Bs 6700 2006 Water Supply Services Formulated

Licensed copy:Southbank University, 13/05/2008, Uncontrolled Copy, ® BSI w

Table D.4

Example of pipe sizing calculations for cold water services

CO

©

a to

o o 05

Pipe

Flow rate

reference

Total

Pipe size

Velocity V

Design

m 1

Head lossiJ

Drop + Rise —

Available head (7 + 14)

Pipe length

LU

Vs

DN

2

3

4

m/s

kPa/m

kPa

kPa

m

5

6

7

8

9

Main service pipe - for this example the minimum head in main = 9 + list 0.6 + 0.3 0.9 6 + list 0.4 + 0.2 0.6 3 + list 0.2 +0.1 0.3 3 + list 0.3

1 to 2 2 to 3 3 to 4 4 to 5

Actual

Head loss Effective

m

Pipe (10x6) kPa

Valves*) kPa

10

11

12

2 SV = 21

300 kPa (3 bar)

28

1.7

1.4

-50

250

25

35

49

22

2.0

2.5

-30

150

3

4.2

11

15

2.2

5

-30

109

3

4.2

21

15

2.2

5

+ 10

98

1

1.4

7

5 to 6

0.2

15

1.5

2.3

+ 10

83

6

8.4

20

SV = 18

5 to 7

0.1

15

0.75

0.6

-5

68

1

1.4

1

+20

20

4

5.6

1.4

Cold water distributing pipes in flats Cl to C2

13.5

0.35

28

0.63

0.25

C2 to C3

11.5

0.32

22

1

0.8

—

18.6

1

1.4

C3 to C4

10.0

0.30

22

0.9

0.65

-6

11.4

1.5

2.1

1.4

C3 to C5

1.5

0.15

15

1.1

1.3

-7

10.4

0.7

1.0

1.3

C2 to C6

2.0

0.10

15

0.7

0.6

-7

11.6

1

1.4

0.9

1.2

Gate valve =0

oss

Residual Total (11 + 12) kPa

Available (8 - Fitting type 13) kPa

Required

Surplus

kPa

kPa

13

14

15

16

17

70

180

11

139

21

88

25

73

20

63

sink float

5

58

1

67

valve (5 mm 4>)

30

37

1.4

18.6

1.2

17.4

1.4

10

bath

8

2

1.3

9.1

wash basin

8

1.1

10.7

WC cistern (6.5mm §)

10

0.7

0.9