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ROOFMASTER STEF
Air ow measurement
Air
measurement
STEF roof fans in normal version (not in ATEX or smoke
extraction version) can be supplied with air w
measurement FLOW. Air
is measured as
l
pressure measurement with a manometer. Measuring
nipples are placed behind a cover and they are marked
with +/-, see Figure 5. The accuracy in normal conditions
is 10%.
The air
can be calculated at air density of 1,2 kg/m
3
as follows:
where
Q
v
= air ow
∆
p
m
= pressure
e
K
= factor for given fan size
K-factors are given in the table below:
Mounting of the fan
When the roof fan is equipped with the air w
measurement the fan must be mounted on the MORA
mounting frame. MORA is included in the delivery
of FLOW. The gaskets for upper and lower side of the
frame are included loose in the delivery.
Mounting (Figure. 6)
1. Attach the gaskets to the mounting frame
2. Install the mounting frame to the chimney
3. Mount the roof fan on the frame
K-Factors
FLOW
2
3
4
5
6
7
K
37,08
23,72
22,64
15,33
10,41
5,89
STEF
2
3
4
5
6
7
Fig. 5 Measuring nipples
Q
v
=
√
∆
p
m
K
Fig. 6 Mounting
STEF
Gasket
Mounting frame
Gasket
Duct
Safety switch
(optional)
