ACV International
19
5.7.2
Equivalent lengths
Bend 90°
R/D=1
2 m
Bend 45°
R/D=1
1 m
Elbow 90°
R/D=0,5
4 m
Elbow 45°
R/D=0,5
2 m
In the case of larger or smaller pipe diameters the permissible pipe length is greater or
smaller respectively.
In the case of smaller diameters the following applies:
Ø70: 0,59x the permissible pipe length for ø80
Ø60: 0,32x the permissible pipe length for ø80
Ø50: 0,15x the permissible pipe length for ø80
Contact the manufacturer for check calculations for the resistance of the air supply and
combustion gas flue pipe and the wall temperature at the end of the combustion gas
flue pipe.
5.7.3
Sample calculation
Pipe
Pipe lengths
Total pipe length
Flue pipe
L1 + L2 + L3 + 2x2 m
13 m
Air supply
L4 + L5 + L6 + 2x2m
12 m
Note
•
The total pipe length is:
Sum of the straight pipe l sum of the equivalent pipe lengths of
bends/elbows.
•
Permissible length of air supply pipe and flue outlet pipe totals 85 m, excluding the
lenght of the combi duct or the dual-pipe duct.
