 Plastic mounting clamps for 25 mm pipe, for
length changes and temperatures of up to -40 °C
3 Spring steel clamp for 25 mm pipe, for high-rise
3
warehouses and temperatures of up to -40 °C
5 6 4 3
Operation Guide
FAS-420-TM Aspirating Smoke Detector
1 Smoke aspiration pipe
2 Aspiration reducing film sheet with
air sampling opening
3 Marking tape for aspiration
reducing film sheet
Air sampling opening
4
Fire red (RAL 3000)
5
Transparent
6
Bosch Sicherheitssysteme GmbH