Building Services Engineering 5th Edition Handbook

190 Hot- and cold-water supplies
53 0.31
1589
22
8 0.05
3 0.02
8 0.05
– 0.16
1589
15
WC
1589
15
Basin
WC
1589
15
Bath
1150
15
31 0.20
23 0.15
20 0.13
12 0.08
22 0.14
1589
22
1589
22
1589
22
1589
22
2511
15
3 0.02
WC Basin Sink
2511
15
8 0.05
14 0.10
11 0.075
2511
15
2511
15
2511
15
6.9 Pipe-sizing working drawing for Example 6.2.
The pipe-sizing data are shown in Fig. 6.9. Taps and ball valves will be 15 mm on domestic
sanitary appliances and 22 mm on baths. DU values are taken from Table 6.2: WC, 8; basin, 3;
sink, 11; bath, 12. These are entered into the appropriate boxes on the working drawing and
then totalled back to the water main. Great accuracy is not needed in reading the water flow
rates appropriate to each DU.
The heads of water causing flow are 4 m for the upper floor and 8 m for the lower floor.
The measured length of pipe from the storage tank to the furthest fitting on the upper floor, the
bath, is:
L 1 = (4 + 1 + 4 + 4 + 2 + 3 + 1) m = 19 m
and the equivalent length of the circuit to the bath is,
EL 1 = 1.3 × 19 m
= 24.7 m
Similarly, the equivalent length for the lower floor circuit to the sink is:
EL 2 = 1.3 × (4 + 1 + 3 + 1 + 4 + 10 + 1) m = 31.2 m