CW Pipe Material
CW Pipe Material
CW Pipe Material
Introduction
This spreadsheet can be used to calculate pressure drops in liquid lines, taking account fittings (such as bends,
valves and other equipment items).
It is recommended that the user first reads the 'How to Use These Calculation' worksheet before starting a
calculation.
Revision
Rev. 1 Initial issue 12-Oct-09
Rev. 1A Cosmetic changes only (spell checking & revised disclaimer) 15-Dec-09
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held responsible
for its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids Revision 1A
The spreadsheet has four columns which link from one to the next. This can be used to break a piping system
down into a number of component sections, if needed.
Although these items are not strictly necessary, they help describe the calculation - this can be
invaluable it is to be checked by another engineer. The 'To' and 'From' Sections are particularly useful
if the calculation is split over several columns.
2.4.1 Viscosity
The user inputs the liquid viscosity in Centipoise (Cp). It should be noted that viscosity
changes with temperature - thus the user must ensure that the viscosity value entered
must be at the correct temperature.
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held
responsible for its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids Revision 1A
2.4.2 Density
The user inputs the liquid density in kg/m3. As with viscosity, the density changes with
temperature - thus the user must ensure that the density value entered must be at the
correct temperature.
By entering the nominal diameter and schedule, the spreadsheet automatically retrieves the
correct internal diameter of the pipe. It should be noted that not all combinations of nominal
diameter and schedule are permissible; if the wrong combination is selected the spreadsheet
displays an error. A list of standard pipe sizes can be found by clicking on the link below:
On occasions, the user may wish to calculate a pressure drop for a non-standard pipe. In this
case, the user can simply over write the internal diameter cell on the spreadsheet (either in
inches or mm).
2.6 Flowrates
The user enters the required liquid flowrate in kg per hour. The spreadsheet then calculates the
volumetric flowrate (in m3/s), the line velocity (m/s) and the pressure drop per unit length.
(in bar/100m).
The calculated line velocity and pressure drop per unit length can be used to assess whether the pipe
diameter is reasonable for the required flowrate.
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held
responsible for its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids Revision 1A
- For increases in elevation - i.e. the end of the pipe is higher than the inlet, the
change in elevation should be entered as a positive number (this will result in a
larger total pressure drop than if the pipe had been level.
- For decreases in elevation - i.e. the end of the pipe is lower than the inlet, the
change in elevation should be entered as a negative number (this will result in a
smaller total pressure drop than if the pipe had been level.
2.9 Summary
The summary section provides a summary of the calculation results, namely:
These three values are used to calculate the total pressure drop in the line and the downstream pressure.
However, for more complex piping systems, the other calculation columns can be used to build up a piping network
This can be very useful if, for example, the user needs to determine pressure drop in distribution systems.
To make this easier, the downstream pressure of the first column is used as the upstream pressure of the second
column and so on. The physical property and flowrate data entered in the first column is copied across to the
other three columns to make it easier to set up a network - these values can be overwritten, if required.
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held
responsible for its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids
Revision 1A
See 'How to use these Calculation' worksheet for notes on its use.
Calculation Title:
From:
To:
Pressure Data
Upstream Pressure bar (g) 1.02 0.85 0.85 0.85
Physical Property Data
Viscosity Cp 1.0 1.0 1.0 1.0
Liquid Density kg/m3 1000 1000 1000 1000
Pipe Data
Nominal Line Diameter inches 1.50 0.50 3.00 3.00
Pipe Schedule 10S 40 40 40
Pipe Material Type Steel (New) Steel (New) Steel (New) Steel (New)
Internal Diameter inches 1.68 0.62 3.07 3.07
Internal Diameter mm 42.7 15.8 77.9 77.9
Flowrates
Mass Flow kg/h 2,160 2,160 2,160 2,160
Volumetric Flow m3/h 2.16 2.16 2.16 2.16
Line Velocity m/s 0.42 3.06 0.13 0.13
Pres drop per 100m bar/100m 0.060 8.696 0.003 0.003
Line Losses
Pipe Length m 280 0 0 0
Number of 90o bends 0 0 0 0
Number of valves 0 0 0 0
Check Valves 0 0 0 0
T-Piece straight run 0 0 0 0
T-Piece as elbow 0 0 0 0
Other Pressure Drops
Elevation Increase m 0.0 0.0 0.0 0.0
Other Pressure Drops bar 0.00 0.00 0.00 0.00
Summary
Line Losses bar 0.17 0.00 0.00 0.00
Static Pressure Gain bar 0.00 0.00 0.00 0.00
Other Pressure Drops bar 0.00 0.00 0.00 0.00
Total Pressure Drop bar 0.17 0.00 0.00 0.00
Downstream Pressure bar (g) 0.85 0.85 0.85 0.85
Notes
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held responsible
for its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids
CALCULATION THEORY
1.0 Introduction
This spreadsheet can be used to calculate pressure drops in pipelines, taking account of inline fittings (such as
bends, valves and other equipment items. To use the spreadsheet, follow the instructions given in the "How to
Use this Spreadsheet" Worksheet.
This worksheet presents the equations and algorithms used in the calculation and discusses elements of fluid flow
theory.
The internal diameter, d, (in metres) is used to calculate the cross-sectional flow area, A, (in square metres)
using Equation 1:
2
pd
A = Equation (1)
4
m
u = Equation (2)
rA
Where:
m - Mass flowrate (in kg/s)
r - Liquid density (in kg/m3)
A - Cross-sectional flow area (in m2)
rud
Re = Equation (3)
m
Where
m - Viscosity (in Pa.s)
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held responsible for
its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids
2.4 Calculation of the Pipe Relative Roughness
The pressure drop from flow down a pipe - at least in turbulent flow - is affected by the roughness of the
pipe surface. Obviously, the pipe roughness is determined by the pipe materials of construction. The
spreadsheet provides typical pipe roughness values for a range of materials i.e.
The effect of pipe roughness becomes less important as the pipe diameter increases, thus the spreadsheet
calculates the pipe roughness relative to the pipe diameter using Equation 4.
e Equation (4)
Pipe Relative Roughness = d
Where:
e - Pipe roughness (in m)
d - Pipe internal diameter (in m)
The Fanning Friction Factor can be determined from Charts (Moody Diagram) or by using an empirical
equation. A number of Friction Factor Correlations are available in the literature, the one used in this
spreadsheet is the Churchill Correlation see Equations 5, 6 and 7.
/12
1
12
8 1
fFanning = 2 x + (A + B)1.5 Equation (5)
Re
Where
16
1
A = 2.457 x ln 7 0.9 e Equation (6)
Re + 0.27 x d
and
16
B = 37530
Re Equation (7)
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held responsible for
its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids
The Churchill Correlation is used as it is applicable to both laminar and turbulent flow - this is not the case
all correlations.
It should be noted that the Fanning Friction Factor is NOT the same as other Friction Factors: i.e. Darcy and
Moody
2.6 Calculation of the Pressure Drop per Unit Length of Straight Pipe
The pressure loss as a liquid flows down a straight length of pipe is given by the Darcy Equation. This
is expressed in Equation 8 below.
Where
DPPipe - Pipe line pressure drop (in Pa)
LPipe - Pipe length (in m)
It should be noted that the form of the equation presented via this link uses the Darcy Friction Factor, which
is four times larger than the Fanning Friction Factor. Equation 8 can be adapted to calculate the Pressure
per 100 metres by setting LPipe to 100 and converting from Pa to Bar - see Equation 9.
metres
4 fFanning x 100 r.u2
Bar per 100m = d x 10 5 2 Equation (9)
Pa / bar
r.u2
DP = K 2 Equation (10)
Fittings
N.B. It can be seen from Equations 8 and 10 that the Resistance Coefficient equates to (4f FanningL)/d for
a straight length of pipe. The spreadsheet uses the following Resistance Coefficients for different pipe
fittings
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held responsible for
its use. As with all areas of process engineering, calculations should be checked by a competent engineer.
Standard Line Sizing Spreadsheet For Liquids
Obviously, these values are approximate as K is affected by factors such as radius of the bend and the
valve design. A detailed list of Resistance Coefficients for different pipe fittings is given in Cranes' Flow
of Fluids book - see link below.
The Line Losses value given in the spreadsheet is the sum of the DPPipe and DPFittings.
r x 9.81 x Dh
DP = Equation (11)
Elevatio
n 105
Pa / bar
The total pressure drop is the sum of the line losses, DPElevation and other pressure drop (added manually
by the user).
Disclaimer: This calculation provides an estimate for estimating pressure drops in liquid pipelines. We cannot be held responsible for
its use. As with all areas of process engineering, calculations should be checked by a competent engineer.