Water and Wastewater Engineering - Sciences Club

TABLE 17-10
Typical minor loss factors ( K ) and Hazen-Williams friction factors (C) for high-service pumping
system
Item in
Figure 17-15 Description
a
Typical K values. Different publications present other values.
b
Reasonable value for mortar-lined steel pipe. Value can range from 130 to 145.
Source: Bosserman, 2000.
Pump 1
FIGURE 17-16
P ump manifold.
Pump 2
Pump 3
Summary of Pump Selection
The following steps summarize the pump selection process:
Pipe size Friction factor
mm m K a
1 Entrance (ordinary) 300 0.30 1.0
2 90� elbow 300 0.30 0.30
3 4.5 m of straight pipe 300 0.30 140
4 30� elbow 300 0.30 0.20
5 2 m of straight pipe 300 0.30 140
6 Butterfly valve 300 0.30 0.46
7 1.2 m of straight pipe 300 0.30 140
8 300 mm � 200 mm reducer 200 0.20 0.25
9 150 mm � 250 mm increaser 250 0.25 0.25
10 1 m of straight pipe 250 0.25 140
11 Pump check valve 250 0.25 0.80
12 1 m of straight pipe 250 0.25 140
13 Butterfly valve 250 0.25 0.46
14 0.60 m of straight pipe 250 0.25 140
15 90� elbow 250 0.25 0.30
16 1.5 m of straight pipe 250 0.25 140
17 Tee connection 250 0.25 0.50
To system
1. Plot the system head curves.
2. Modify the manufacturer’s head-discharge curve by subtracting the minor losses in the
pump suction and discharge piping.
STORAGE AND DISTRIBUTION SYSTEMS 17-35
C b