Introduction www.myChemE.comStandard Line Sizing Spreadsheet For GasesIntroductionThis spreadsheet can be used to calculate pressure drops in gas and vapour lines, taking account fittings (suchas bends, valves and other equipment items).The spreadsheet is split into the following sections-A "How to Use This Calculation" Worksheet-The Pressure Drop Calculation Worksheet itself - marked "Calculation"-A Theory Worksheet which presents the equations used in the calculation.It is recommended that the user first reads the 'How to Use These Calculation' worksheet before starting acalculation.RevisionRev. 1Initial issue16-Dec-09Disclaimer: This calculation provides an estimate for estimating pressure drops in gas and vapour pipelines. We cannot be heldresponsible for its use. As with all areas of process engineering, calculations should be checked by a competent engineer.

54.5 WCf P1 Gf (Y 0.148 Y3)Cv =Y =www.myChemE.com

Calculationwww.myChemE.comStandard Line Sizing Spreadsheet For GasesRevision 1See 'How to use these Calculation' worksheet for notes on its use.Calculation Title:From:To:Pressure & Temperature DataUpstream Pressurebar (g)7.006.676.676.67TemperaturedegC171171171171Gas Properties DataMolecular Weightkg/kmol18.018.0018.0018.00Compressibility, Z0.90.90.90.9ViscosityCp0.0200.0200.0200.020Gas Densitykg/m34.3904.2094.2094.209Pipe DataNominal Line Diameterinches1.500.750.750.75Pipe Schedule80404040Pipe Material TypeSteel (New)Steel (New)Steel (New)Steel (New)Internal Diameterinches1.500.820.820.82Internal Diametermm38.120.920.920.9FlowratesMass Flowkg/h222222222222Volumetric Flowm3/h50.5752.7552.7552.75Line Velocitym/s12.342.642.642.6Pres drop per 100mbar/100m0.2044.6654.6654.665Line LossesPipe Lengthm120000Number of 90o bends25000Number of valves5000Check Valves0000T-Piece straight run0000T-Piece as elbow0000Other Pressure DropsOther Pressure Dropsbar0.000.000.000.00SummaryTotal Pressure Dropbar0.330.000.000.00Downstream Pressurebar (g)6.676.676.676.67NotesThis spreadsheet calcluates pressure drop based on the upstream gas conditions. Consequently, the calculatedpressure drop will be an underestimate. To obtain reasonable accuracy ensure that the total pressure drop isnot more than 10% of the upstream pressure in each column. See "How to Use This Calculation" for detailsDisclaimer: This calculation provides an estimate for estimating pressure drops in gas and vapour pipelines. We cannot be heldresponsible for its use. As with all areas of process engineering, calculations should be checked by a competent engineer.Pressure Drop CorrelationPipe X-Sectional Areasq.m1.140E-033.440E-043.440E-043.440E-04Reynolds Number, Re103,040187,573187,573187,573Pipe roughness, emm0.0500.0500.0500.050e/d0.0013123360.00238896110.00238896110.0023889611Churchill CorrelationA192263305870332620000914889262844484000009148892628444840000091488926284448400000B0.0000000959000Fanning friction factor, f0.0058283140.00639527070.00639527070.0063952707Number of velocity heads99.4280.0000.0000.000Piping DimensionsLookup Table Reference86662222LOOK UP TABLE FOR PIPE DIMENSIONSPipe Nominal Diameter (Inches)0.50.7511.523456810121416182022Schedule5S0.710.921.1851.772.2453.3344.3345.3456.4078.40710.48212.43813.68815.6717.6719.62421.62410S0.6740.8841.0971.6822.1573.264.265.2956.3578.32910.4212.3913.62415.62417.62419.56421.56420ERRORERRORERRORERRORERRORERRORERRORERRORERROR8.12510.2512.2513.37615.37617.37619.2521.2530ERRORERRORERRORERRORERRORERRORERRORERRORERROR8.07110.13612.0913.2515.2517.1241921400.6220.8241.0491.612.0673.0684.0265.0476.0657.98110.0211.93813.1241516.87618.81260ERRORERRORERRORERRORERRORERRORERRORERRORERROR7.8139.7611.62612.81214.68816.518.37620.25800.5460.7420.9571.51.9392.93.8264.8135.7617.6259.56211.37412.514.31216.12417.93819.75100ERRORERRORERRORERRORERRORERRORERRORERRORERROR7.4379.31211.06212.12413.93815.68817.43819.25120ERRORERRORERRORERRORERRORERROR3.6244.5635.5017.1879.06210.7511.81213.56215.251718.75140ERRORERRORERRORERRORERRORERRORERRORERRORERROR7.0018.7510.511.513.12414.87616.518.251600.4660.6120.8151.3381.6872.6243.4384.3135.1876.8138.510.12611.18812.81214.43816.06217.75XS0.5460.7420.9571.51.9392.93.8264.8135.7617.6259.7611.751315171921XXS0.2520.4340.5991.11.5032.33.1524.0634.8976.8758.7510.75ERRORERRORERRORERRORERRORPIPE DIAMETERS0.50.7511.523456810121416182022PIPE TYPES LISTTubing/Glass0.002mmSteel (New)0.050mmSteel (Corroded)1.000mmCast Iron0.260mmConcrete0.300mmRiveted Steel5.000mm

www.myChemE.com

How to Use This Calculationwww.myChemE.comStandard Line Sizing Spreadsheet For GasesRevision 1HOW TO USE THIS CALCULATION1.0IntroductionThis spreadsheet can be used to calculate pressure drops in pipelines, taking account of inline fittings (such asbends, valves and other equipment items.The spreadsheet has four columns which link from one to the next. This can be used to break a piping systemdown into a number of component sections, if needed.2.0How to use this spreadsheet2.1Colour CodingThe following colour coding is used:Boxes shaded light green require a user input.Boxes shaded light blue give a calculated output.2.2Calculation DescriptionThe spreadsheet leaves space to add a Calculation Title at the top, and a Notes Section at the bottomof the sheet. At the top of the calculation column are two boxes ('To' and 'From') to indicate the piperoute.Although these items are not strictly necessary, they help describe the calculation - this can beinvaluable it is to be checked by another engineer. The 'To' and 'From' Sections are particularly usefulif the calculation is split over several columns.2.3Pressure & Temperature DataThe user enters the upstream pressure and the gas temperature in the first column. The spreadsheet thencalculates the downstream pressure - based on the flow, physical property and pipeline data entered (seebelow). The downstream pressure from the first column is transferred across to the upstream pressure ofthe second column, thus allowing a pipework network to be built up.The gas temperature is copied across to the other columns (although this can be overwritten, if required).2.4Gas PropertiesThe user inputs the following gas properties2.4.1Molecular WeightThe user inputs the gas molecular weight in kg/kmol.2.4.2Gas CompressibilityThe user inputs the gas compressibility, z. The gas compressibility is a function of thefrom ideal gas behaviour. Ideal gas behaviour can be assumed for gases at low pressures- i.e. compressibility is 1.0.2.4.3ViscosityThe user inputs the gas viscosity in Centipoise (Cp). It should be noted that viscositychanges with temperature - thus the user must ensure that the viscosity value enteredmust be at the correct temperature.2.5Pipe Data2.5.1Nominal Pipe DiameterThe spreadsheet allows the user to choose from a range of nominal pipe diameters. Availablenominal pipe sizes are: ", ", 1", 1", 2", 3", 4", 5", 6", 8", 10", 12", 14", 16", 18", 20"and 22".2.5.2Pipe ScheduleThe spreadsheet allows the user to choose from a range of available pipe schedules(thicknesses) - these are: 5S, 10S, 20, 30, 40, 60, 80, 100, 120, 140, 160, XS and XXS.By entering the nominal diameter and schedule, the spreadsheet automatically retrieves thecorrect internal diameter of the pipe. It should be noted that not all combinations of nominaldiameter and schedule are permissible; if the wrong combination is selected the spreadsheetdisplays an error. A list of standard pipe sizes can be found by clicking on the link below:List of Standard PipesizesOn occasions, the user may wish to calculate a pressure drop for a non-standard pipe. In thiscase, the user can simply over write the internal diameter cell on the spreadsheet (either ininches or mm).2.5.3Pipe ScheduleThe pressure drop per unit length is affected by the pipe surface roughness - which dependson the materials of construction. The spreadsheet is provided with a range of possible pipematerial types: glass/tubing, steel (new), steel (corroded), concrete and riveted steel. Byselecting the piping material type, the spreadsheet automatically sets the surface roughness.2.6FlowratesThe user enters the required gas mass flowrate in kg per hour. The spreadsheet then calculates thevolumetric 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 pipediameter is reasonable for the required flowrate.2.7Line LossesThe spreadsheet can now be used to determine the line losses (pressure drop) through the system. Theuser enters the total pipe length, as well as the number of inline fittings (bends, valves and Tee-junctions).The spreadsheet then calculates the line losses - see Summary Section below.2.8Other Pressure DropsAs well as line losses, the spreadsheet allows the user to enter other pressure drops not accounted for in.the line losses. These could be:-Pressure drops due to orifice plates.-Pressure drops due to inline instrumentation.-Pressure drops due to control valves-Pressure drops due to equipment itemsChanges in pressure as a result of changes in elevation are invariably negligible for gas systems and areignored.2.9SummaryThe summary section provides a summary of the total pressure drop and the calculated downstreampressure.Unlike liquids, gases are compressible. Therefore, gas density changes with pressure. If the pressuredrop calculated is too great, the density and line velocity will change appreciably. This will result in errorsin the calculation. It is worth noting that as this method uses the density at the upstream conditions, thespreadsheet will under-estimate the actual pressure drop.To obtain reasonable accuracy ensure that the total pressure drop in each column is no more that 10% ofthe upstream pressure. If the pressure drop is greater than 10%, split the calculation over more than onecolumn (See Section 3, "Building a Piping Network" below).3.0Building a Piping NetworkFor pressure drop calculations down a single pipe, only the first column of the pressure drop calculation needs tobe used. The other three calculation columns can be ignored.However, for more complex piping systems, the other calculation columns can be used to build up a piping networkThis 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 secondcolumn and so on. The physical property and flowrate data entered in the first column is copied across to theother three columns to make it easier to set up a network - these values can be overwritten, if required.

&LDisclaimer: 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.www.myChemE.com

TheoryRevision: 1www.myChemE.comStandard Line Sizing Spreadsheet For GasesCALCULATION THEORY1.0IntroductionThis spreadsheet can be used to calculate pressure drops in pipelines, taking account of inline fittings (such asbends, valves and other equipment items. To use the spreadsheet, follow the instructions given in the "How toUse this Spreadsheet" Worksheet.This worksheet presents the equations and algorithms used in the calculation and discusses elements of fluid flowtheory.2.0Calculation of Pressure Drop2.1Determining Pipe DimensionsCommercial pipes come in standard sizes, specified in terms of the nominal pipe diameter, and the pipeschedule. The spreadsheet has this information already stored within the calculation worksheet, linkedto the internal diameter (in inches). The spreadsheet retrieves the correct internal diameter using a Lookupcommand.The internal diameter, d, (in metres) is used to calculate the cross-sectional flow area, A, (in square metres)using Equation 1:2.3Determining Gas DensityUnlike most liquids, gases are compressible fluids - i.e. their density varies with pressure. The spreadsheetcalculates the gas density, r, (in kg/m3) with a modified version of the Ideal Gas Equation. An explanationof the Ideal Gas Equation is given here:Ideal Gas EquationWhere:P -Gas Pressure (in bar(g))MW -Molecular Weight (in kg/kmol)z -Compressibility (Dimensionless)T -Gas temperature (in oC)2.3Determining the Line VelocityThe line velocity, u, (in m/s) is calculated using Equation 3:Where:m -Mass flowrate (in kg/s)A -Cross-sectional flow area (in m2)2.4Calculation of the Reynolds NumberThe Reynolds number is a dimensionless group giving a measure of whether to flow is laminar or turbulent.It is used to estimate the friction factor (see below). A discussion on Reynolds Number and its importancecan be found via the following link:Reynolds NumberThe Reynolds number, Re, is calculated using Equation 4:Wherem -Viscosity (in Pa.s)2.4Calculation of the Pipe Relative RoughnessThe pressure drop from flow down a pipe - at least in turbulent flow - is affected by the roughness of thepipe surface. Obviously, the pipe roughness is determined by the pipe materials of construction. Thespreadsheet provides typical pipe roughness values for a range of materials i.e.MaterialsPipe RoughnessTubing/Glass2.0E-06mSteel (New)5.0E-05mSteel (Corroded)1.0E-03mCast Iron2.6E-04mConcrete3.0E-04mRiveted Steel5.0E-03mTable 1: Roughness values for different pipe materialsThe effect of pipe roughness becomes less important as the pipe diameter increases, thus the spreadsheetcalculates the pipe roughness relative to the pipe diameter using Equation 5.Where:e -Pipe roughness (in m)d -Pipe internal diameter (in m)2.5Calculation of the Fanning Friction FactorThe Fanning Friction Factor is a dimensionless number which, along with the pipe velocity, can be used toestimate the pressure drop of flow down a pipe. It is a function of the Reynolds number and, for turbulentflow, the pipe relative roughness. A introduction to the Fanning Friction Factor can be found via thefollowing link:Fanning Friction FactorThe Fanning Friction Factor can be determined from Charts (Moody Diagram) or by using an empiricalequation. A number of Friction Factor Correlations are available in the literature, the one used in thisspreadsheet is the Churchill Correlation see Equations 6, 7 and 8.WhereandThe Churchill Correlation is used as it is applicable to both laminar and turbulent flow - this is not the caseall correlations.It should be noted that the Fanning Friction Factor is NOT the same as other Friction Factors: i.e. Darcy andMoody2.6Calculation of the Pressure Drop per Unit Length of Straight PipeThe pressure loss as a liquid flows down a straight length of pipe is given by the Darcy Equation. Thisis expressed in Equation 9 below.WhereDPPipe -Pipe line pressure drop (in Pa)LPipe -Pipe length (in m)An introduction to the Darcy Equation is given via the attached link:Introduction to the Darcy EquationIt should be noted that the form of the equation presented via this link uses the Darcy Friction Factor, whichis four times larger than the Fanning Friction Factor. Equation 8 can be adapted to calculate the Pressureper 100 metres by setting LPipe to 100 and converting from Pa to Bar - see Equation 10.2.7Calculation of the Pressure Drop Through Pipe FittingsThe Pressure Drop through pipe fittings (e.g. Pipe bends, Valves, T-Pieces) can be expressed in terms ofa Resistance Coefficient, K, where:N.B. It can be seen from Equations 9 and 11 that the Resistance Coefficient equates to (4fFanningL)/d fora straight length of pipe. The spreadsheet uses the following Resistance Coefficients for different pipefittingsFittingResistance Coeff, K90o Bends0.8Valve1.2Check Valve1.5Straight Tee piece0.1Thru' Tee Piece0.7Table 2: Resistance Coefficient for different pipe fittingsObviously, these values are approximate as K is affected by factors such as radius of the bend and thevalve design. A detailed list of Resistance Coefficients for different pipe fittings is given in Cranes' Flowof Fluids book - see link below.Flow of Fluids Technical GuideThe Line Losses value given in the spreadsheet is the sum of the DPPipe and DPFittings.

&LDisclaimer: 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.KPipeDP=4 fFanning LPipe dr.u22u =mr AEquation (2)fFanning = 2 x128Re1(A + B)1.5+1/12B =37530Re16A = 2.457 x ln0.97Re116+ 0.27 xedEquation (5)Equation (7)Equation (7)No of Velocity HeadsEquation (8)r x 9.81 x Dh

105Equation (11)A =p d4Equation (1)2Re =r u d mEquation (4)Pipe Relative Roughness =edEquation (5)Bar per 100m=4 fFanning x 100 d x 105r.u22Equation (10)metresPa / barFittingsDP=r.u22Equation (10)ElevationDP=Pa / barEquation (3)Equation (6)Equation (8)Equation (9)Equation (11)Equation (11)r =(P + 1.01325) x 105 x MWEquation (2)Equation (2)z x 8314 x (T + 273)www.myChemE.com