SYSTEM DESIGN PROCESS PLANT PIPING OVERVIEW OF
OVERVIEW OFPROCESS PLANT PIPINGSYSTEM DESIGNBy: Vincent A. CarucciCarmagen Engineering, Inc.1
Piping SystemPiping system: conveys fluid betweenlocationsPiping system includes: Pipe Fittings (e.g. elbows, reducers, branchconnections, etc.) Flanges, gaskets, bolting Valves Pipe supports2
ASME B31.3 Provides requirements for:– Design– Materials– Fabrication– Erection– Inspection– Testing For process plants including––––3Petroleum refineriesChemical plantsPharmaceutical plantsTextile plants– Paper plants– Semiconductorplants– Cryogenic plants
Scope of ASME B31.3 Piping and piping components, all fluidservices:– Raw, intermediate, and finished chemicals– Petroleum products– Gas, steam, air, and water– Fluidized solids– Refrigerants– Cryogenic fluids Interconnections within packaged equipment Scope exclusions specified4
Strength 5Yield and Tensile StrengthCreep StrengthFatigue StrengthAlloy ContentMaterial Grain sizeSteel Production Process
Stress - Strain DiagramBSACE6
Corrosion Resistance Deterioration of metal by chemical orelectrochemical action Most important factor to consider Corrosion allowanceadded thickness Alloying increases corrosion resistance7
Piping System CorrosionGeneral orUniformCorrosionUniform metal loss. May be combined with erosion ifhigh-velocity fluids, or moving fluids containingabrasives.PittingCorrosionLocalized metal loss randomly located on materialsurface. Occurs most often in stagnant areas or areas oflow-flow velocity.GalvanicCorrosionOccurs when two dissimilar metals contact each other incorrosive electrolytic environment. Anodic metal developsdeep pits or grooves as current flows from it to cathodicmetal.Crevice Corrosion Localized corrosion similar to pitting. Occurs at placessuch as gaskets, lap joints, and bolts where creviceexists.8ConcentrationCell CorrosionOccurs when different concentration of either a corrosivefluid or dissolved oxygen contacts areas of same metal.Usually associated with stagnant fluid.GraphiticCorrosionOccurs in cast iron exposed to salt water or weak acids.Reduces iron in cast iron, and leaves graphite in place.Result is extremely soft material with no metal loss.
Material Toughness Energy necessary to initiate andpropagate a crack Decreases as temperature decreases Factors affecting fracture toughnessinclude:– Chemical composition or alloying elements– Heat treatment– Grain size9
Fabricability Ease of construction Material must be weldable Common shapes and forms include:– Seamless pipe– Plate welded pipe– Wrought or forged elbows, tees, reducers,crosses– Forged flanges, couplings, valves– Cast valves10
Availability and Cost Consider economics Compare acceptable options based on:– Availability– Relative cost11
Pipe Fittings Produce change in geometry––––12Modify flow directionBring pipes togetherAlter pipe diameterTerminate pipe
Elbow and Return90 45 180 Return13Figure 4.1
TeeReducing Outlet TeeCross TeeFigure 4.214
ReducerConcentricEccentricFigure 4.315
Welding Outlet Fitting16Figure 4.4
CapFigure 4.517
Lap-joint Stub EndNote square cornerRREnlarged Sectionof Lap18Figure 4.6
Typical Flange AssemblyFlangeBoltingGasket19Figure 4.7
Types of FlangeAttachment and FacingFlange Attachment TypesFlange Facing TypesThreaded FlangesFlat FacedSocket-Welded FlangesBlind FlangesRaised FaceSlip-On FlangesLapped FlangesRing JointWeld Neck Flanges20Table 4.1
Flange Facing Types21Figure 4.8
Gaskets Resilient materialInserted between flangesCompressed by bolts to create sealCommonly used types– Sheet– Spiral wound– Solid metal ring22
Flange Rating Class Based on ASME B16.5 Acceptable pressure/temperaturecombinations Seven classes (150, 300, 400, 600, 900,1,500, 2,500) Flange strength increases with classnumber Material and design temperaturecombinations without pressure indicatednot acceptable23
Material Specification List24Table 4.2
Pressure - Temperature RatingsMaterialGroup No.ClassesTemp., F-20 to 10485450320215Table 70940885805785755710675650600505345
Sample Problem 1Flange RatingNew piping system to be installed atexisting plant.Determine required flange class. Pipe Material: Design Temperature: Design Pressure:261 1 Cr 1 Mo42700 F500 psig
Sample Problem 1 Solution Determine Material Group Number (Fig. 4.2)Group Number 1.9 Find allowable design pressure atintersection of design temperature and GroupNo. Check Class 150.– Allowable pressure 110 psig design pressure– Move to next higher class and repeat steps For Class 300, allowable pressure 570 psig Required flange Class: 30027
Valves Functions– Block flow– Throttle flow– Prevent flow reversal28
Full Port Gate 19.20.21.22.29Handwheel NutHandwheelStem NutYokeYoke BoltingStemGland FlangeGlandGland Bolts orGland Eye-bolts and nutsGland Lug Bolts and NutsStem PackingPlugLantern RingBackseat BushingBonnetBonnet GasketBonnet Bolts and NutsGateSeat RingBodyOne-Piece Gland (Alternate)Valve PortFigure 5.1
Globe Valve 30Most economic for throttling flowCan be hand-controlledProvides “tight” shutoffNot suitable for scraping or roddingToo costly for on/off block operations
Check Valve Prevents flow reversalDoes not completely shut off reverse flowAvailable in all sizes, ratings, materialsValve type selection determined by– Size limitations– Cost– Availability– Service31
Swing Check ure 5.2
Ball Check Valve33Figure 5.3
Lift Check ValveSeatRingPistonFlowDirection34Figure 5.4
Wafer Check Valve35Figure 5.5
Ball ValveNo.1234567891011121314151617181936Part NamesBodyBody CapBallBody Seal GasketSeatStemGland FlangeStem PackingGland FollowerThrust BearingThrust WasherIndicator StopSnap RingGland BoltStem BearingBody Stud Bolt & NutsGland CoverGland Cover BoltsHandleFigure 5.6
Plug ValveWedgeMolded-In Resilient SealSealing Slip37Figure 5.7
Valve Selection ProcessGeneral procedure for valve selection.1. Identify design information includingpressure and temperature, valve function,material, etc.2. Identify potentially appropriate valvetypes and components based onapplication and function(i.e., block, throttle, or reverse flowprevention).38
Valve Selection Process,cont’d3. Determine valve application requirements(i.e., design or service limitations).4. Finalize valve selection. Check factors toconsider if two or more valves aresuitable.5. Provide full technical descriptionspecifying type, material, flange rating,etc.39
Exercise 1 - DetermineRequired Flange Rating Pipe:1 1 Cr 1 Mo42 Flanges: Design Temperature: Design Pressure:A-182 Gr. F11900 F375 psig40
Exercise 1 - Solution1. Identify material specification of flangeA-182 Gr, F112. Determine Material Group No. (Table 4.2)Group 1.93. Determine class using Table 4.3 with designtemperature and Material Group No.– The lowest Class for design pressure of 375psig is Class 300.– Class 300 has 450 psig maximum pressureat 900 F41
Design Conditions General– Normal operating conditions– Design conditions Design pressure and temperature– Identify connected equipment and associateddesign conditions– Consider contingent conditions– Consider flow direction– Verify conditions with process engineer42
Loading ConditionsPrincipal pipe load types Sustained loads– Act on system all or most of time– Consist of pressure and total weight load Thermal expansion loads– Caused by thermal displacements– Result from restrained movement Occasional loads43– Act for short portion of operating time– Seismic and/or dynamic loading
Stresses Produced ByInternal PressureSlScPt44Sl Longitudinal StressSc Circumferential (Hoop) Stresst Wall ThicknessP Internal PressureFigure 6.1
Stress Categorization Primary Stresses– Direct– Shear– Bending Secondary stresses– Act across pipe wall thickness– Cause local yielding and minor distortions– Not a source of direct failure45
Stress Categorization, cont’d Peak stresses– More localized– Rapidly decrease within short distance oforigin– Occur where stress concentrations andfatigue failure might occur– Significance equivalent to secondary stresses– Do not cause significant distortion46
Allowable StressesFunction of– Material properties– Temperature– Safety factorsEstablished to avoid:– General collapse or excessive distortion fromsustained loads– Localized fatigue failure from thermalexpansion loads– Collapse or distortion from occasional loads47
B31.3 AllowableStresses in TensionBasic Allowable Stress S, ksi. At Metal Temperature, F.MaterialSpec. No/Grade10020030040050060070080090012001300 14001500Carbon SteelA 106B20.020.020.020.018.917.316.510.86.52.51.0C - ½MoA 335P118.318.317.516.916.315.715.113.512.74.2.41¼ - ½MoA 218Cr - 8Ni pipeA 312TP304 .31.416Cr - 12Ni-2MopipeA 312TP316 2.31.3Table 6.1481000 1100
Pipe Thickness RequiredFor Internal Pressure PDt 2 (SE PY )P Design pressure, psigD Pipe outside diameter, in.S Allowable stress in tension, psiE Longitudinal-joint quality factorY Wall thickness correction factor 49t m t CAt nom tm0.875
Spec.No.Class (or Type)DescriptionEjCarbon SteelAPI5L.Seamless pipeElectric resistance welded pipeElectric fusion welded pipe, double butt, straight orspiral seamFurnace butt welded1.000.850.95A 53Type SType EType FSeamless pipeElectric resistance welded pipeFurnace butt welded pipe1.000.850.60A 106.Seamless pipe1.00Low and Intermediate Alloy SteelA 333.Seamless pipeElectric resistance welded pipe1.000.85A 335.Seamless pipe1.00Stainless SteelA 312.Seamless pipeElectric fusion welded pipe, double butt seamElectric fusion welded pipe, single butt seam1.000.850.80A 3581, 3, 452Electric fusion welded pipe, 100% radiographedElectric fusion welded pipe, spot radiographedElectric fusion welded pipe, double butt seam1.000.900.85Nickel and Nickel Alloy50B 161.Seamless pipe and tube1.00B 514.Welded pipe0.80B 675AllWelded pipe0.80Table 6.2
Temperature, FMaterials900 & lower9501000105011001150 & 40.4Cast iron0.0.Table 6.351
Curved and Mitered Pipe Curved pipe– Elbows or bends– Same thickness as straight pipe Mitered bend– Straight pipe sections welded together– Often used in large diameter pipe– May require larger thickness Function of number of welds, conditions, size52
Sample Problem 2 Determine Pipe Wall ThicknessDesign temperature: 650 FDesign pressure: 1,380 psig.Pipe outside diameter: 14 in.Material: ASTM A335, Gr. P11 ( 1 14 Cr 12 Mo ),seamlessCorrosion allowance: 0.0625 in.53
Sample Problem 2 - SolutionPDt 2(SE PY )1,380 14t 2[(16,200 1) (1,380 0.4 )]t 0.577 in.54
Sample Problem 2 Solution, cont’dtm t c 0.577 0.0625 0.6395 in.0.6395t nom 0.731 in.0.87555
Welded Branch ConnectionDbTbReinforcementZone .cthMillTol.d1A2A2d2d2βPipe C56ReinforcementZone LimitsFigure 6.2
Reinforcement AreaDb 2(Tb c)d1 sin βd1 Effective length removed from run pipe, in.Db Branch outside diameter, in.Tb Minimum branch thickness, in.c Corrosion allowance, in.β Acute angle between branch and header57
Required Reinforcement AreaRequired reinforcement area, A1:A 1 t h d1(2 sin β)Where: th Minimum required headerthickness, in.58
Reinforcement Pad Provides additional reinforcement Usually more economical than increasingwall thickness Selection variables– Material– Outside diameter– Wall thicknessæ (Dp Db ) öTrA 4 ççè sin β59
Sample Problem 3 Pipe material: Seamless, A 106/Gr. B forbranch and header, S 16,500 psi Design conditions: 550 psig @ 700 F c 0.0625 in. Mill tolerance: 12.5%60
Sample Problem 3, cont’d Nominal PipeThicknesses:Header: 0.562 in.Branch: 0.375 in. Required PipeThicknesses:Header: 0.395 in.Branch: 0.263 in. Branch connection at 90 angle61
Sample Problem 3 - SolutionDb 2(Tb c)d1 sin β16 2 (0.375 0.875 0.0625 )d1 15.469 in.sin 90 A1 thd1(2 sinβ)A1 0.395 15.469 (2 sin90 ) 6.11 in.262
Sample Problem 3 Solution, cont’d Calculate excess area available in header, A2.A 2 (2d2 d1)(Th th c )d2 d1 15.469 in. Dh 24 in.A2 (2 15.469 - 15.469) (0.875 0.562 0.395 - 0.0625)A2 0.53 in.263
Sample Problem 3 Solution, cont’d Calculate excess area available in branch, A3.2L 4 (Tb tb c )A3 sinβL 4 2.5 (0.875 0.375 0.0625 ) 0.664 in.A3 642 0.664 (0.875 0.375 0.263 0.0625 ) 0.003 in.2sin 90
Sample Problem 3 Solution, cont’d Calculate other excess area available, A4.A4 0. Total Available Area:AT A2 A3 A4AT 0.53 0.003 0 0.533 in.2 availablereinforcement.AT A1 Pad needed65
Sample Problem 3 Solution, cont’d Reinforcement pad: A106, Gr. B, 0.562 in. thick Recalculate Available ReinforcementL41 2.5 (Th - c) 2.5 (0.875 0.562 - 0.0625) 1.073 in.L42 2.5 (Tb - c) Tr 2.5 (0.875 0.375 - 0.0625) 0.562 (0.875) 1.16 in66
Sample Problem 3 Solution, cont’dTherefore, L4 1.073 in.2L 4 (Tb t b c)A3 sin βA3 2 1.073 (0.875 0.375 0.263 0.0625 )sin90 oA 3 0.005 in.2 (vs. the 0.003 in.2 previously calculated )A T A 2 A 3 A 4 0.53 0.005 0 0.535 in.267
Sample Problem 3 Solution, cont’d Calculate additional reinforcement required andpad dimensions:A4 6.11 - 0.535 5.575 in.2Pad diameter, Dp is:Tr 0.562 (0.875) 0.492 in.A 4 Db5.575Dp 16 27.3Tr sin β 0.492Since 2d2 Dp, pad diameter is acceptable68
Exercise 2 - DetermineRequired Pipe Wall Thickness 69Design Temperature: 260 FDesign Pressure: 150 psigPipe OD: 30 in.Pipe material: A 106, Gr. B seamlessCorrosion allowance: 0.125Mill tolerance: 12.5%Thickness for internal pressure andnominal thickness?
Exercise 2 - Solution From Tables 6.1, 6.2, and 6.3 obtain values:– S 20,000 psi– E 1.0– Y 0.4 Thickness calculation:PD150 30t 2(SE PY ) 2[(20,000 1.0 ) (150 0.04 )]t 0.112 in.70
Exercise 2 - Solution, cont’d Corrosion allowance calculation:t m t CA 0.112 0.125t 0.237 in. Mill tolerance calculation:t nomt nom71tm0.237 0.875 0.875 0.271 in.
Layout Considerations Operational– Operating and control points easily reached Maintenance– Ample clearance for maintenance equipment– Room for equipment removal– Sufficient space for access to supports Safety– Consider personnel safety– Access to fire fighting equipment72
Pipe Supports and Restraints Supports– Absorb system weight– Reduce: longitudinal pipe stress pipe sag end point reaction loads Restraints73– Control or direct thermal movement due to: thermal expansion imposed loads
Support and RestraintSelection Factors 74Weight loadAvailable attachment clearanceAvailability of structural steelDirection of loads and/or movementDesign temperatureVertical thermal movement at supports
Rigid SupportsShoeDummy Support75Base AdjustableSupportSaddleFigure 7.1Trunnion
Hangers76Figure 7.2
Flexible SupportsLoad and DeflectionScaleSmall Change inEffective Lever ArmLarge Change inEffective Lever ArmRelativelyConstantLoadTypical Constant-LoadSpring Support MechanismTypical Variable-LoadSpring Support77Figure 7.3
Restraints Control, limit, redirect thermal movement– Reduce thermal stress– Reduce loads on equipment connections Absorb imposed loads– Wind– Earthquake– Slug flow– Water hammer– Flow induced-vibration78
Restraints, cont’d Restraint Selection– Direction of pipe movement– Location of restraint point– Magnitude of load79
Anchors and Guides Anchor– Full fixation– Permits very limited (if any) translation orrotation Guide– Permits movement along pipe axis– Prevents lateral movement– May permit pipe rotation80
Restraints - AnchorsAnchor81AnchorFigure 7.4Partial Anchor
Restraints - GuidesGuideGuidexVertical Guide82GuideFigure 7.5
Piping Flexibility Inadequate flexibility– Leaky flanges– Fatigue failure– Excessive maintenance– Operations problems– Damaged equipment System must accommodate thermalmovement83
Flexibility Analysis Considers layout, support, restraint Ensures thermal stresses and reactionloads are within allowable limits Anticipates stresses due to:84– Elevated design temperatures Increases pipe thermal stress and reactionloads Reduces material strength– Pipe movement– Supports and restraints
Flexibility Analysis, cont’d Evaluates loads imposed on equipment Determines imposed loads on pipingsystem and associated structures Loads compared to industry standards– Based on tables– Calculated85
Design Factors Layout Componentdesign details Fluid service Connectedequipment type Operatingscenarios86 Pipe diameter,thickness Design temperatureand pressure End-point movements Existing structuralsteel locations Special designconsiderations
Equipment Nozzle LoadStandards and ParametersEquipment Item87Parameters UsedTo DetermineAcceptable LoadsIndustry StandardCentrifugal PumpsAPI 610Nozzle sizeCentrifugalCompressorsAPI 617, 1.85 timesNozzle size, materialAir-Cooled HeatExchangersAPI 661NEMA SM-23allowableNozzle sizePressure Vessels, Shell- ASME Code Sectionand-Tube HeatVIII, WRC 107,Exchanger NozzlesWRC 297Nozzle size, thickness,reinforcement details,vessel/exchanger diameter,and wall thickness. Stressanalysis required.Tank NozzlesAPI 650Nozzle size, tank diameter,height, shell thickness, nozzleelevation.Steam TurbinesNEMA SM-23Nozzle sizeTable 7.1
Computer Analysis Used to perform detailed piping stressanalysis Can perform numerous analyses Accurately completes unique and difficultfunctions88– Time-history analyses– Seismic and wind motion– Support motion– Finite element analysis– Animation effects
Computer Analysis GuidelinesPipe Size, NPSMaximum DifferentialFlexibility Temp. 4 400 F 8 300 F 12 200 F 20anyFor rotating equipment 3AnyFor air-fin heat exchangers 4AnyFor tankage 12AnyType Of PipingGeneral piping89Table 7.2
Piping Flexibility Temperature Analysis based on largest temperaturedifference imposed by normal andabnormal operating conditions Results give:– Largest pipe stress range– Largest reaction loads on connections,supports, and restraints Extent of analysis depends on situation90
Normal TemperatureConditions To ConsiderStableOperationTemperature range expected for most of time plant isin operation. Margin above operating temperature(i.e., use of design temperature rather than operatingtemperature) allows for process flexibility.Startup andShutdownDetermine if heating or cooling cycles pose flexibilityproblems. For example, if tower is heated whileattached piping remains cold, piping flexibility shouldbe checked.Regenerationand DecokingPipingSparedEquipment91Design for normal operation, regeneration, ordecoking, and switching from one service to theother. An example is furnace decoking.Requires multiple analyses to evaluate expectedtemperature variations, for no flow in some of piping,and for switching from one piece of equipment toanother. Common example is piping for two or morepumps with one or more spares.Table 7.3
Abnormal TemperatureConditions To Conside
Fittings (e.g. elbows, reducers, branch connections, etc.) Flanges, gaskets, bolting Valves Pipe supports. 3 ASME B31.3 –Design – Materials – Fabrication – Petroleum refineries – Chemical plants – Pharmaceutical plants – Textile plants – Paper plants – Semiconductor plants – Cryogenic plants
piping classes and the numerous piping specifications necessary to fabricate, test, insulate, and paint the piping systems, is titled either the piping material engineer or the piping spec(ification) writer. 1.2. Job Scope Whatever the title, the piping material engineer (PME) is a very important person within the Piping Design Group and .
dependent on the plant design system being used to create the PCF. Most Piping Fabricators that can receive piping information in the form of PCF's will probably have the Spoolgen software from Hexagon (previously Intergraph). This software is derived from the Isogen piping isometric software that used to be the de-facto piping isometric .
liquid process piping systems, engineering calculations and requirements for all piping systems, basics of metal piping systems and thermoplastic piping systems. In Part 2 - the course will continue from Part 1 and review the basics of Rubber and Elastomer Piping Systems, Thermoset Piping Systems, Double Containment
www.DaikinApplied.com 9 AG 31-011 REFRIGERANT PIPING DESIGN. Piping Design Basics. Good piping design results in a balance between the initial cost, pressure drop, and system reliability. The initial cost is impacted by the diameter and layout of the piping.The pressure drop in the piping must be minimized to avoid
plant operations & maintenance, process engineering, plant piping & pipeline layout, design, analysis & Construction experience. He has served in GSWS Kingdom of Saudi Arabia as Plant Piping Engineer responsible for construction, operations & maintenance of Power Piping for a Power Plant having capacity of 1200 MW.
ASME B31.1, Power Piping ASME B31.3, Process Piping ASME B31.9, Building Services Piping AWWA Standards C200, C206, C900. 3.2.1 Piping Design Criteria Selection of inappropriate codes, standards, and requirements could add to the cost of design and construction. Thus, selection of piping standards such as ASME B31.1, B31
A. ASME B31.1 - Power piping. B. ASME B31.2 - Fuel Gas Piping. C. ASME B31.3 - Process piping. D. ASME B31.4 - Pipeline Transportation system for liquid hydrocarbon & other liquid. E. ASME B31.5 - Refrigeration Piping. F. ASME B31.8 - Gas transmission & distribution piping system. G. ASME B31.9 - Buil
NAVCO Piping Datalog, 11th edition, 2005 Piping Design Handbook edited by J.J. McKetta, Jr and W.A. Cunningham, Marcel Dekker, Inc. 1992 Piping Handbook, 7th edition, Mohinder L Nayyer, McGraw-Hill Handbook, 2006 Process Plant Layout and Piping Design, Ed Bausbacher & Roger Hunt, Prentice Hall, 1993 The Piping Guide: For the Design and Drafting .
