Reference
CONVERSION TABLE
131
Reference
SI UNIT
TRANSLATION TO UNIT (SI)
Item
Existing Unit (SI Unit)
SI Unit
Force
1kgf ( = 9.80665N )
1N ( = 0.101972kgf )
Pressure
1kgf/cm3 ( = 0.0980665MPa )
1mAq ( = 9.80665kPa )
1mmHg ( = 0.133322kPa )
1MPa ( = 10.1972kgf/cm2 )
1kPa ( = 0.101972mAq)
1kPa ( = 7.50062mmHg )
Mass
Mass: 1kg ( =1kg )
Mass: 1kg ( =1kg )
Speed
Revolution speed: 1r.p.m.( =1min-1 )
Revolution speed: 1min-1( =1r.p.m. )
Viscosity
1cP ( = 1mPa.S )
1mPa.S ( = 1cP )
Dynamic Viscocity
1cSt ( = 1mm2/s )
1mm2/s ( = 1cSt )
Specific heat
1kcal/kg. c ( = 4.18605kJ/(kg.K) )
1kJ/(kg. K) ( = 0.238889kcal / (kg. c) )
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 )
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)
Work energy
Power
ELECTRICAL DATA
TO DETERMINE: AMPERES, HORSEPOWER, KILOWATTS, AND KVA
To find
Amperes when
horsepower is known
Amperes when
kilowatt is known
Direct current
Single-phase
H.P. x 746
E x %Eff.
H.P. x 746
E x %Eff. x P.F.
H.P. x 746
1.73 x E x %Eff. x P.F.
K.W. x 1000
E
K.W. x 1000
E x P.F.
K.W. x 1000
1.73 x E x P.F.
K.W. x 1000
E
K.W. x 1000
1.73 x E
I x E x P.F.
I x E x x 1.73 x P.F.
I xE
I x E x 1.73
I x E x %Eff. x P.F.
I x E x 1.73 x %Eff.x P.F.
Amperes when
KVA is known
Kilowatts
I xE
1000
1000
KVA
1000
Horsepower output
Where:
A:
E:
%Eff. :
P.F. :
Amperes
Volts
per cent efficiency
Power Factor
Three-phase
I x E x %Eff.
746
746
K.W. :
KVA :
H.P. :
I :
Kilowatts
Kilo-volt-amperes
Horsepower
Current
132
1000
1000
746
Reference
COMMONLY USE PUMP FORMULAS
HEAD AND PRESSURE
Head (m) =
pressure (kPa)
9.8 x specific gravity
or
pressure (bar) x 10.2
specific gravity
; Head (ft) =
pressure (psi) x 2.31
specific gravity
Head (m) = Head (ft) x 0.305
Head (ft) = Head (m) x 3.28
BRAKE HORSEPOWER OR BRAKE KILOWATT
To determine the horsepower or kilowatt required, the following formulas can be used:
a) Brake horsepower =
Total Head (ft) x IGPM x Sp. Gr.
pump efficiency % x 3300
b) Brake horsepower =
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
c) Brake Kilowatt =
AFFINITY LAW
Q2
Q1
=
n2
n1
,
H2
H1
=
( nn )
2
2
1
,
P2
P1
=
( nn )
2
3
Where n = Speed, Q = Flow, H = Head, P = Power
1
USEFUL FORMULAS
ABBREVIATIONS
FORMULAS
V=
GPM x 0.321
F
=
GPM x 0.409
(I.D.)2
2
V = 2 gH
H=
H=
2.31 x psi
Sp. Gr.*
1.134 x inches of mercury
Sp. Gr.*
Sp. Gr.*=
141.5
131.5 + AP 1 (Baume)
V
= velocity in feet / second
GPM
= gallons per minute
F
= area in square inches
I.D.
= inside diameter of pipe in inches
g
= 32.16 ft. /sec. /sec.
H
= head in feet
HP
= horsepower
Sp. Gr.
= Specific gravity*
psi
= pounds per square inch
* 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.
133
Reference
CALCULATING PUMP HEAD
CALCULATING FRICTION LOSSES
HAZEN-WILLIAMS FORMULA
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.
1.85
10.666Q
1.85
4.87
C .D
I=
Hf =
Hf
Where :
I
: Hydraulic gradient
Q : Quantity of flow (m3/s)
C : Flow velocity coefficient (Refer to Table)
Tar-epoxy coated pipes: 130
Mortar lined pipes: 130
Vinyl chloride pipes: 150
D : Pipe diameter (m)
L : Total length of pipeline (m)
=I . L
1.85
10.666Q .L
1.85
4.87
C .D
Table Flow velocity Coefficients for
Various Type Pipes (For Straight Pipe)
Pipe type
(inside surface)
Flow velocity coefficient
Max. value
Min. value Standard value
Notes :
*
Changes due to time passage have been taken
into account.
** The coating method should conform to
Cast iron pipe (without coating)*
150
80
100
JWWAK-115-1974, and preferably the coating
Steel pipe (without coating)*
150
90
100
In addition, where adequate management/control
Coal tar coated pipe (cast iron)*
145
80
100
Tar-epoxy coated pipe (steel)**
___
___
130
Mortar lined pipe (steel, cast iron)
150
120
130
Centrifugal reinforced concrete pipe
140
120
130
The values listed on the table do not include loss heads
Rolling press reinforced concrete pipe
140
120
130
in diameters, etc. Therefore, when obtaining the total loss
Pressed concrete pipe
140
120
130
Asbestos cement pipe
160
140
140
values may be used to calculate approximate loss values
Hard vinyl chloride pipe***
160
140
150
estimated.
Hard polyethylene pipe***
170
130
150
160
___
150
Reinforced plastics pipe***
thickness should be 0.5mm or more.
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.
due to pipe shapes, such as bends, expansion, reduction
heads, such individual losses as described above should
be added to the straight line loss. However, the following
if bends or other shape changes cannot be accurately
For mortar lined pipe : c = 110
For coated steel pipe : c = 110
For vinyl chloride pipe : c = 110
CALCULATING MAXIMUM SUCTION LIFT
Suction Lift (m) =
Where :
Hatm
NPSHr
Hf
Hv
Hs
:
:
:
:
:
Hatm - NPSHr - Hf - Hv - Hs
atmospheric pressure (m)
net positive suction head required by the pump (m)
friction loss in suction line and fittings (m)
liquid vapour pressure (m)
safety margin allowance (m)
134
(bends included)
Reference
NET POSITIVE SUCTION HEAD (NPSH)
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 2.31
Sp. Gr.
+ Z1 - Hfs
Where
: Absolute pressure on liquid surface in psia.
P1
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
Z1
: Vapor pressure of liquid in psia at pump temperature.
: Height of liquid surface above pump suction, measured in ft. If surface is below pump,
use minus sign.
: Friction loss in ft of liquid in suction pipe including entrance loss from tank to pipe,
Hfs
and losses in all valves, elbows and other fittings.
Sp.Gr. : Specific gravity of liquid being handled.
NPSHA vs. NPSHR
To prevent vaporization or cavitation of the liquid in the suction side of the pump and to ensure rated pump
performance, NPSHA must be greater or equal to the NPSHR.
That is : NPSHA
NPSHR
135
Reference
PRESSURE DROP TABLE
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).
INSIDE DIAMETER (mm)
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
25
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
Pc %
Vm/s
32
40
17
6
1.6
1.70 1.03 0.67
24
6
1.70 1.03
12.5
2.08
20
2.76
50
60
70
80
90
0.54
0.43
2
0.67
4.3
1.32
7
1.76
12
2.2
17
2.64
22
3.35
0.25
0.29
0.9
0.43
1.8
0.89
32
1.19
5.2
1.49
7
1.78
8.8
2.08
12
2.38
14
2.7
17
2.98
25
3.58
0.13
0.22
0.43
0.29
0.9
0.65
1.5
0.88
2.4
1.1
3.5
1.3
4.2
1.54
5,7
1.76
7
1.97
8.2
2.2
12
2.63
16
3.07
21
3.51
25
3.94
0.06
0.16
0.21
0.22
0.46
0.5
0.75
0.67
1.25
0.87
1.7
1
2.2
1.17
3
1.34
3,5
1.45
4.2
1.74
6.3
2
8.5
2.34
10
2.68
13.5
3
16
3.32
24
4.17
0.03
0.13
0.13
0.16
0.25
0.39
0.44
0.53
0.7
0.66
1
0.78
1.3
0.93
1.7
1.06
2
1.17
2.5
1.32
3.5
1.58
4,5
1.85
6
2.12
7.6
2.34
9
2.64
14
3.31
20
3.97
26
4.6
100
125 150
0.02
0.10
0.08 0.026
0.13 0.10
0.15 0.06
0.32 0.20
0.25 0.09 0.03
0.43 0.27 0.18
0.42 0.15 0.0
0.54 0.34 0. 24
0.6 0.2 0.08
0.64 0.4 0.28
0.75 0.26 0.1
0.75 0.48 0.32
1 0.36 0.14
0.86 0.54 0.36
1.25 0.42 0.17
0.96 0.6 0.42
1.5 0.5 0.2
1.08 0.68 0.48
2 0.75 0.3
1.28 0.82 0.57
2.7 0.85 0.33
1.5 0.96 0.66
3,6 1.2 0.45
1.72 1.08 0.72
4.5 1.5 0.55
1.92 1.2 0.84
5.5 1.8 0.7
2.16 1.36 0.96
8 2.76 1
2.68 1.72 1.18
12.5 3.8 1.45
3.24 2.04 1.44
16.5 5.3 1.95
3.74 2.41 1.68
21.5 6.9 2.6
4.31 2.72 1.93
26
9
3.3
4.81 1.07 2.13
11
4
3.44 2.36
13 4.7
3.75 2.61
15.2 5.5
4.09 2.83
21 7.4
4.70 3.32
9.4
3.78
12
4.26
14
4.75
For piping other than new piping in cast iron, multiply
the figures in the table by the following coefficients:
Stainless steel:
0,76
PVC:
0,76
Clay:
0,80
Rolled steel:
0,80
Galvanized steel:
1,17
Slightly rusted pipes:
2,10
Highly encrusted rusted pipes:
3,60
Recommended outlet diameter
Recommended inlet diameter
136
175
200 225
250 275
300
350 400
450 500
600 700
800
900 1000
If is possible to approximate the pressure losses caused
by the accessories with the following comparisons:
0.05
0.24
0.07
0.28
0.08
0.31
0.09
0.34
0.14
0.42
0.18
0.48
0.22
0.56
0.28
0.63
0.33
0.68
0.49
0.87
0.74
1.02
0.9
1.22
1.2
1.35
1.5
1.56
1.9
1.74
2.2
1.91
2.6
2.08
3.5
2.43
4.3
2.77
5.5
3.13
7.5
3.47
9
4.15
1.6
4.86
0.07
0.32
0.08
0. 37
0.12 0.06
0.43 0.34
0.14 0.08
0.48 0.38
0.17 0.1
0.53 0.42
0.24 0.14
0.67 0.53
0.36 0.2
0.8 0.63
0.47 0.27
0.93 0.74
0.61 0.36
1.06 0.84
0.76 0.45
1.19 0.95
0.95 0.55
1.34 1.05
1.13 0.65
1.46 1.15
1.3 0.76
1.59 1.26
1.8 1.1
1.86 1.49
2.3 1.3
2.12 1.68
2.8 1.62
2.39 1.90
3.4
2
2.66 2.10
4.7 2.8
3.17 2.53
6.2 3.5
3.72 2.94
8.5 4.9
4.24 3.36
11 6.5
4.78 3.80
12.2 7.4
5.30 4.20
9
4.61
10
5.05
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
0.08
0.43
0.14
0.51
0.16
0.59
0.2
0.68
0.25
0.76
0.3
0.86
0.37
0.94
0.43
1.02
0.6
1.19
0.75
1.36
0.9
1.53
1.1
1.71
1.6
2.04
2
2.37
2.9
2.72
3.7
3.06
4.3
3.40
5.2
3.76
6
4.08
7.3
4.43
8
4.76
9
5.1
0.08
0.42
0.1
0.49
0.14
0.56
0.17
0.63
0.21
0.70
0.24
0.77
0.29
0.84
0.37
0.98
0.48
1.12
0.58
1.26
0.74
1.40
1
1.68
1.3
1.96
1.9
2.24
2.35
2.52
2.7
2.81
3.3
3.07
3.8
3.37
4.5
3.65
5.4
3.95
5.8
4.22
6.5
4.49
7.2
4.76
0.08
0.47
0.1
0.53
0.12
0.59
0.15
0.65
0.18
0.71
0.24
0.82
0.3
0.95
0.35
1.07
0.46
1.18
0.65
1.41
0.82
1.64
1.2
1.90
1.52
2.13
1.7
2.36
2.1
2.59
2.5
2.84
3
3.08
3.4
3.31
3.75
3.54
4.3
3.78
4.6
4.01
5.4
4.26
6
4.49
6.5
4.72
0.06
0.43
0.08
0.48
0.09
0.52
0.12
0.61
0.15
0.69
0.18
0.78
0.22
0.86
0.32
1.04
0.41
1.22
0.6
1.38
0.75
1.56
0.9
1.73
1.1
1.89
1.3
2.08
1.5
2.26
1.7
2.43
1.9
2.60
2.1
2.77
2.45
2.94
2.8
3.12
3.2
3.29
3.4
3.45
0.06
0.47
0.08
0.53
0.09
0.59
0.11
0.67
0.16
0.79
0.21
0.94
0.3
1.06
0.38
1.19
0.45
1.34
0.54
1.45
0.62
1.65
0.75
1.73
0.85
1.86
0.96
2.00
1.1
2.13
1.2
2.26
1.4
2.38
1.53
2.53
1.7
2.68
0.07
0.53
0.09
0.63
0.12
0.76
0.17
0.84
0.22
0.94
0.25
1.06
0.3
0.15
0.35
1.26
0.42
1.36
0.48
1.47
0.53
1.57
0.6
1.68
0.67
1.78
0.78
1.86
0.86
1.99
0.93
2.12
0.05
0.51
0.07 0.03
0.59 0.41
0.09 0.04
0.69 0.47
0.12 0.05
0.76 0.53
0.13 0.055 0.024
0.86 0.61 0.44
0.16 0.06 0.03
0.93 0.65 0.48
0.19 0.075 0.035
1.02 0,71 0.52
0.23 0.08 0.04
1.11 0.77 0.56
0.26 0.1 0.047
1.19 0.83 0.61
0.29 0.11 0.053
1.27 0.88 0.65
0.32 0.12 0.06
1.36 0.95 0.70
0.35 0.14 0.065 0.033
1.44 1.00 0.77 0.54
0.43 0.16 0.073 0.037
1.53 1.06 0.78 0.57
0.46 0.175 0.08 0.043 0.037
1.65 1.12 0.84 0.61 0.52
0.5 0.19 0.09 0.046 0.04 0.025
1.72 1.23 0.88 0.63 0.54 0.4