Miele PT 7136 - Example Duct Length Calculation

Example: Calculating the effective duct length and required internal
duct diameter
Rigid pipe Duct length
ft
Duct length
m
A
Wall duct with
louvered wall vent
12’ 5" 3.8 m
B
90° bend
2’ 7" 0.8 m
C
20" (0.5 m) rigid pipe
1’ 7" 0.5 m
D
90° bend
2’ 7" 0.8 m
E
left vent opening
3’ 3" 1.0 m
Total duct
length
22’ 5" 6.9 m
The total duct length is less than 33 feet (10 m), so a duct diameter of 4" (100 mm)
with adapter is sufficient.
Installation of exhaust venting
45