Miele T 80 Series Technical Information page 69

T 80xx
Wall vent with flap
Wall vent with louvers
Smooth Bend
Calculating the maximum allowable length for 6" (150mm) ducting
When using 6" ducting, adequate air extraction is possible for an effective
duct length of up to 108 ft. (1296 in.)
To calculate the effective duct length, proceed as follows:
A) Measure the total length of the proposed ducting, including any bends.
B) Determine the amount, angle, and type of bends that will be required.
C) Determine what type of fitting will be used to terminate the duct at the
outer wall (flap vent, louvered vent, grill, etc.).
D) Using the chart below, add the additional length factor of the bends and
fittings that will be used to the total length measured in Step A above. If
the sum is less than 108 ft. (1296 inches), the hood will be able to
exhaust the air without any problem. If the sum is greater than 108 ft., an
external fan may be required.
Type of bend or fitting
Smooth bend
Elbow bend
Corrugated bend
Flexible metal duct
Wall vent with flap
Wall vent with louvers
R
Smooth Bend
R
90° Elbow
Angle of bend
45°
45°
90°
90°
45°
90°
90°
45°
45°
90°
90°
90° Elbow
69
Technical Information
Corrugated Bend
Radius of bend Additional length factor
4 inches
8 inches
4 inches
8 inches
8 inches
16 inches
8 inches
16 inches
R
Corrugated Bend
63 inches
157 inches
R
16 inches
10 inches
28 inches
19 inches
32 inches
152 inches
54 inches
40 inches
32 inches
46 inches
37 inches
63 inches
157 inches