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Wavin AS+
Technical Manual
Phone. +31(0)38 42 94 951
Kitchen downpipes
A maximum of four kitchens may be connected to a DN 70
downpipe. If more than four kitchens are connected, waste
water discharge calculation Qww must be verified and the
dimensions of the downpipe increased.
Layout
Waste water downpipes must be installed:
without any change of nominal diameter
as straight as possible via the individual floors
and up to the roof
Connections measuring ≤ DN 70 must be used with branches
of 87.5°.
Neighbouring residential buildings may only be connected to
a shared waste water pipe under certain conditions.
1. Conformity with required fire-prevention measures
2. Conformity with noise-protection requirements
Corresponding installation measures are also required for
waste water downpipes that change direction, due to the
resulting pressure ratios.
Offsets requiring ≤ 1 metre and ≤ 45° may be used. Larger
offsets require two 45° bends and a 250 mm coupler. Wavin
offers ready-made solutions for this purpose in the form of
extended bends, for example.
Different rules are to be observed, depending on the height
of the downpipe, when directing downpipes into a collecting
pipe. Failure to observe these rules may lead to build-ups of
pressure or undesired vacuums in the upstream/downstream
section on either side of the change of direction.
This can in turn cause sink traps to be sucked empty, leading
to bad smells, or to seepage of waste water into the affected
area.
DIN 1986-100 therefore makes the following distinctions:
Downpipes of up to 10 m in height
On downpipes of less than 10 m in length, the change of
direction in the horizontal pipe may be carried out using an
87.5° bend. However, a technically more ideal solution, from
a hydraulic and noise-prevention point of view, is to base the
change of direction on two 45° bends.
Downpipes of > 10 m to 22 m in height
In the case of downpipe offsets >2 m, the following areas
should be kept free of drainage connection points:
1. Min. 2m above the bend on the inlet side.
2. Min. 1m downstream of the outflow bend and 1 m
upstream of the outflow bend of an offset running to a
horizontal pipe.
This does not apply to downpipe offsets with a change of
direction of up to 45°.
In the case of a downpipe offset, the bends on the inlet and
outflow side should be fitted with a 250 mm extended bend.
Fig. 12: Wavin AS+ long bend.
250
mm
