KAL-FIRE Fairo 60 - 4.3.1 System calculation for concentric flue duct

4. Mounting and installation
10
4.3.1 System calculation for concentric flue duct
Use the following rules of thumb to calculate the flue duct. The
calculations apply to the wall and roof ducts. If you use calculations
different to those shown below, Kal-fire can give no safeguard or
guarantee for the Fairo.
Flue/ chimney calculation
Value per
metre
Max.
Value
1
st
vertical metre
9
9
2
nd
and next vertical metre
1
11
Horizontal metre
-1
-7
Vertical elbow 90° (A)
-2
-6
Vertical elbow 45°
-1
Horizontal elbow 90° (B)
-4
-8
Horizontal elbow 45°
-2
Result
0 / positive
If you use too many elbows and mount the duct in a rather horizontal
position, too much resistance will be created in the flue. The combustion
air will have difficulty reaching the Fairo, which will considerably change
the effect of the flames.
Always start with 1 metre of vertical pipe section!
Maximum permitted total system length
Maximum permitted horizontal system length
12m
7m
The longer the duct, the longer it will take before you get
attractive flames.
Calculation example
Flue/chimney calculation
Example:
number of
elements
used (X)
Value per m:
a number, no
quantity
(Y)
Total
value
example
(X * Y)
Max.
permit-
ted
value
1
st
vertical metre
1
9
9
9
2
nd
and next vertical metre
1
11
Horizontal metre
-1
-7
Vertical elbow 90° (A)
-2
-6
Vertical elbow 45°
-1
Horizontal elbow 90° (B)
-4
-8
Horizontal elbow 45°
-2
Result*
*The sum of all values must be zero or positive, otherwise the Fairo will not function
according to EN613.
B
A
A