MAN3186 - TITANUS MICRO
•
SENS®
105
Aspiration pipe length = overall pipe length
– (length of air return * factor a)
Aspiration pipe length = 50 m
– (10 m * 1.6) = 34 m
5.3.6 Project planning with air return
In cases where there are air pressure differences between the area of the
TITANUS MICRO·SENS® and the area of the aspiration apertures, air return
of the drawn-in sample air into the pressure area of the aspiration apertures
may be necessary. For this, a correspondingly long aspiration pipe must be
connected to the air outlet of the TITANUS MICRO·SENS®.
As air return can have a negative effect on the transport time of the
aspirating smoke detector, the effect of air return on the permissible overall
pipe length must be considered.
Air return with a
∅
40 mm pipe does not have any influence and can be
planned and/or retrofitted without reducing the overall pipe length.
Consideration of air returns:
In order to calculate the maximum aspiration pipe length, the length of the air
return must be multiplied with the respective factor a and subtracted from the
permissible overall pipe length.
Factors for determining the influence of air return on the overall pipe length:
Length of air return
Factor a for
air return
∅
25 mm
Factor a for
air return
∅
32 mm
0 to 5 m
0.0
0.0
> 5 to 10 m
1.6
0.0
> 10 to 25 m
3.2
1.0
Table 46:
Factors for determining the influence of air returns
Example: An air return (
∅
25 mm) of 10 m is to be connected to a
TITANUS MICRO·SENS®. The permissible overall pipe length for the pipe
system is 50 m. The following results for the maximum aspiration pipe
length:
