Calculating the total duct
length :
Friction against the inner walls of the
ducting will slow down the expelled air
as it passes through. An elbow, bend,
non-return flap or wall vent creates
more friction than a straight duct. The
friction created by each of these is
expressed as an
additional duct
length factor
. The additional length
factors are calculated by comparing
the friction created by, for example, an
elbow to that created by 1 metre of
straight plastic piping (Table I).
The additional duct length factor for
each item needs to be added together
to ascertain the
total duct length
required.
A larger
internal duct diameter
also
helps reduce friction. If the total duct
length is
more than 20 m
the duct
diameter should be increased (Table
II).
1. To calculate the total duct length
required:
^
First measure the distance which will
require straight ducting. Multiply this
amount by the corresponding
additional duct length factor in
Table I
.
^
Establish the number of angles,
bends etc. necessary and add their
additional duct length factors
together with the help of
Table I
.
^
Add all the additional duct length
factors together to get the total duct
length.
2. Internal duct diameter
^
Refer to
Table II
for the appropriate
duct diameter required.
Table I
Additional
duct length
factor
Flexible ducting*
–
1 m laid straight
–
45° angle
(Bend radius = 0.25 m)
–
90° angle
(Bend radius = 0.25 m)
1.8 m
1.5 m
2.5 m
Flexible aluminium vent hose* / plastic
piping
–
1 m laid straight / or 1 m
straight pipe
–
45° angle / elbow
(Bend radius = 0.25 m)
–
90° angle / elbow
(Bend radius = 0.25 m)
1.0 m
0.6 m
0.8 m
Wall vent kit* or window vent kit*
–
with louvred grille
–
with non-return flap (hinged
flap)
3.8 m
1.5 m
Non-return flap* to be
integrated into the vent
ducting
14.3 m
Flat ducting (for washer dryer
stack)*
11.0 m
Venting connection to the
left/right
1.0 m
*optional accessory from Miele
Table II
Maximum total
duct length allowable
Internal duct
diameter required
20 m
40 m
100 m
100 mm
125 mm
150 mm
Installation - venting
33
Summary of Contents for t 8302
Page 51: ...51 ...
Page 52: ...Alteration rights reserved 1212 M Nr 07 868 650 02 ...
