CM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsSlide Number 34CM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120 Piping SystemsCM4120Piping Systems1Piping Systems in the Chemical Process Industries – part 2March, 2009{ Quick Review of part 1{ Design of Process Piping SystemsCM4120Piping Systems2Piping Systems include:{ Pipe, Flanges, Fittings{ Bolting, Gaskets{ Valves{ Hangers and Supports{ Insulations, Coverings, Coatings{ Heat TracingEverything between the equipment and instrumentation is part of the piping systemCM4120Piping Systems3Lowest Cost over Lifetime of Piping System, however:Primary Design Consideration is Safetyy Expected Process Conditions{ Temperature, Pressure{ Chemical compatibility, Corrosion allowances{ Vibration, flexing, bending{ Thermal cyclingy Do any Special Considerations apply{ Operability and Serviceability{ Maintenance or Construction Loading{ Sanitary requirementsy What are the Local Environmental Conditions{ Temperature extremes, Wind, Hurricane, Lightening, etc.{ Earthquake, Permafrost, etc.{ Proximity to civilian activitiesy Evaluate Performance in a Fire SituationCM4120Piping Systems4y ASME Boiler and Pressure Vessel Codey ASME B31: Code for Pressure Pipingy ANSI Standards – dimensions for valves, piping, fittings, nuts/washers, etc.y ASTM Standards for piping and tubey API – Specs for pipe and pipelinesy AWS, ASHRAE, NFPA, PPI, UL, etc.CM4120Piping Systems5What is Pipe Schedule?{ Schedule = P/S * 1000P = max. working pressure of pipe, psigS = allowable stress in piping material, psiFor carbon steel pipe, S = 36,000 psi{ What is max. working pressure for Schedule 40 Carbon Steel pipe?psigP 14401000000,36*40==CM4120Piping Systems6Piping Design Process – a three step approach1. Design for Flow{ Find min. diameter to achieve desired flow velocity2. Design for Pressure Integrity{ Find min. wall thickness for process and external conditions{ Find appropriate rating of in-line components3. Re-check for Flow CriteriaCM4120Piping Systems7Criteria for Step 1: “Design for Flow”y EconomicsServiceable over Design LifeSmallest diameter usually is lowest costUsually start with Schedule 40y PerformanceTypical flow velocity listed in Plant Design textbooksMinimum entrainment velocity for slurriesPrevent erosion or cavitationCM4120Piping Systems8Design Rules of Thumb when sizing for velocity...Water lines: 3-10 ft/secAir lines: 50-100 ft/secPump discharge: 3-12 ft/secPump suction: (1/3 x discharge velocity)Steam: low pressure (25 psig or less) 50-100 ft/sechigh pressure (>100 psig) 100-200 ft/secSlurries: > min. entrainment velocityfrom Peters and Timmerhaus, Plant Design and Economics for Chemical Engineers, 4thed., McGraw-Hill, 1991.CM4120Piping SystemsStep 2: “Design for Pressure Integrity”Determine min. req’d wall thickness:Follow the Pressure Integrity Design Method, ASME B31.X9()APySe2PDtm ++=tm=min. wall thickness, in.P=design pressure, psigD=O.D. of pipe, in.S=allowable stress, psie=weld joint efficiency, unitlessy=factor to adjust for temp, unitlessA= add’l thickness for corrosion or external loads, in.CM4120Piping Systems10Step 3. Re-check velocityAfter calculating tm, wall thickness:If tmis less than twallfor Sched 40{ Stay with Sched 40 for small diameter piping{ Check cost for thinner wall of larger pipeIf tmis greater than twallfor Sched 40{ Try Sched 80 then re-check velocityCM4120Piping Systems11Once pipe size is determined:Select in-line components;Determine insulation thickness/type, coverings, coatings;Design and locate supports and hangers.CM4120Piping Systems12Inline Components:FittingsValvesGaskets, Seals, and Thread SealantsConnection Hardware – Bolts, studs, nuts, washersCM4120Piping Systems13Pipe Fittings - Steel{ Forged{ Cast{ Malleable IronSelect “Class” of Fittings{ 150 lb., 300 lb., 600 lb., etc.{ Need a look-up table to determine max. allowable Pressure at the design TemperatureCM4120Piping Systems14Maximum Allowable non-shock Pressure (psig)Temperature(oF)Pressure Class Rating for Flanged Fittings (lb)150 300 400 600 900 1500 2500Hydrostatic Test Pressure (psig)450 1125 1500 2225 3350 5575 9275-20 to 100 285 740 990 1480 2220 3705 6170200 260 675 900 1350 2025 3375 5625300 230 655 875 1315 1970 3280 5470400 200 635 845 1270 1900 3170 5280500 170 600 800 1200 1795 2995 4990600 140 550 730 1095 1640 2735 4560650 125 535 715 1075 1610 2685 4475700 110 535 710 1065 1600 2665 4440750 95 505 670 1010 1510 2520 4200800 80 410 550 825 1235 2060 3430850 65 270 355 535 805 1340 2230900 50 170 230 345 515 860 1430950 35 105 140 205 310 515 8601000 20 50 70 105 155 260 430Ratings for flanged steel pipe fittings, ANSI B16.5 - 1988.http://www.engineeringtoolbox.com/ansi-flanges-pressure-temperature-d_342.htmlCM4120Piping Systems15Design Checklist:Select pipe for process and environmental conditions;Select in-line components;Determine insulation thickness/type, coverings, coatings;Design and locate supports and hangers.CM4120Piping Systems16Piping InsulationPrevent heat loss/ gainPrevent condensation – below ambientPersonnel protection – over 125oFFreeze protection – outdoor cold climates, may need TracingFire protectionNoise controlCM4120Piping Systems17Recommended minimum Thickness of Insulation (inches)*Nominal Pipe SizeNPS(inches)Temperature Range (oC)50 - 90 90 - 120 120 - 150 150 - 230Temperature Range (oF)120 - 200 201 - 250 251 - 305 306 - 450Hot WaterLow Pressure SteamMedium