System Calculation For Concentric Flue Duct - KAL-FIRE Fairo 60 User Manual

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
st
1 vertical metre
nd
2 and next vertical metre
Horizontal metre
Vertical elbow 90° (A)
Vertical elbow 45°
Horizontal elbow 90° (B)
Horizontal elbow 45°
Result
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
The longer the duct, the longer it will take before you get
attractive flames.
Calculation example
Flue/chimney calculation
st
1 vertical metre
nd
2 and next vertical metre
Horizontal metre
Vertical elbow 90° (A)
Vertical elbow 45°
Horizontal elbow 90° (B)
Horizontal elbow 45°
Result*
*The sum of all values must be zero or positive, otherwise the Fairo will not function
according to EN613.
4. Mounting and installation
Value per Max.
metre Value
9
1
-1
-2
-1
-4
-2
0 / positive
Example: Value per m:
number of a number, no
elements quantity
used (X)
1
10
9
11
A
-7
-6
-8
Total
value
example
(Y) (X * Y)
9 9
1
-1
-2
-1
-4
-2
A
B
12m
7m
Max.
permit-
ted
value
9
11
-7
-6
-8