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130 131
CONVERSION TABLE
Reference
1
132 133
SI UNIT
Reference
Item
Force
Pressure
Mass
Speed
Viscosity
Dynamic Viscocity
Specific heat
Work energy
Power
Existing Unit (SI Unit)
1kgf ( = 9.80665N )
1kgf/cm3 ( = 0.0980665MPa )1mAq ( = 9.80665kPa )1mmHg ( = 0.133322kPa )
1kW.h ( = 3.6MJ )1kgf.m ( = 9.80665J )1kcal ( = 4.18605KJ )1kgf.m/s ( = 9.80665W )1PS ( = 7.355 x 10-1kW )1kcal/h ( = 1.16279 x 10-3kW )
Mass: 1kg ( =1kg )
Revolution speed: 1r.p.m.( =1min-1 )
1cP ( = 1mPa.S )
1cSt ( = 1mm2/s )
1kcal/kg. c ( = 4.18605kJ/(kg.K) )
SI Unit
1N ( = 0.101972kgf )
1MPa ( = 10.1972kgf/cm2 )1kPa ( = 0.101972mAq)1kPa ( = 7.50062mmHg )
1MJ ( = 2.77778 x 10-1kW.h )1J ( = 1.01972 x 10-1kgf.m )1KJ ( = 2.38889 x 10-1kcal )1kW ( = 1.01972 x 102kgf.m/s )1kW ( = 1.35962PS )1kW ( = 8.60 x 102kcal/h)
Mass: 1kg ( =1kg )
Revolution speed: 1min-1( =1r.p.m. )
1mPa.S ( = 1cP )
1mm2/s ( = 1cSt )
1kJ/(kg. K) ( = 0.238889kcal / (kg. c) )
TRANSLATION TO UNIT (SI)
TO DETERMINE: AMPERES, HORSEPOWER, KILOWATTS, AND KVA
To find
Amperes when horsepower is known
Direct current Single-phase Three-phase
H.P. x 746E x %Eff.
H.P. x 746E x %Eff. x P.F.
H.P. x 7461.73 x E x %Eff. x P.F.
Amperes when kilowatt is known
K.W. x 1000E
I x E1000
I x E x %Eff.746
K.W. x 1000E x P.F.
K.W. x 10001.73 x E x P.F.
Amperes when KVA is known
K.W. x 1000E
K.W. x 10001.73 x E
Kilowatts I x E x P.F.1000
I x E x x 1.73 x P.F.1000
KVA I x E 1000
I x E x 1.731000
Horsepower output I x E x %Eff. x P.F.746
I x E x 1.73 x %Eff.x P.F.746
Where:A : AmperesE : Volts%Eff. : per cent efficiencyP.F. : Power Factor
K.W. : KilowattsKVA : Kilo-volt-amperesH.P. : HorsepowerI : Current
ELECTRICAL DATA
2
132 133
SI UNIT
Reference
Item
Force
Pressure
Mass
Speed
Viscosity
Dynamic Viscocity
Specific heat
Work energy
Power
Existing Unit (SI Unit)
1kgf ( = 9.80665N )
1kgf/cm3 ( = 0.0980665MPa )1mAq ( = 9.80665kPa )1mmHg ( = 0.133322kPa )
1kW.h ( = 3.6MJ )1kgf.m ( = 9.80665J )1kcal ( = 4.18605KJ )1kgf.m/s ( = 9.80665W )1PS ( = 7.355 x 10-1kW )1kcal/h ( = 1.16279 x 10-3kW )
Mass: 1kg ( =1kg )
Revolution speed: 1r.p.m.( =1min-1 )
1cP ( = 1mPa.S )
1cSt ( = 1mm2/s )
1kcal/kg. c ( = 4.18605kJ/(kg.K) )
SI Unit
1N ( = 0.101972kgf )
1MPa ( = 10.1972kgf/cm2 )1kPa ( = 0.101972mAq)1kPa ( = 7.50062mmHg )
1MJ ( = 2.77778 x 10-1kW.h )1J ( = 1.01972 x 10-1kgf.m )1KJ ( = 2.38889 x 10-1kcal )1kW ( = 1.01972 x 102kgf.m/s )1kW ( = 1.35962PS )1kW ( = 8.60 x 102kcal/h)
Mass: 1kg ( =1kg )
Revolution speed: 1min-1( =1r.p.m. )
1mPa.S ( = 1cP )
1mm2/s ( = 1cSt )
1kJ/(kg. K) ( = 0.238889kcal / (kg. c) )
TRANSLATION TO UNIT (SI)
TO DETERMINE: AMPERES, HORSEPOWER, KILOWATTS, AND KVA
To find
Amperes when horsepower is known
Direct current Single-phase Three-phase
H.P. x 746E x %Eff.
H.P. x 746E x %Eff. x P.F.
H.P. x 7461.73 x E x %Eff. x P.F.
Amperes when kilowatt is known
K.W. x 1000E
I x E1000
I x E x %Eff.746
K.W. x 1000E x P.F.
K.W. x 10001.73 x E x P.F.
Amperes when KVA is known
K.W. x 1000E
K.W. x 10001.73 x E
Kilowatts I x E x P.F.1000
I x E x x 1.73 x P.F.1000
KVA I x E 1000
I x E x 1.731000
Horsepower output I x E x %Eff. x P.F.746
I x E x 1.73 x %Eff.x P.F.746
Where:A : AmperesE : Volts%Eff. : per cent efficiencyP.F. : Power Factor
K.W. : KilowattsKVA : Kilo-volt-amperesH.P. : HorsepowerI : Current
ELECTRICAL DATA
COMMONLY USE PUMP FORMULAS
Reference
HEAD AND PRESSURE
BRAKE HORSEPOWER OR BRAKE KILOWATTTo determine the horsepower or kilowatt required, the following formulas can be used:
= )tf( daeH = )m( daeH
Head (m) = Head (ft) x 0.305
Head (ft) = Head (m) x 3.28
a) Brake horsepower =
b) Brake horsepower =
c) Brake Kilowatt =
Where n = Speed, Q = Flow, H = Head, P = Power
FORMULAS
V =
Total Head (ft) x IGPM x Sp. Gr.pump efficiency % x 3300
pressure (kPa) or9.8 x specific gravitypressure (bar) x 10.2
specific gravity ;pressure (psi) x 2.31
specific gravity
Total Head (ft) x USGPM x Sp. Gr.pump efficiency % x 3960
Total Head (m) x m3/hr x Sp. Gr.pump efficiency % x 367
GPM x 0.321F
2.31 x psiSp. Gr.*
= GPM x 0.409(I.D.)2
V2 = 2 gH
H =
1.134 x inches of mercurySp. Gr.*
H =
141.5131.5 + AP 1 (Baume)
Sp. Gr.*=
ABBREVIATIONS
V
GPM
F
I.D.
g
H
HP
Sp. Gr.
psi
velocity in feet / second
gallons per minute
area in square inches
inside diameter of pipe in inches
32.16 ft. /sec. /sec.
head in feet
horsepower
Specific gravity*
pounds per square inch
=
=
=
=
=
=
=
=
=
AFFINITY LAW
USEFUL FORMULAS
Q2Q1
n2n1
= H2H1
n2n1
=, ( )2 P2P1
n2n1
=, ( )3
* These equivalents are based on a specific gravity of 1 for water at 62 F for English units and a specific gravity of 1 for water at 15 C for metric units. They can be used, with little error, for cold water of any temperature between 32 F and 80 F.
3
134 135
CALCULATING PUMP HEAD
Reference
HAZEN-WILLIAMS FORMULA
CALCULATING FRICTION LOSSES
H= I f = I . L
Hf =
10.666Q1.85
C1.85 . D4.87
10.666Q1.85 .LC1.85 . D4.87
Where :I : Hydraulic gradientQ : Quantity of flow (m3/s)C : Flow velocity coefficient (Refer to Table)
Tar-epoxy coated pipes: 130Mortar lined pipes: 130Vinyl chloride pipes: 150
D : Pipe diameter (m)L : Total length of pipeline (m)
Where :Hatm : atmospheric pressure (m)NPSHr : net positive suction head required by the pump (m)Hf : friction loss in suction line and fittings (m)Hv : liquid vapour pressure (m)Hs : safety margin allowance (m)
Table Flow velocity Coefficients for Various Type Pipes (For Straight Pipe)
Pipe type (inside surface)
Flow velocity coefficientMax. value Min. value Standard value
Cast iron pipe (without coating)*
Steel pipe (without coating)*
Coal tar coated pipe (cast iron)*
Tar-epoxy coated pipe (steel)**
Mortar lined pipe (steel, cast iron)
Centrifugal reinforced concrete pipe
Rolling press reinforced concrete pipe
Pressed concrete pipe
Asbestos cement pipe
Hard vinyl chloride pipe***
Hard polyethylene pipe***
Reinforced plastics pipe***
150 80 100
150 90 100
145 80 100___ ___ 130
150 120 130
140 120 130
140 120 130
140 120 130
160 140 140
160 140 150
170 130 150
160 ___ 150
This formula is applied where flows are in transitional range (of roughness/smoothness), and is commonly applicable to the calculation of loss heads for relatively long pipelines such as irrigation water lifting, city water supply, or sewage water pipelines.
CALCULATING MAXIMUM SUCTION LIFT
For mortar lined pipe : c = 110For coated steel pipe : c = 110 (bends included)For vinyl chloride pipe : c = 110
Suction Lift (m) = Hatm - NPSHr - Hf - Hv - Hs
Notes :* Changes due to time passage have been taken
into account.** The coating method should conform to
JWWAK-115-1974, and preferably the coating thickness should be 0.5mm or more. In addition, where adequate management/control is expected to be difficult for coating work at site, this should not be applied.
*** C = 150 should be applied to pipes with a diameter of 150mm or smaller.
The values listed on the table do not include loss heads due to pipe shapes, such as bends, expansion, reduction in diameters, etc. Therefore, when obtaining the total loss heads, such individual losses as described above should be added to the straight line loss. However, the following values may be used to calculate approximate loss values if bends or other shape changes cannot be accurately estimated.
4
5
136
Recommended outlet diameter
Recommended inlet diameter
Pressure drops (Pc) in metres, water column, for every hundred metres of new piping in cast iron.Speed of the liquid in the piping in metres/second (V m/s).
CAPACITY
m3/h
3
6
9
12
15
18
21
24
27
30
36
42
48
54
60
75
90
105
120
135
150
165
180
210
240
270
300
360
420
480
540
600
660
720
780
840
900
960
1020
1080
1140
1200
Pc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/sPc %Vm/s
25 32 40 50 60 70 80 90 100 125 150 175 200 225 250 275 300 350 400 450 500 600 700 800 900 1000
17 6 1.6 0.54 0.25 0.13 0.06 0.03 0.021.70 1.03 0.67 0.43 0.29 0.22 0.16 0.13 0.10
24 6 2 0.9 0.43 0.21 0.13 0.08 0.0261.70 1.03 0.67 0.43 0.29 0.22 0.16 0.13 0.10
12.5 4.3 1.8 0.9 0.46 0.25 0.15 0.06 2.08 1.32 0.89 0.65 0.5 0.39 0.32 0.20 20 7 32 1.5 0.75 0.44 0.25 0.09 0.032.76 1.76 1.19 0.88 0.67 0.53 0.43 0.27 0.18
22 8.8 4.2 2.2 1.3 0.75 0.26 0.1 0.053.35 2.08 1.54 1.17 0.93 0.75 0.48 0.32 0.24
12 5.2 2.4 1.25 0.7 0.42 0.15 0.0 2.2 1.49 1.1 0.87 0.66 0.54 0.34 0. 24 17 7 3.5 1.7 1 0.6 0.2 0.08 2.64 1.78 1.3 1 0.78 0.64 0.4 0.28
12 5,7 3 1.7 1 0.36 0.14 0.07 2.38 1.76 1.34 1.06 0.86 0.54 0.36 0.28 14 7 3,5 2 1.25 0.42 0.17 0.08 2.7 1.97 1.45 1.17 0.96 0.6 0.42 0.31 17 8.2 4.2 2.5 1.5 0.5 0.2 0.09 2.98 2.2 1.74 1.32 1.08 0.68 0.48 0.34
16 8.5 4,5 2.7 0.85 0.33 0.18 0.08 3.07 2.34 1.85 1.5 0.96 0.66 0.48 0. 37 21 10 6 3,6 1.2 0.45 0.22 0.12 0.063.51 2.68 2.12 1.72 1.08 0.72 0.56 0.43 0.34 25 13.5 7.6 4.5 1.5 0.55 0.28 0.14 0.083.94 3 2.34 1.92 1.2 0.84 0.63 0.48 0.38
16 9 5.5 1.8 0.7 0.33 0.17 0.13.32 2.64 2.16 1.36 0.96 0.68 0.53 0.42
20 12.5 3.8 1.45 0.74 0.36 0.2 0.14 0.083.97 3.24 2.04 1.44 1.02 0.8 0.63 0.51 0.42 26 16.5 5.3 1.95 0.9 0.47 0.27 0.16 0.1 4.6 3.74 2.41 1.68 1.22 0.93 0.74 0.59 0.49
21.5 6.9 2.6 1.2 0.61 0.36 0.2 0.14 0.08 4.31 2.72 1.93 1.35 1.06 0.84 0.68 0.56 0.47 26 9 3.3 1.5 0.76 0.45 0.25 0.17 0.1 4.81 1.07 2.13 1.56 1.19 0.95 0.76 0.63 0.53
11 4 1.9 0.95 0.55 0.3 0.21 0.12 0.06 3.44 2.36 1.74 1.34 1.05 0.86 0.70 0.59 0.43 13 4.7 2.2 1.13 0.65 0.37 0.24 0.15 0.08 3.75 2.61 1.91 1.46 1.15 0.94 0.77 0.65 0.48 15.2 5.5 2.6 1.3 0.76 0.43 0.29 0.18 0.09 4.09 2.83 2.08 1.59 1.26 1.02 0.84 0.71 0.52 21 7.4 3.5 1.8 1.1 0.6 0.37 0.24 0.12 0.06 4.70 3.32 2.43 1.86 1.49 1.19 0.98 0.82 0.61 0.47
9.4 4.3 2.3 1.3 0.75 0.48 0.3 0.15 0.08 3.78 2.77 2.12 1.68 1.36 1.12 0.95 0.69 0.53 12 5.5 2.8 1.62 0.9 0.58 0.35 0.18 0.09 4.26 3.13 2.39 1.90 1.53 1.26 1.07 0.78 0.59 14 7.5 3.4 2 1.1 0.74 0.46 0.22 0.11 0.07 4.75 3.47 2.66 2.10 1.71 1.40 1.18 0.86 0.67 0.53
9 4.7 2.8 1.6 1 0.65 0.32 0.16 0.09 0.05 4.15 3.17 2.53 2.04 1.68 1.41 1.04 0.79 0.63 0.51
8.5 4.9 2.9 1.9 1.2 0.6 0.3 0.17 0.09 0.04 4.24 3.36 2.72 2.24 1.90 1.38 1.06 0.84 0.69 0.47 11 6.5 3.7 2.35 1.52 0.75 0.38 0.22 0.12 0.05 4.78 3.80 3.06 2.52 2.13 1.56 1.19 0.94 0.76 0.53
9 5.2 3.3 2.1 1.1 0.54 0.3 0.16 0.06 0.03 4.61 3.76 3.07 2.59 1.89 1.45 0.15 0.93 0.65 0.48 10 6 3.8 2.5 1.3 0.62 0.35 0.19 0.075 0.035 5.05 4.08 3.37 2.84 2.08 1.65 1.26 1.02 0,71 0.52
7.3 4.5 3 1.5 0.75 0.42 0.23 0.08 0.04 4.43 3.65 3.08 2.26 1.73 1.36 1.11 0.77 0.56 8 5.4 3.4 1.7 0.85 0.48 0.26 0.1 0.047 4.76 3.95 3.31 2.43 1.86 1.47 1.19 0.83 0.61 9 5.8 3.75 1.9 0.96 0.53 0.29 0.11 0.053 5.1 4.22 3.54 2.60 2.00 1.57 1.27 0.88 0.65
6.5 4.3 2.1 1.1 0.6 0.32 0.12 0.06 4.49 3.78 2.77 2.13 1.68 1.36 0.95 0.70 7.2 4.6 2.45 1.2 0.67 0.35 0.14 0.065 0.033 4.76 4.01 2.94 2.26 1.78 1.44 1.00 0.77 0.54
5.4 2.8 1.4 0.78 0.43 0.16 0.073 0.037 4.26 3.12 2.38 1.86 1.53 1.06 0.78 0.57 6 3.2 1.53 0.86 0.46 0.175 0.08 0.043 0.037 4.49 3.29 2.53 1.99 1.65 1.12 0.84 0.61 0.52 6.5 3.4 1.7 0.93 0.5 0.19 0.09 0.046 0.04 0.025 4.72 3.45 2.68 2.12 1.72 1.23 0.88 0.63 0.54 0.4
12.2 7.4 4.3 2.7 1.7 0.9 0.45 0.25 0.13 0.055 0.024 5.30 4.20 3.40 2.81 2.36 1.73 1.34 1.06 0.86 0.61 0.44
1.6 6.2 3.5 2 1.3 0.82 0.41 0.21 0.12 0.07 0.03 4.86 3.72 2.94 2.37 1.96 1.64 1.22 0.94 0.76 0.59 0.41
24 14 8 2.76 1 0.49 0.24 0.14 0.084.17 3.31 2.68 1.72 1.18 0.87 0.67 0.53 0.43
25 12 6.3 3.5 2 0.75 0.3 0.14 0.07 3.58 2.63 2 1.58 1.28 0.82 0.57 0.42 0.32
INSIDE DIAMETER (mm)
If is possible to approximate the pressure losses caused
by the accessories with the following comparisons:
Bottom valve: like 15 m piping
Check valve: like 10 m piping
On/off valve: like 5 m piping
Bends and elbows: like 5 m piping
For piping other than new piping in cast iron, multiply
the figures in the table by the following coefficients:
67,0:leets sselniatS
67,0:CVP
08,0:yalC
08,0:leets delloR
71,1:leets dezinavlaG
Slightly rusted pipes: 2,10
Highly encrusted rusted pipes: 3,60
PRESSURE DROP TABLE
Reference
134 135
NET POSITIVE SUCTION HEAD (NPSH)
Reference
Net Positive Suction Head (NPSHR)NPSHR is dependent upon the pump design and is determined by the pump manufacturer. NPSHR is an important value which greatly contributes to the successful operation of a centrifugal pump. It is the amount of positive head in metre of liquid absolute required at the pump suction to prevent vaporization or cavitation of the fluid. NPSHR values usually vary with pump capacity and are based on clear water with a specific gravity of 1.0.
Net Positive Suction Head Available (NPSHA)NPSHA is dependent upon the system in which the pump operates. NPSHA is the amount of head or pressure that is available to prevent vaporization or cavitation of the fluid in the system. It is the amount of head available above the vapor pressure of the liquid at a specified temperature and is measured in metre of liquid absolute .
NPSHA = (P1 - Pv) x 2.31Sp. Gr.
+ Z1 - Hfs
WhereP1 : Absolute pressure on liquid surface in psia.
Absolute pressure is equal to gauge reading plus atmospheric pressure.Three common examples are:1. Open tank - No gage reading so absolute pressure equals atmospheric pressure or
14.7 psia at sea level.2. Closed tank under pressure - Add gage reading in psi to atmospheric pressure to
get total absolute pressure.3. Closed tank under vacuum - Subtract vacuum reading in inches of mercury from
atmospheric pressure in inches of mercury (30 inches at sea level) and convert to psia by multiplying by .49.
P1 = (30 - Vacuum) x .49
Pv : Vapor pressure of liquid in psia at pump temperature.Z1 : Height of liquid surface above pump suction, measured in ft. If surface is below pump,
use minus sign.Hfs : Friction loss in ft of liquid in suction pipe including entrance loss from tank to pipe,
and losses in all valves, elbows and other fittings.Sp.Gr. : Specific gravity of liquid being handled.
NPSHA vs. NPSHRTo prevent vaporization or cavitation of the liquid in the suction side of the pump and to ensure rated pumpperformance, NPSHA must be greater or equal to the NPSHR.
That is : NPSHA NPSHR
12