Drilling The Aspirating Holes - Siemens FDA241 Planning, Mounting

Mounting/Installation
5
Installing the pipe system

5.2.5 Drilling the aspirating holes

52 | 56
Building Technologies
Fire Safety
The diameter and position of the aspirating holes in the pipe system and in the end
caps are defined during planning.
The aspirating holes are drilled once the pipe system has been installed.
Information about drilling the aspirating holes
You must observe the following when drilling the aspirating holes:
Only drill the planned diameter in the pipe system. Deviations from the planned
diameter influence the effectiveness of the aspirating smoke detector.
The planned diameter may deviate from one pipe to another. You should
therefore check the required diameter before drilling and use the appropriate
drill.
Always drill the aspirating holes at a right angle to the pipes. If you do not drill
at a right angle, the aspirating hole will not be circular and will therefore deviate
from the planned diameter or impair the flow of air in the pipe system.
Drill the aspirating holes from the bottom upwards.
Do not drill through both walls of the pipe! Only drill in one wall of the pipe.
Drill at a slow speed and with a sharp drill. This prevents dust or swarf entering
the pipe system and impairing the effectiveness of the aspirating smoke
detector.
Deburr the drilled holes if necessary. The drilled holes must not be
countersunk!
Labels can be stuck to the aspirating holes to identify them. The opening in the
labels must be placed around the aspirating hole.
Work steps
The pipe system is installed.
Information about the position and diameter of the aspirating holes is available.
Information about the diameter of the holes in the end caps is available.
1. Drill the aspirating holes at a right angle to the pipes.
– Ensure that the aspirating holes in the pipe always face down.
2. Drill an aspirating hole in every end cap.
3. Purge the pipe system of possible swarf by blowing it out.
The pipe system is ready for connection to the aspirating smoke detector.
If the pipe system design dictates that an aspirating hole ought to be drilled in a
fitting, proceed as follows:
Do not drill into the fitting under any circumstances! The resulting turbulence
could impair the measurement result of the aspirating smoke detector.
Instead, offset the drilled hole in relation the fitting by moving it further along the
flow in the direction of the aspirating smoke detector, as illustrated in the graphic
below. Offsetting the drilled hole by up to 100 mm has no impact on the results
detected by the aspirating smoke detector.
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2017-09-12