22
Wavin AS+
Technical Manual
Phone. +31(0)38 42 94 951
Basis of calculations
The hydraulic calculations for a waste water system begin at
the starting point (e.g. a sink, toilet or shower, etc.) and cover
the rest of the piping, the layout of which depends on the
items included.
Single connection pipe
Collecting connection pipe
Downpipe
Collecting pipe
Underground and collector pipe
Please refer to the following pages of the manual for further
details of the areas covered by the waste water drainage
pipes. The sum total quantities of waste water to be disposed
of are normally based on various parameters.
The formula for calculating domestic waste water in accor-
dance with DIN 12056 is as follows:
Fig. 11: Minimum fall for waste water pipes, example.
A
C
D
B
Basis of calculation DIN EN 12056:
Q˙
tot
= Q˙
WW
+ Q˙
C
+ Q˙
P
Q˙
WW
= Wastewater discharge
[flow rate of waste water]
Q˙
tot
= Total wastewater discharge [l/s]
[flow rate, total]
Q˙
C
= Continous discharge [l/s]
[flow rate, constant]
Q˙
P
= Pump flow rate
[flow of discharge from pumps]
DU = Design unit
[design unit]
Q˙
WW
= K · ∑ DU
A
Unventilated connection pipe
min. 1.0%
B
Ventilated connection pipe
min. 0.5%
C
Collecting pipe wastewater > DN 100
min. 0.5%
Collecting pipe wastewater DN 90
min. 1.5%
D
Collecting pipe rainwater
1:DIN
