Page 16 EN 12056-2:2000
Table 2 — Discharge units (DU ) (DU ) Appliance
System I
System II
System III
System IV
DU l/s
DU l/s
DU l /s
DU l /s
W ash basin, bidet Shower without plug Shower with plug
0,5 0,6 0,8
0 ,3 0,4 0,5
0,3 0,4 1,3
0,3 0,4 0,5
Single urinal with cistern Urinal with flushing valve Slab urinal
0 ,8 0 ,5 0 ,2 *
0 ,5 0,3 0,2*
0,4 0,2*
0,5 0,3 0,2*
Bath Kitchen sink Dishwasher (household)
0,8 0,8 0,8
0,6 0,6 0,6
1,3 1,3 0,2
0,5 0,5 0,5
W ashing machine up to 6 kg W ashing machine up to 12 kg W C with 4,0 l cistern
0,8 1,5 **
0,6 1,2 1,8
0,6 1,2 **
0,5 1,0 **
W C with 6,0 l cistern W C with 7,5 l cistern W C with 9,0 l cistern
2,0 2,0 2,5
1,8 1,8 2,0
1,2 to 1,7***
2,0 2,0 2,5
1,4 to 1,8*** 1,6 to 2,0***
Floor gully DN 50 0,8 0,9 Floor gully DN 70 1,5 0,9 Floor gully DN 100 2,0 1 ,2 * Per person. ** Not pe permitted. *** Depending Depending upon upon type type (valid (valid for for WC’s with siphon flush cistern cistern only). only). Not used or no data.
0,6 1,0 1,3
6.2.3
Discharge from non-domestic sanitary appliances Discharges from non-domestic sanitary appliances (e.g. commercial kitchen) should be determined individually.
6.3
Calculation of flowrate
6.3.1
Waste water flowrate (Q ww ww) Qww is the expected flowrate of waste water in a part or in the whole drainage system where only domestic sanitary appliances (see Table 2) are connected to the system. Qww K DU
where: Qww K
= Waste Waste wat water er flo flowr wrat ate e (l/s (l/s)) = Frequency factor of di disch scharge un units DU = Sum of
6.3.2
Frequency factor (K ) Typical frequency factors associated with different usage of appliances are given in Table 3.
© BSI 09-2000
Page 17 EN 12056-2:2000 Table 3 — Typical frequency factors (K ) K
Usage of appliances
6.3.3
Intermittent use, e.g. in dwelling, guesthouse, office Frequent use, e.g. in hospital, school, restaurant, hotel
0,5 0,7
Congested use, e.g. in toilets and/or showers open to public Special use, e.g. laboratory
1,0 1,2
Total flowrate (Q tot) Qtot is the design flowrate in a part or in the whole drainage system where sanitary appliances, appliances with continuous flow and/or waste water pumps are connected to the system. Continuous flows and pump discharge rates shall be added to the waste water flowrate without any reduction. Qtot
= Qww + Qc + Qp
Qtot Qww Qc Qp
= Total flowrate (l/s) = Waste water flowrate (l/s) Continuous flowrate (l/s) = Pumped water flowrate (l/s)
where:
6.3.4
Calculation rules The pipe capacity ( Qmax) shall be at least the larger of: a)
the calculated waste water flowrate (Qww) or total flowrate ( Qtot); or
b)
the flowrate of the appliance with the largest discharge unit (see Table 2).
For convenience some values of Qww or Qtot calculated for different frequency factors ( K ) and sums of discharge units (DU) are tabulated in annex B.
6.4
Layout of branches
6.4.1
Unventilated discharge branches Sizes and limitations upon the use of unventilated discharge branches are given in Tables 4 and 5. Where the limitations cannot be met, discharge branches shall be ventilated, unless national and local regulations and practice allow the use of larger pipe sizes or air admittance valves. Limitations given in Table 5 are simplifications. For further information see national and local regulations and practice.
© BSI 09-2000
