Transcription

Engineering & PipingDesign GuideFiberglass Reinforced Piping Systemswww.fgspipe.com

I N T R O D UC T I ONNOV Fiber Glass Systems’ fiberglass reinforced epoxy andvinyl ester resin piping systems possess excellent corrosionresistance and a combination of mechanical and physicalproperties that offer many advantages over traditional pipingsystems. We are recognized worldwide as a leading supplierof piping systems for a wide range of chemical and industrialapplications.This manual is provided as a reference resource for someof the specific properties of our piping systems. It is not intended to be a substitute for sound engineering practices asnormally employed by professional design engineers.NOV Fiber Glass Systems has an international network ofdistributors and trained field personnel to advise on properinstallation techniques. It is recommended they be consultedfor assistance when installing the piping system. This notonly enhances the integrity of the piping system, but also increases the efficiency and economy of the installation.Additional information regarding installation techniques isprovided in the following installation manuals:Manual No. F6000Pipe Installation Handbookfor Tapered Bell & Spigot JointsManual No. F6080Pipe Installation Handbookfor Straight Socket Joints andButt & Wrap JointsManual No. F6300Pipe Installation Handbookfor Marine-Offshore PipingPIPING SYSTEMSEpoxy Resin Systems:· Z-Core (High Performance Resin)· Centricast Plus RB-2530· Centricast RB-1520· Green Thread · Marine-Offshore· Green Thread 175· Green Thread 175 Conductive· Green Thread 250· Green Thread 250 Conductive· Green Thread 250 Fire Resistant· Red Thread II· Red Thread II JP· Silver Streak (FGD Piping)· Ceram Core (Ceramic-lined Piping)· F-Chem (Custom Piping)· HIGH PRESSURE Line Pipe andDownhole Tubing*Vinyl Ester Systems:· Centricast Plus CL-2030· Centricast CL-1520· F-Chem (Custom Piping)* Available from NOV Fiber Glass Systems,San Antonio, TexasPhone: (210) 434-5043 · FAX: (210) 434-7543Web site: http://www.fgspipe.comGeneral Policy StatementNational Oilwell Varco has produced this brochure for general information only,and it is not intended for design purposes. Although every effort has been made tomaintain the accuracy and reliability of its contents, National Oilwell Varco in no wayassumes responsibility for liability for any loss, damage or injury resulting from the useof information and data herein nor is any warranty expressed or implied. Always crossreference the bulletin date with the most current version listed at the web site noted inthis literature.SAFETYThis safety alert symbol indicates an importantsafety message. When you see this symbol, bealert to the possibility of personal injury.iiNOV Fiber Glass Systems has developed a computer program specifically for our fiberglass products. This softwareprogram called Success By Design is available on ourweb site at http://www.fgspipe.com.

TA B LE O F CONTENT SIntroduction. iiPiping System Selection and Applications. 1SECTION 1 — Flow Properties.2Preliminary Pipe Sizing.2Detailed Pipe SizingA. Liquid Flow.2B. Loss in Pipe Fittings.4C. Open Channel Flow.5D. Gas Flow.5SECTION 2 — Above Ground System Design UsingSupports, Anchors & Guides.7Piping Support DesignA. Support Design.7B. Guide Design.8C. Anchor Design.9D. Piping Support Span Design.11SECTION 3 — Temperature Effects. 12System Design.12Thermal Properties and Characteristics.12Fundamental Thermal Analysis FormulasA. Thermal Expansion and Contraction. 13B. Anchor Restraint Load.13C. Guide Spacing.13Flexibility Analysis and DesignA. Directional Change Design.13B. Expansion Loop Design.14C. Expansion Joint Design.14D. Heat Tracing.15E. Thermal Conductivity.16F. Thermal Expansion in Buried Pipe. 16G. Pipe Torque due to Thermal Expansion. 16SECTION 4 — Pipe Burial.17Pipe Flexibility.17Burial AnalysisA. Soil Types.17B. Soil Modulus .18Trench Excavation and PreparationA. Trench Size.18B. Trench Construction.18C. Maximum Burial Depth.19D. Roadway Crossing.19Bedding and BackfillA. Trench Bottom.20B. Backfill Materials.20C. Backfill Cover.20D. High Water Table.20SECTION 5 — Other Considerations. 21A. Abrasive Fluids. 21B. Low Temperature Applications. 21C. Pipe Passing Through Walls orConcrete Structures. 21D. Pipe Bending. 21E. Static Electricity. 22F. Steam Cleaning. 22G. Thrust Blocks. 22H. Vacuum Service. 22I. Valves .22J. Vibration. 23K. Fluid (Water) Hammer.23L. Ultraviolet (U.V.) Radiation and Weathering. 23M. Fungal, Bacterial, and Rodent Resistance. 23SECTION 6 — Specificationsand Approvals. 24A. Compliance with National Specifications. 24B. Approvals, Listings, and Compliancewith Regulations. 24AP PENDICESAppendix A Useful Formulas.27Appendix B Conversions.30LI S T OF TABLESTable 1.0 Typical Applications.1Table 1.1 Flow Resistance K Values for Fittings. 4Table 1.2 Typical Liquid Properties.4Table 1.3 Typical Gas Properties.6Table 2.0 Minimum Support Width. 7Table 2.1 Saddle Length.8Table 4.0 Recommended Bedding and Backfill. 18Table 4.1 Nominal Trench Widths.18Table 6.0 ASTM D2310 Classification. 24Table 6.1 Classifying Fiberglass Flangesto ASTM D4024.25Table 6.2 Classifying Fiberglass PipeUsing ASTM D2310 andSpecifying Pipe Using ASTM D2996and D2997.26iii

P I P IN G S Y STEM S ELECTION AN D A PP LICATION SPIPING SYSTEM SELECTIONTYPICAL APPLICATIONSWhen selecting a piping system for a particular application,it is important to consider the corrosive characteristics ofthe media to which the pipe and fittings will be exposed, thenormal and potential upset temperatures and pressures ofthe system, as well as other environmental factors associated with the project. Fiberglass reinforced plastic (FRP)piping systems provide excellent corrosion resistance, combined with high temperature and pressure capabilities, allat a relatively low installed cost. NOV Fiber Glass Systemsengineers, using epoxy, vinyl ester, and polyester resins,have developed a comprehensive array of piping systemsdesigned to meet the most demanding application requirements. Piping systems are available with liners of varyingtype and thickness, with molded, fabricated, or filamentwound fittings, ranging in size from 1" to 72"(25 to 1800 mm)in diameter.Fiberglass piping is used in most industries requiring corrosion resistant pipe. FRP piping is used in vent and liquid applications that operate from -70 F to 300 F (-57 C to149 C). NOV Fiber Glass Systems piping systems use highgrade resins that are resistant to acids, caustics or solvents.Abrasion resistant materials can be used in the piping innersurface liner to enhance wear resistance to slurries. Table1.0 is a brief list of the many applications and industrieswhere fiberglass piping has been used successfully. SeeBulletin No. E5615 for a complete chemical resistance guide.Our piping systems can be installed in accordance with theASME B 31.3 piping code. Second party listings from regulatory authorities such as Factory Mutual, NSF, UL/ULC,and marine registrars are in place on several of these pipingsystems.TABLE 1.0 Typical Fiberglass Pipe Applications by IndustryINDUSTRYApplications ChemicalPetro MarineProcess Chemical p and Waste Water Mining andPaper TreatmentMetal RefiningAeration XBrine SlurryXBottom AshXChemical FeedXXXXXXColumn PipingXCondensate ReturnXXXXXXXXConduitXXXXCooling WaterXXXXDisposal WellsXXXXDownholeTubing& CasingXXXEffluent DrainsXXXXXXXXFire MainsXXXXXXXXFlue GasDesulfurization XGuttering &DownspoutsXXOily WaterXScrubber HeadersXXSeawater XXXXXXSlurryXVentsXXXXXXXWaterXXXXXXXXWaste TreatmentXXXXXXXXXBuried Gasoline X1XXX

SECTION 1. Flow PropertiesThe smooth interior surface of fiberglass pipe, combined withinside diameters larger than steel or thermoplastic pipe of thesame nominal diameter, yield significant flow advantages.This section provides design techniques for exploiting theflow capacity of fiberglass pipe.A. Liquid FlowFluid flow characteristics are very sensitive tothe absolute roughness of the pipe inner surface.The absolute roughness of NOV FiberGlass Systems piping is (0.00021 inches) 1.7 x10 -5 feet (1). This is less than 1/8 the average value for(non-corroded) new steel of (0.0018 inch) 15 x 10-5 feet(2).For ambient temperature water, the equivalent Manningvalue (n) is 0.009 and the Hazen-Williams coefficient is150.Preliminary Pipe SizingThe determination of the pipe size required to transport a givenamount of fluid is the first step in designing a piping system.Minimum recommended pipe diameters.The most commonly used pipe head loss formula is theDarcy-Weisbach equation.Clear fluidsEq. 1Eq. 5Where:Corrosive or erosive fluidsHf Pipe friction loss, ft(m)f Friction factorL Length of pipe run, ft (m)Eq. 2D Inner diameter, ft (m)V Fluid velocity, ft/sec (m/sec)g Acceleration of gravity, 32.2 ft/s2 (9.81 m/s2)Where:d Pipe inner diameter, inchThe friction factor is dependent on the flow conditions, pipediameter and pipe smoothness. The flow conditions aredetermined by the value of the Reynolds Number. Thereare four flow zones defined by the Reynolds Number; theyare laminar, critical, transitional and turbulent.Q Flow rate, gal/min (gpm)Sg Fluid specific gravity, dimensionlessp Fluid density, lb/ft3For laminar flow (Reynolds Number below 2,000), thefriction factor is calculated by Eq. 6Recommended maximum fluid velocitiesClear fluidsEq. 6Eq. 3Where Nr is the dimensionless Reynolds NumberCorrosive or erosive fluidsEq. 7Eq. 4Where:D Pipe inner diameter, ft (m)Where:V Fluid velocity, ft/sec (m/sec)V velocity, ft/secp fluid density,v lb/ft3Fluid kinematic viscosity, ft2/sec (m2/sec)Nr Reynolds Numberf Friction FactorTypical fiberglass piping systems are operated at flow velocities between 3 & 12 ft/sec.Detailed Pipe Sizing1Based on testing at Oklahoma State University in Stillwater, OK.2 CameronHydraulic Data, Ingersoll-Rand, Seventeenth Edition, 1988.2

For turbulent flow (Reynolds Number greater than4,000), the friction factor is calculated by the ColebrookEquation.Eq. 84,000 is considered the critical zone. Flow is neither fullylaminar or turbulent, although it is often assumed to belaminar for calculation purposes. Flow with Reynoldsnumbers between 4,000 and 10,000 is called the transitional zone where use of the Colebrook equation is considered more appropriate.These equations are quickly solved using a computerprogram, Success By Design, developed by NOV FiberGlass Systems specifically for our fiberglass products.Where:D Pipe inner diameter, inch (mm)e Absolute roughness, inch (mm)A demonstration of the Darcy-Weisbach and Colebrookequations for fiberglass pipe is shown in Figure 1.0.Nr Reynolds Number, unit lessf Friction Factor, unit lessThe flow with Reynolds numbers between 2,000 andFiberglass Pipe Pressure Loss Curves for WaterFigure 1.0Basis: Specific Gravity of 1.0 and Viscosity of 1.0 cps252010454"60"72"3210.00113108"0.0110"12"16 14""20 18" "24"30"36"42"48"PipeI3"nnerDia(inme 4"chter)6"1.5"0.12"1"Pressure Loss - psig per 100 Feet of Pipe15Ve10loc(Ftit/Se yc) 751001,00010,000Flow Rate (gpm) - Gallons per Minute100,000

B. Loss in Pipe FittingsTypical values of k are given in Table 1.1.The head loss through a fitting is proportional to thefluid velocity squared (V2). Equation 9 relates the headloss in fittings to the fluid velocity by incorporating a fitting loss factor obtained from experimental test data.V fluid velocity, ft/secThe most common method for determining the contribution to the overall piping system of the fittings head lossis to convert the fitting head loss into an equivalent pipelength. As an example, use 60 F water as the workingfluid in a 3-inch diameter piping system with an internalflow of 10 ft/sec. The equivalent pipe length for a shortradius 90 elbow would be 6.9 feet for Red Thread IIand 5.9 feet for Centricast Plus CL-2030 . The two piping systems have different inner diameters that contribute to the differences in equivalent footage. Therefore,for best accuracy it is recommended that our computersoftware Success By Design be used to determine fittings equivalent piping footage.g acceleration of gravity, 32.2 ft/s2Typical liquid properties are presented in Table 1.2.Eq. 9Where:hf Fitting head loss, ft (m)k Flow resistance coefficientTABLE 1.1Flow Resistance coefficients for FittingsFitting/Size (In.)11½23468-1012-1618-24Short Radius 90º Elbow0.750.660.570.540.510.450.420.390.36Sweep Radius 90º Elbow0.370.340.300.290.270.240.220.210.19Short Radius 45º Elbow0.370.340.300.290.270.240.220.210.19Sweep Radius 45º Elbow0.200.180.160.150.140.130.120.110.10Tee Side Run1.381.261.141.081.020.900.840.780.72Tee Thru Branch0.460.420.380.360.340.300.280.260.24TABLE 1.2Typical Liquid PropertiesSpecific Gravity at 60ºFViscosity at 60ºF Centipoise10% Salt WaterBrine, 25% NaClBrine, 25% CaCl230º API Crude OilAverage Fuel OilsKeroseneAuto GasolineAviation Gasoline50% Sodium Hydroxide 2.4513.008.901.821.200.4695.00Mil 5624 Jet Fuels:JP3JP5JP80.750.840.800.792.141.40At 68ºF1.501.831.691.46At 68ºF6.4024.5012.001.94Type of LiquidAcids:60% Sulfuric (H2SO4)98% Sulfuric (H2SO4)85% Phosphoric (H2PO4)37.5% Hydrochloric (HCl)4

C. Open Channel FlowOne of the most widely used, formulas for open-channelflow is that of Robert Manning. This formula in Equation10 is useful in predicting the flow in open “gravity feed"fiberglass sewer lines. Our Success By Design softwareis recommended to perform these calculations.D. Gas FlowNOV Fiber Glass Systems piping systems can be usedin pressurized gas service when the pipe is buried atleast three feet deep.In above ground applications, they can beused provided the pressure does not exceedthe values shown below and further that thepipe is properly safeguarded when conveying ahazardous gas.Eq. 10Where:Q Flow rate in ft3/sec (m3/sec)A Flow cross sectional area, ft2 (m2)Rh Hydraulic radius, ft (m)S Hydraulic slope, dimensionlessS H/LH elevation change over the pipe length“L", ft (m)L Length measured along the pipe, ft (m)k 1.49 (US Customary units, ft. & sec.)k 1.0 for flow in m3/sec. Use meter for A,Rh, & D.n 0.009 Manning’s constant for fiberglassEq. 525149614" 16"54Consult your local representative for safeguard procedures.Since the inside diameter of the pipe is smoother andlarger than steel pipe of corresponding nominal diameters, less frictional resistance is developed under turbulent flow conditions, resulting in greater flow capacities.There are two basic equations used to calculate pressure loss for flow of gases. To determine which equationis required, the transition flow rate must be determinedfrom Equations 12, 13 and 14. If the desired flow rate isgreater than the value calculated from equation 14, thenthe equations for fully turbulent or rough pipe flow mustbe used. If the desired flow rate is less than the valuecalculated from equation 14, then the equation for partially turbulent or smooth pipe flow must be used.Equations for transition flow rate:Where:D Pipe inner diameter, ft (m)Θ Wet contact angle, radiansEq. 12Eq. 13Eq. 14Where QT Transition Flow RateFor fully turbulent or rough pipe flow:(1)Eq. 15(1) IGT Distribution Equations from American Gas Association Plastic PipeHandbook for Gas Service.5

orEq. 16For partially turbulent or smooth pipe flow(1)Eq. 17Where:Eq. 18D G L Pb Pi Po Q Tb T Z m K R m Inside Diameter (in.)Specific Gravity (S.G. of air 1.0)Length of Pipe Section (ft.)Base Pressure (psia)Inlet Pressure (psia)Outlet Pressure (psia)Flow Rate (MSCFH - thousand standard cubic ft.per hr.)Base Temperature ( R)Temperature of Gas ( R)Compressibility FactorViscosity (lb./ft. sec.)Absolute Roughness of Pipe 0.00021 (in.) for Fiber Glass Systems pipeRankine ( F 460 )(lb./ft. sec.) m (centipoise) 1488psia (Absolute) psig (Gauge) 14.7You can perform computer calculations using the Success ByDesign program to solve gas flow problems for: pipe size, Q,Pi, or Po if the other variables are known.TABLE 1.3 Typical Gas PropertiesType of GasAirCarbon DioxideCarbon MonoxideChlorineEthaneMethaneNatural GasNitrogenNitrous OxideOxygenSulfur DioxideSpecific Gravityat 60 F(1)Viscosity at 60 Flb./ft. 710.00000710.00001160.00000960.00001320.0000083(1) All Specific Gravity based on air 1.0 at 70 F.6

SECTION 2. Above Ground System Design - Supports, Anchors and GuidesPiping Support DesignAbove ground piping systems may be designed as restrainedor unrestrained. Selection of the design method is dependent on variables such as operating temperature, flow rates,pressures and piping layout. System designs combining thetwo methods often lead to the most structurally efficient andeconomical piping layout.Unrestrained System DesignThe unrestrained system is often referred to as a “simplesupported" design. It makes use of the inherent flexibilityof fiberglass pipe to safely absorb deflections and bendingstresses. Simple pipe hangers or steel beams are usedto provide vertical support to the pipe. These simple supports allow the piping system to expand and contract freely resulting in small axial stresses in the piping system.Long straight runs often employ changes-in-direction tosafely absorb movement due to thermal expansion andcontractions, flow rate changes, and internal pressure.Experience has shown the use of too many simple pipehangers in succession can result in an unstable line whencontrol valves operate and during pump start-up and shutdown. To avoid this condition the designer should incorporate guides periodically in the line to add lateral stability.In most cases, the placement of lateral guides at intervalsof every second or third support location will provide adequate stability. Axial stability in long pipe runs may beimproved by the proper placement of a “Pipe Hanger withAxial Guide" as shown in Figure 2.6. The project pipingengineer must determine the guide requirements for system stability.Restrained System DesignThe restrained system is often referred to as an “anchored and guided design". The low modulus of elasticity for fiberglass piping translates to significantly smallerthermal forces when compared to steel. Anchors areemployed to restrain axial movement and provide vertical support in horizontal pipelines. Anchors used torestrain thermal expansion create compressive forces inthe pipeline. These forces must be controlled by the useof pipe guides to prevent the pipe from buckling. In caseswhere axial loads created by anchoring a pipe run are excessively high, the use of expansion loops or expansionjoints must be employed. When using anchors, the effectof system contraction should be considered. See thethermal analysis section for more thorough informationon handling thermal loads.Fiberglass Piping System “Support"TerminologyFiberglass piping engineers use three basic structural components to design a piping system. They are the support,anchor and guide.SupportPipe supports hold the pipe in position and when properlyspaced prevent excessive deflections due to the weight ofthe pipe, fluid, external insulation and other loads.AnchorPipe anchors restrain axial movement and applied forces.These forces may result from thermal loads, water hammer,vibrating equipment, or externally applied mechanical loads.GuidePipe guides prevent lateral (side-to-side) movement of thepipe. Guides are required to prevent the pipe from bucklingunder compressive loading. For example: When anchorsare used to control thermal expansion, guides are alwaysrequired.A. Support DesignThe hanger support in Figure 2.0 must have sufficientcontact areas to distribute the load. The preferred circumferential load bearing contact is 180 . Refer to Table2.0 for minimum width requirements. When less than180 of circumference contact and/or larger diametersare encountered, support saddles as shown in Figure 2.1are recommended.Hanger fit on pipe should be snug but not tight.1”16Figure 2.0TABLE 2.0Minimum Support Width*Pipe Size Class I Class II(In.)(In.)(In.)111/223468101214*Note: Valid for Sg 211/22344677

Class I Products:CentricastPlus CL-2030,Centricast Plus RB-2530, Z-Core. Minimum recommended support saddle contact angle is 110 commodate pipe movements to prevent them from sliding offthe supports.B. Guide DesignClass II Products: Red Thread II, Green Thread,Silver Streak, F-Chem, CentricastCL-1520,Centricast RB-1520. Recommended support saddlecontact angle is 180 Support saddles are recommended for 16-24 inch diameter pipe. The pipe surface bearing stress should not exceed 50 lb/in2 for support designs.Typical Guide Usage1. Between anchors to prevent buckling of pipeline atelevated temperatures.2. Near entry points of expansion joints and loops toensure proper functionality.3. To provide system stability.Properly designed and installed guides prevent the pipe fromsliding off support beams and allow the pipe to freely move inthe axial direction. Guides should be used with 180 supportsaddles to reduce wear and abrasion of the pipe walls.Figure 2.1htLengSupport SaddleFigure 2.4U-Bolt GuideFlexible Clamp(1)Pipe1”16Contact An(1)Support SaddlegleTABLE 2.1RubberSaddle LengthPipe Size Class I Class 244468101214(1)(2)(1) Use the pipe diameter as minimum saddle length.(2) Refer to F-Chem product bulletin for sizes greater than 24-inchdiameter.Typical supports requiring support saddles are shown inFigures 2.2 & 2.3. The support saddles should be bondedto the pipe or held in place by flexible clamps. If clampedto filament wound pipe a 1/16" rubber pad should be placedbetween the pipe and the saddle. Saddle lengths should ac-(1) Not required if support saddle is bonded to pipe.Figure 2.4 shows a common method of guiding fiberglasspipe. A clearance of 1/16 to 1/8-inch is recommended between the guide and the support saddle. A 180 support“wear" saddle is recommended to prevent point contact between the U-bolt and pipe. The U-bolt should not be tightened down onto the pipe. It should be tightened to thestructural support member using two nuts and appropriatewashers. A 1/8-inch clearance is recommended between theU-bolt and the top of the pipe.Eight-inch diameter and larger pipe are generally allowedmore clearance than smaller sizes. The determination ofacceptable clearance for these sizes is dependent on thepiping system and should be determined by the project piping engineer.Figure 2.2Figure 2.3Another design practice is to use U-straps made from flatrolled steel instead of U-bolts. Flat U-straps are less aptthan U-bolts to “point" load the pipe wall. U-strap use is mostcommon when guiding pipe sizes greater than 6-inches diameter.8

Pipe Hanger with Lateral GuideMaximum rod length allowsfor axial movement18" minimumrod lengthSpacerLateralAuxiliaryGuideClamp, snugbut not tightFigure 2.5When U-bolts are used in vertical piping, then two 180 wear saddles should be used to protect the pipe aroundits entire circumference. It is appropriate to gently snugthe U-bolt if a 1/8-inch thick rubber pad is positioned between the U-bolt and the saddle. If significant thermalcycles are expected, then the U-bolts should be installedwith sufficient clearance to allow the pipe to expand andcontract freely. See the “Vertical Riser Clamps" sectionfor additional options in supporting vertical piping.Figure 2.5 shows a more sophisticated pipe hanger andguide arrangement. It may be used without wear saddlesas long as the tie rod allows free axial movement. Thehanger must meet the width requirements in Table 2.0. Ifa clamp width does not meet the requirements in Table2.0 or the pipe sizes are greater than 14-inch diameter,then support saddles should be used. See Table 2.1 forsupport saddle sizing recommendations.Lateral loading on guides is generally negligible undernormal operating conditions in unrestrained piping systems. In restrained piping systems, guides provide thestability required to prevent buckling of pipelines undercompressive loads. If the guides are located properly inthe pipeline, the loads required to prevent straight piperuns from buckling will be very small.Pipe Hanger with Axial Guide18" Minimum rod length allowsfor lateral flexibility.Figure 2.6 shows a pipe hanger with an axial guide usinga double bolt pipe clamp arrangement. This support provides limited axial stability to unrestrained piping systems.Pipe lines supported by long swinging hangers may experience instability during rapid changes in fluid flow.Stability of such lines benefit from the use of pipe guidesas shown in Figures 2.5 and 2.6.The support widths for guided pipe hangers should meetthe recommendations in Tables 2.0 & 2.1.Vertical Riser ClampsRiser clamps as shown in Figure 2.7 may act as simplesupports, aswell as guides,dependingRiser Clampupon how theyare attachedAnchorsleeveto the subor FRPstructure. Thebuildupclamp shouldbe snug butClamp, snugbut not tightnot so tight asto damage theSnug fitpipe wall. Theuse of an anFigure 2.7chorsleevebonded ontothe pipe is required to transfer the load from the pipe tothe riser clamp. See the “Anchor Designs" section for detailed information concerning the anchor sleeve or FRPbuildup.It is important to note that this type of clamp only providesupward vertical support. Certain design layouts and operating conditions could lift the pipe off the riser clamp.This would result in a completely different load distribution on the piping system. A pipe designer needs to consider whether the column will be under tension, or in astate of compression. Additional guides may be requiredto prevent unwanted movement or deflection.A qualified piping engineer should be consulted to ensurean adequate design.Axial GuideRiser clamps designed to provide lateral support shouldincorporate support saddles to distribute the lateral loads.SpacerC. Anchor DesignAnchor UsageClamp, snugbut not tightFigure 2.6Upset conditions can result in significant lateral loads onthe guides and should be considered during the designphase by a qualified piping engineer. Water hammer andthermal expansion or contraction may cause lateral loading on guides near changes in direction. Therefore, it isalways prudent to protect the pipe from point contact withguides near changes in directions and side runs.91. To protect piping at “changes-in-directions" from excessive bending stresses.2. To protect major branch connections from primary pipeline induced shears and bending moments.Particular consideration should be given to saddleand lateral fitting side runs.3. Installed where fiberglass

ments. Piping systems are available with liners of varying type and thickness, with molded, fabricated, or filament wound fittings, ranging in size from 1" to 72"(25 to 1800 mm) in diameter. tyPical aPPlicationS Fiberglass piping is used in most industries requiring cor-rosion resistant pipe. FRP piping is used in vent and liq-