Piping ComponentsAN INTRODUCTION

SUMMARY1. What is a Piping System?2. What are Piping Components?3. Piping Component Classification4. Typical Applications

Piping SystemConveys fluid between locationsPiping system includes:PipeFittings (e.g. elbows, reducers, branch connections, etc.)Flanges, gaskets, boltingValvesPipe supportsPiping system does not include:Support structuresEquipment

PipeA hollow cylinder or tube used to conduct a liquid, gas, or finely divided solidMaterials used for PipeSteel and Wrought Iron PipeUsed to carry water, steam, oil, and gasCommonly used under high pressures and temperaturesCast Iron PipeOften installed underground to carry water, gas, and sewageCopper tubingUsed in plumbing and heating and where vibration and misalignments are factors such as in automotive, hydraulic, and pneumatic designPlastic PipeOften used in chemical industry due to its resistance to corrosion and chemicalsNot recommended where heat or pressure is a factor

Pipe (continued)Pipe SizingPipe is normally identified by "nominal pipe size" or NPS and its wall thickness is referred to by schedule number or weightNPS maintains a uniform outside dia while varying the inside dia

Pipe (continued)Methods of Joining PipeButt-Weld JointLines NPS 2" and larger are usually butt-weldedUsed where connection will be permanent and on high pressure and temperature linesWeld metal may intrude inside of the piping. This may affect flow in services of fibrous material that may build up and clog the pipingSocket Welded or Screwed joint Used commonly on lines of NPS 1 " and smallerSocket welding is advantageous over screwed connections in that the absence of leakage is assuredNo chance of weld material entering the bore of the pipeThe 1/16" recess in the joint holds or pockets liquid

Pipe (continued)Methods of Joining PipeBolted flange jointUsed to bolt to flange nozzles on equipment and for process lines that require periodic inspection and/or cleaningMade by bolting together two flanges and have a gasket placed in between them to create a leak proof sealFlanges are expensive

Pipe FittingsProduce change in geometryFittings are used to:Change a pipe's directionConnect two or more pipesChange pipe sizeExtend or terminate pipe runsFittings that change a pipe's directionElbows (ells) Most common are 90 and 45 deg elbows, but are also available in 22 and 60 deg

Pipe Fittings (continued)Mitered Elbows Constructed as required from pipe and are not true fittingsUse is limited to low pressure lines 10" and larger where pressure drop is unimportantIn a 3 piece mitered, 90 degree elbow the flow resistance is double the resistance of a regular 90 degree continuous elbowBendsBends are constructed from straight pieces of pipeCommonly they are bends of 3 and 5 times the NPS of the pipe, referred to as 3R or 5R180 deg returnsUsually found in the construction of heating coils and vent on the top of storage tanks

Pipe Fittings (continued)Fittings that Connect two or more pipesTeesOffer the most varieties of any type of fittingFor reducing tees, the branch and/or one end of the thru section is a smaller diameter than the inlet

CrossesIf the branch line passes through the tee, the fitting becomes a Cross

WyesWyes are similar to tees except that the branch line is angled to reduce friction, typically at a 45-degree

Pipe Fittings (continued)Fittings that Connect two or more pipesOletsUsed as an alternative branch connection and do not require any reinforcementsMake a 90 degree branch as either full size or reduced off of a straight pipeWeldolets allow closer manifolding then tees permitThe socket weld version is called a sockolet and the threaded is called threadoletStub-inTerm used in welding a branch pipe run into the side of the main piping run, and is not a true fittingThe most common and cheapest approach for pipes 2" and larger

Pipe Fittings (continued)Fittings that change pipe sizeReducersUsed to join a larger pipe to a smaller pipeCan be couplings, tees, ells, or wyes, where one end is smaller than the otherBoth ends are femaleSwagesUsed to connect butt welded piping to smaller screwed or socket welded pipingBushingsServe the same purpose as reducers except that they have one male and one female endThey are virtually invisible once installed

Pipe Fittings (continued)Fittings that extend or terminate pipe runsCouplings Connect pipe to pipeUsually have tiny ridges or "stops" on the inside to seat the pipeAdaptersAre similar to couplings, but they connect different types of pipeUnions Are three-part mechanical fittings that connect any two standard size pipe in such a way that they may be disconnected and reassembled with a pipe wrenchCaps and Plugs End a run of pipe by closing it off with a leak tight seal

FlangesA flange allows two pipes to be mechanically connected together, or a pipe to be mechanically connected to a valve, tee or other piece of equipmentFlange PrincipalThe principle of a flange is to use a mechanical force (exerted by the bolts) to pre-load the gasket sufficiently so that when internal pressure is applied, there is enough contact stress between the flanges and gasket to maintain a seal.

Flanges (continued)Flange RatingIdentifies acceptable pressure/temperature combinationsFlange strength is based on dimensions and material usedSeven classes(150, 300, 400, 600, 900, 1,500, 2,500)Flange strength increases with class number

Flanges (continued)Flange FacingsThe most commonly used facings are:

Flange Types:Weld neck FlangeThe most common type of flange used for high pressure applicationsThey are recognized by their long tapered hub

Flanges (continued)Slip-On Flange Fits over the pipe and is then weldedRequires two weldsTheir calculated strength under internal pressure is approximately two-thirds that of welding neck flangesOnly available in smaller pressure ratings/diameters. Used in lieu of welding necks when cost or space is a major consideration.Socket Weld FlangeTheir internal pocket allows for a smooth bore and better fluid flow. They are ideal for small diameter high pressure applications.

Flanges (continued)Lap Joint FlangePrimarily employed with lap joint stubs Combined initial cost of the two items being approximately one-third higher than that of comparable welding neck flangesThe ability to swivel flanges and to align bolt holes simplifies the erection of large diameter or unusually stiff pipingThreaded FlangeConfined to special applicationsChief merit lies in the fact that they can be assembled without welding Are unsuited for conditions involving temperature or bending stresses of any magnitude, particularly under cyclic conditions where leakage through the threads may occur

Flanges (continued)Blind FlangeUsed to blank off the ends of piping, valves and pressure vessel openingBlind flanges, particularly in the larger sizes, are the most highly stressed of all flange typesOrifice FlangeUsed in conjunction with orifice meters for measuring the rate of flow of liquids and gasesAre basically the same as standard welding neck and slip-on flanges except for the provision of radial, tapped holes in the flange ring for meter connections and additional bolts to act as jack screws to facilitate separating the flanges for inspection or replacement of the orifice plate

Gaskets and BoltsGasketA sealing device used between two parts to prevent leakageMade from resilient material compressed by bolts to create sealTypes include inside-the-bolt circle (no bolt holes) and full face (with bolt holes and the same diameter as the flange) BoltA threaded fastenerProvides the required tension for making the seal

Valves

Pipe SupportsPipe hangers and supports are devices which transfer the loads from the pipe to the supporting structure or equipment

Pipe Support ConfigurationsPipe supports are designed to constrain pipe motion in one, two, or three space coordinatesCommon Pipe Support TypesSteel BracketA cantilever device intended for supporting a gravity loadU Bolt ClampA U-shaped rod with threaded ends used as a support or guide.

Pipe Supports (continued)Rod HangerProbably the most common type, that attaches to the pipe by a U bolt or clevis and clamps to structural steel aboveSteel Pipe ClampA pipe attachment for suspension of horizontal stationary insulated linesPipe ClipA pipe attachment for suspension of horizontal stationary lines by bolting the clip directly to a structure. Also referred to as a pipe strap or strapPipe SaddleA device having a curved base for cradling horizontal pipe

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