MAKKAH MALL
CALCULATION FOR PRASSURE LOSS
TOTAL WATER DEMAND FOR BUILDINGS IS = 142 gpm (see attached)
The Actual flow rate from tank = 142 gpm
Calcuation of Total Pressure Losses
Friction Head :
By Using Hazen - Williams Equation
1.852
v
h = L .f f = { 1.318 .C . R0.63
}
V = Velocity (fps ) = Q/A
C = Hazen - Williams Coefficient
R = Hydraulic Redius = Area/ Wetted Perimeter = D / 4
L = Equivalent length
f = pressure loss ft/ft
1 . Friction loss from pump room to point - 1
kind of Pipe & Dai .( D )250
160 mm (OD) UPVC = 75 mm(ID)= 0.246 ft
Hazen-Williams Coefficient - ( C ) = 150 (see attached)
= = 3
Flow Rate ( Q ) 142 gpm 0.0090 m3/S 0.316 ft /SEC
Hydraulic Redius ( R ) = D / 4 = 0.0615 ft
Q 0.316
Velocity ( V ) { ת D
2 } V= { 0.785 0.06052
} = 6.659 ft/SEC
4
1.852
6.659
Friction loss f = { 1.318 150 0.17258 } = 0.04851 ft/ft
Length L= 158 m 518.24 ft
Equivalent length for elbow 90 = 10 ft 20 ft
Equivalent length for gate valve = 2 ft 2 ft
Equivalent length for Tee = 15 ft 45 ft
Total Length = 585.24 ft
h = L .f h= 28.39 ft
2 . Friction loss from point - 1 to point - 2
kind of Pipe & Dai .( D )250
160 mm (OD) PP = 65 mm(ID)= 0.213 ft
Hazen-Williams Coefficient - ( C ) 140 (see attached)
= = 3
Flow Rate ( Q ) 59.3 gpm 0.0037 m3/S 0.132 ft /SEC
Hydraulic Redius ( R ) = D / 4 = 0.0533 ft
Q 0.132
Velocity ( V ) { ת D
2 } V= { 0.785 0.04545
} = 3.702 ft/SEC
4
1.852
3.702
Friction loss f = { 1.318 140 0.157702 } = 0.02196 ft/ft
Length L= 13.2 m 43.296 ft
Equivalent length for Tee = 12 ft 24 ft
Total Length = 67.30 ft
h = L .f h= 1.48 ft
3 . Friction loss from point - 2 to point - 3
kind of Pipe & Dai .( D )250
160 mm (OD) PP = 50 mm(ID)= 0.164 ft
Hazen-Williams Coefficient - ( C ) 140 (see attached)
= = 3
Flow Rate ( Q ) 31.0 gpm 0.0020 m3/S 0.069 ft /SEC
Hydraulic Redius ( R ) = D / 4 = 0.041 ft
Q 0.069
Velocity ( V ) { ת D2
} V= { 0.785 0.0269
} = 3.271 ft/SEC
4
1.852
3.271
Friction f = { 1.318 140 0.133676 } = 0.02371 ft/ft
Length L= 33.6 m 110.208 ft
Equivalent length for elbow 90 = 7 ft 21 ft
Equivalent length for GV= 1.3 ft 1.3 ft
Equivalent length for Tee = 10 ft 20 ft
Total Length = 152.51 ft
h = L .f h= 3.62 ft
4 . Friction loss from point - 3 to point - 4
kind of Pipe & Dai .( D )250
160 mm (OD) PP = 40 mm(ID)= 0.131 ft
Hazen-Williams Coefficient - ( C ) 140 (see attached)
= = 3
Flow Rate ( Q ) 23.0 gpm 0.0015 m3/S 0.051 ft /SEC
Hydraulic Redius ( R ) = D / 4 = 0.0328 ft
Q 0.051
Velocity ( V ) { ת D
2 } V= { 0.785 0.01721
} = 3.792 ft/SEC
4
1.852
3.792
Friction f = { 1.318 140 0.116145 } = 0.04045 ft/ft
Length L= 13 m 42.64 ft
Equivalent length for Tee = 7 ft 7 ft
Total Length = 49.64 ft
h = L .f h= 2.01 ft
5 . Friction loss from point - 4 to point - 5
kind of Pipe & Dai .( D )250
160 mm (OD) PP = 32 mm(ID)= 0.105 ft
Hazen-Williams Coefficient - ( C ) 150 (see attached)
= = 3
Flow Rate ( Q ) 21.8 gpm 0.0014 m3/S 0.049 ft /SEC
Hydraulic Redius ( R ) = D / 4 = 0.02624 ft
Q 0.049
Velocity ( V ) { ת D
2 } V= { 0.785 0.01102
} = 5.616 ft/SEC
4
1.852
5.616
Friction f = { 1.318 150 0.100913 } = 0.09559 ft/ft
Length L= 4.2 m 13.776 ft
Equivalent length for gate valve = 0.8 ft 0.8 ft
Equivalent length for Tee = 6 ft 12 ft
Total Length = 26.58 ft
h = L .f h= 2.54 ft
6 . Friction loss from point - 5 to point - 6
kind of Pipe & Dai .( D )250
160 mm (OD) PP = 25 mm(ID)= 0.082 ft
Hazen-Williams Coefficient - ( C ) 140 (see attached)
= = 3
Flow Rate ( Q ) 21.4 gpm 0.0013 m3/S 0.048 ft /SEC
Hydraulic Redius ( R ) = D / 4 = 0.0205 ft
Q 0.048
Velocity ( V ) { ת D
2 } V= { 0.785 0.00672
} = 9.032 ft/SEC
4
1.852
9.032
Friction f = { 1.318 140 0.086378 } = 0.34929 ft/ft
Length L= 11 m 36.08 ft
Equivalent length for gate valve = 0.6 ft 0.6 ft
Equivalent length for elbow= 3 ft 12 ft
Total Length = 48.68 ft
h = L .f h= 17.00
= = = =
Total Friction loss along pipes is = 55.04 ft = 16.78 m
Static pressure is 19 m = 62.3 ft
Residual head :
the required residual pressure at furthest fixture unit is 15 psi for flush valve and 8 psi for flush tank
Total Dynamlc Head = Static Head + Friction Head + Residual head
Total Dynamlc Head = 62.30 ft + 55.04 ft + 18.50 ft = 135.84 ft
= 41.41 m
NEED 142 gpm and 4 bar (Two Pump one duty, one stand by)
