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Installation and connection
16
Pressure losses through friction
Duct or pipe friction resistance, i.e.
friction on the inside of the exhaust air
duct, affects the air flow as follows:
■
the smoother the internal wall
■
the larger the diameter of the internal
wall
■
the shorter the pipe
the lower the friction resistance.
Pressure losses due to fixtures
The exhaust air encounters further
resistance through fixtures built into the
pipe, e.g. diverters (bends, elbows,
angles), wall boxes with grids or
backpressure flaps.
Installation for pipe connection
■
inside diameter = 100 mm
In order to ensure the minimum
required air flow, a certain pressure
loss (resistance) must not be
exceeded.
The permissible total pressure loss
in an exhaust air duct must not
exceed a certain value. This is
calculated as the sum of all
individual pressure loss values for
the straight pieces and fixtures in the
exhaust air duct.
Note:
The value for the maximum
permissible total pressure loss for an
exhaust air duct is 50
*
.
■
inside diameter > 100 mm
If the pipe connection has an inside
diameter > 100 mm and total
pressure loss greater than 50*,
increase the inside diameter of the
pipe connection.
* To determine the total pressure loss
see table
Summary of Contents for WT34A201HK
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