flanges and fittings types and classes

Note: The source of the technical material in this volume is the ProfessionalEngineering Development Program (PEDP) of Engineering Services.

Warning: The material contained in this document was developed for SaudiAramco and is intended for the exclusive use of Saudi Aramcosemployees. Any material contained in this document which is notalready in the public domain may not be copied, reproduced, sold, given,or disclosed to third parties, or otherwise used in whole, or in part,without the written permission of the Vice President, EngineeringServices, Saudi Aramco.

Chapter : Piping & Valves For additional information on this subject, contactFile Reference: MEX10104 K.S. Chu on 873-2648 or R. Hingoraney on 873-2649

Engineering EncyclopediaSaudi Aramco DeskTop Standards

Flanges And Fittings: Types And Classes

Engineering Encyclopedia Piping & Valves

Flanges & Fittings: Types & Classes

Saudi Aramco DeskTop Standards

CONTENTS PAGE

IDENTIFYING Types of Flanges and Fittings .................................................................1

Flange Assembly ...............................................................................................................1

Flange Types .....................................................................................................................2

Flange Attachment Types..................................................................................................3

Threaded Flanges ..............................................................................................................3

Socket-Welded Flanges.....................................................................................................4

Blind Flanges.....................................................................................................................5

Slip-on Flanges..................................................................................................................6

Lapped Flange ...................................................................................................................7

Welding-Neck Flanges ......................................................................................................8

Flange Facing Types .........................................................................................................9

Flange Gasket Types .......................................................................................................12

Sample Problem 1 ...........................................................................................................16

Solution ...........................................................................................................................16

Flange Standards .............................................................................................................17

ASME/ANSI B16.5 Flanges............................................................................................17

API 605 Flanges ..............................................................................................................18

MSS Flanges ...................................................................................................................18

ASME/ANSI B16.47.......................................................................................................19

Saudi Aramco Flanges.....................................................................................................20

Fitting Types....................................................................................................................22

Threading.........................................................................................................................22

Socket-Welded Fittings ...................................................................................................23

Butt-Welded Fittings .......................................................................................................24

Most Common Pipe Fittings............................................................................................25

Fitting Standards..............................................................................................................30

ANSI B16.9 .....................................................................................................................30

ANSI B16.11 ...................................................................................................................30

Other Fitting Standards....................................................................................................30



Saudi Aramco DeskTop Standards

Determining The Material Group for ASME/ANSI Flanges and Flanged Fittings .........32

The Materials Specification Table...................................................................................34

Material Groups...............................................................................................................34

Product Forms .................................................................................................................34

Saudi Aramco Practice ....................................................................................................34

Determining Flange and Fitting Rating Class..................................................................35

Flanges and Flanged Fittings...........................................................................................35

Pressure/Temperature Rating Tables ...............................................................................35

Selecting Pressure/Temperature Ratings for Butt-Welded, Socket

Welded and Threaded Fittings.........................................................................................40

Determining the Flange and Fitting Maximum Allowable Operating Pressure (MAOP)41

Conditions Beyond Normal Design Conditions ..............................................................41

WORK AID 1: Procedures for Determining the Material Group for

ASME/ANSI Flanges and Flanged Fittings ....................................................................42


Threaded, Socket-Welded, or Butt-Welded Fittings .......................................................43

WORK AID 2: Guidelines for Determining the Flange and Fitting Rating Class..........45

WORK AID 3: Procedures for Determining the Flange and

Fitting Maximum Allowable Operating Pressure (MAOP).............................................51


Butt-Welded Fittings .......................................................................................................51

Threaded and Socket-Welded Fittings ............................................................................51



Saudi Aramco DeskTop Standards 1

IDENTIFYING Types of Flanges and Fittings

This section describes the various flange types that are used in Saudi Aramco piping systems.

Flange Assembly

A flange is used to connect a pipe section to a piece of equipment, valve, or another pipe in away that will permit relatively simple disassembly. Such disassembly may be required formaintenance, inspection or operational reasons. Figure 1 shows a typical flange assembly.Flange assembly is normally used for pipe sizes above 38 mm (1-1/2 in.) NPS.

TYPICAL FLANGE ASSEMBLY

FIGURE 1




A flange assembly consists of:

Two flanges.

A gasket to provide a seal between the flanges.

Bolting to keep the assembly together.

One flange is attached to each of the items being joined. For example, a flanged valve maybe installed in a piping system, and the pipe ends on each side of it also will have flanges. Agasket is a resilient material that is inserted between the flanges and seated against the portionof the flanges called the face or facing. The gasket provides the seal between the fluid inthe pipe and the outside, and thus prevents leakage. Bolts compress the gasket to achieve theseal, and hold the flanges together against pressure and other loadings. There are severaltypes of flanges, flange attachment methods, flange facings, and gasket types.

Flange Types

There are several standard types of pipe flange. Two items must be specified to completelydefine a flange type.

Flange Type = Attachment Method + Face Type

A flange type is specified by stating the type of attachment and face. For example, "A weld-neck flat-faced flange." The type of attachment defines how the flange is connected to a pipesection or piece of equipment (such as a pressure-vessel nozzle). The type of flange face orfacing defines the geometry of the flange surface that contacts the gasket.




Flange Attachment Types

THREADED FLANGE

Source: ASME/ANSI B16.5 - 1988. With permission from the American Society of Mechanical Engineers

FIGURE 2

Threaded Flanges

A threaded flange has pipe threads machined into its bore as shown in Figure 2. The flange isscrewed to matching threads on the pipe end.

Threaded flanges are used only for small-diameter piping systems, up to 50 mm (2 in.) NPS(nominal pipe size), at locations where pipe disassembly may be required for maintenance,field modifications, or to match specialty fittings and valves.

For hazardous services, a threaded flange may only be used up to 38 mm (1-1/2 in.) NPS.However, based on Saudi Aramco Engineering Standard SAES-L-009, Metallic Flanges,Gaskets, and Bolts, welded slip-on-type flanges are preferred over threaded flanges inscrewed piping systems. Threaded flanges, and threaded piping systems in general, are notemployed in larger diameters because of the increased difficulty of obtaining sufficient anduniform thread engagement. The preference for slip-on rather than threaded flanges is basedon the greater likelihood of having a leak in a threaded-flange attachment joint.




SOCKET-WELDED FLANGE


FIGURE 3

Socket-Welded Flanges

A socket-welded flange has an oversized bore that is partially machined into the end oppositethe face, as illustrated in Figure 3. The pipe is inserted into this "socket" and the flange filletis welded to the pipe OD. The section of this module that discusses socket-welded fittingsdescribes socket-welded attachments in more detail.

Based on Saudi Aramco Engineering Standard SAES-L-010, Limitations on Piping Joints, themaximum size of socket-welded joints in hazardous services shall be 38 mm (1-1/2 in.) NPSfor new construction. A maximum 50 mm (2 in.) NPS may be used for maintenance, minorfield modifications of existing systems, and when needed to match existing equipmentconnections. However, as with threaded piping systems, SAES-L-009 indicates that weldedslip-on-type flanges are preferred over socket-welded flanges in socket-welded pipingsystems. Here again, this preference is based on the assumed greater reliability of a slip-onversus a socket-welded-type flange attachment.




BLIND FLANGE


FIGURE 4

Blind Flanges

A blind flange, as shown in Figure 4, is a flat metal plate that is used to block flow in a pipingsystem.

A blind flange is included here for completeness. However, it is not attached to the pipe, butbolted to a mating flange. It is used when a pipe end or equipment nozzle must be blockedfrom flow, but there still must be an easy means of internal access.




SLIP-ON FLANGE


FIGURE 5

Slip-on Flanges

A slip-on flange, as shown in Figure 5, has an oversized bore. It is slipped over the pipe ODand projects slightly beyond the pipe end. The flange is then fillet welded to the pipe OD, andalso between the flange bore and the pipe end.

Slip-on flanges are typically a lower cost alternative to the welding-neck-type flange that willbe described below. This is because a slip-on flange is lighter (i.e., uses less material) andrequires less welding to attach it to the pipe. However, a slip-on flange is not suitable forhigh-temperature, cyclic, high-pressure or high external loading situations.

Based on SAES-L-009, Saudi Aramco requires that an ASME Code Section VIII, Division 1flange analysis be performed if a slip-on flange is used for any of the following cases:

Severe cyclic conditions (i.e., large and frequent temperature fluctuations, or vibration-prone services).

Design temperature greater than 230C (450F).

ANSI Class 400 or higher rating.

Pipe size over 600 mm (24 in.).

The flange analysis must consider thermal and other external piping loads, and mustdemonstrate that the flange will not be over stressed. Because of this extra analysisrequirement, it is unlikely that a slip-on-type flange will be used in these services because itseconomic attractiveness will be reduced.




LAPPED FLANGE


FIGURE 6

Lapped Flange

A lapped flange, as shown in Figure 6, is not physically connected to the pipe. It is slippedover a pipe stub that has a flared end, and the pipe stub is welded to the major pipe section.The flared pipe end has a machined face where the gasket is seated. The bolting holds theflanges and gasket joint together.

Based on SAES-L-009, Saudi Aramco prohibits the use of lap-joint flanges in severe cyclicconditions. Their use is also limited to special applications such as:

To avoid welding dissimilar materials.

To facilitate lining up the bolt holes in underwater flanged joints. The nature of a lap-joint flange allows it to be easily rotated to facilitate bolt-hole alignment because it is notpermanently attached to the pipe.

A lapped-flange assembly is less able than other attachment types to absorb loads from apiping system because there is no connection between the flange and the pipe. Therefore, thecapability to absorb loads must be considered in the overall system design. The use of lap-joint flanges is the exception rather than the rule. The main advantage of a lapped flange iscost, and then only in high-alloy piping systems. No part of a lapped flange contacts theprocess fluid. Therefore, in high-alloy piping systems, a lapped flange may be made fromless costly carbon steel material.




WELDING-NECK FLANGE


FIGURE 7

Welding-Neck Flanges

A welding-neck flange, as shown in Figure 7, is the strongest of the standard flangeattachment types. The end of the flange is butt-welded to the end of the pipe. The flangebore is sized to match the pipe bore.

A welding-neck flange is the most widely used in refinery services because of its greaterstrength and ability to be used at high temperature and in cyclic service. However, it is themost expensive of the various flange attachment types because it is the heaviest (i.e., uses themost material) and requires the most welding to attach to the pipe end. Based on SAES-L-009, this is the preferred flange type in metallic piping systems, 50 mm (2 in.) NPS andabove.




Flange Facing Types

The area of a flange where the gasket is positioned is called the face or facing. The threeprimary flange facings are the flat face, raised face and ring joint. Any of the flangeattachment types that were described above, except for the lapped flange, may use any ofthese facings. The facing for a lapped flange is located on the flared pipe stub end, not on theflange.

FLAT-FACED FLANGE

Flat Face

FIGURE 8

Flat-Faced Flanges In the flat-faced flange shown in Figure 8, the area where the gasket islocated is at the same elevation as the surrounding flange surface.

A flat face is typically used only for cast or ductile iron flanges, with relatively low-strengthmaterial, or when a steel flange must mate to such a flange.

There is no change in elevation in proceeding from the flange inside diameter to its outsidediameter. This provides uniform flange contact with the gasket over a large surface, andlimits local flange bending that is caused by bolt load. Minimization of flange bending isnecessary for cast iron, ductile iron, or other relatively low-strength materials, but not for steelflanges. Therefore, there are few applications for flat-face flanges in refinery orpetrochemical services because there are relatively few applications where such low-strengthflange materials are acceptable. Sheet-type gaskets that extend from the flange insidediameter to the outside diameter (i.e., full face) typically are used with flat-face flanges.

Based on SAES-L-009, a flat-faced flange with a full-face gasket shall be used when one orboth of the mating flanges is cast iron, aluminum, plastic, or any other material that could beoverstressed by the bolt load.




RAISED-FACE FLANGE

Raised Face

FIGURE 9

Raised-Face Flanges A raised-face flange is shown in Figure 9. The area where the gasketis located is higher than the surrounding flange surface, typically by 1.5 mm (1/16 in.). Thisraised-face portion of the flange has a specially machined, serrated finish that is suitable forthe typical gasket types used in process plant applications. Any gasket type, other than a ringtype, may be used with a raised-face flange. The raised face results in much less contact areaand higher gasket contact stresses as compared to a flat face. The gasket is compressed andsealed only in the area of the raised face.

A raised-face flange is used for a very broad range of services, and is the most common type.

Based on SAES-L-009, a raised-face flange is required for steel flanges through Class 600and/or a maximum design temperature of 480C (900F), except for underwater service. Asmooth machine finish, 3.2-6.4 micrometer AARH (arithmetic average roughness height),should be specified for use with spiral-wound gaskets.




RING JOINT

23

Radius

FIGURE 10

Ring-Joint Flanges A ring-joint flange face, as shown in Figure 10, consists of a groovethat is machined into the flange end. The sealing surfaces of the groove are smoothly finishedto 63 micro inch surface roughness, and are free of any detrimental ridges or tool marks. Thepresence of such surface defects will result in a leaking joint, since a very smooth contactsurface is required to achieve a leak-proof, metal-to-metal seal. A solid metal ring-typegasket is inserted in the groove.

The ring-joint flange is used for the most severe service applications where the other possibleflange face and gasket combinations will not provide acceptable performance. Typically,these are high-pressure and/or high-temperature services.

Based on SAES-L-009, a ring-joint flange is required for steel flanges of Class 900 andhigher, for design temperatures over 480C (900F), or for underwater pipelines in Class 300and higher.




Flange Gasket Types

The gasket provides the seal in a flange assembly. The three general gasket types that aretypically used in pipe flanges for process plant and pipeline applications are:

Sheet.

Spiral wound.

Solid metal ring.

A wide variety of materials are available for each of these gasket types to suit particularservice requirements.

Sheet Gaskets The most common material used for sheet gaskets is compressed asbestos.However, there has been increasing concern regarding the ultimate availability of sheetasbestos gaskets due to potential worker health and materials disposal issues. Asbestosgaskets will no longer be available within several years, and the use of asbestos should beavoided whenever a suitable substitute is available. Several alternative sheet gasket materialshave been introduced in recent years. Many of these use synthetic fibers rather than asbestos,along with an elastomeric binder. The binder is a larger percentage of the sheet material inthese synthetic fiber gaskets, and thus is a more significant factor in determining acceptableapplications. Nonasbestos sheet gaskets that utilize synthetic fiber with a binder will typicallyhave a lower maximum operating temperature than a compressed asbestos gasket. Of equalimportance is that they will have much less fire resistance than an asbestos gasket, so thatgreater flange leakage could be expected should a fire occur in the vicinity of a flange with asynthetic fiber sheet gasket.

Another nonasbestos sheet-gasket material is composed of flexible graphite. The best flexiblegraphite sheet-gasket-types also employ a stainless steel sheet insert with the flexible graphitefor increased strength. This gasket material has exhibited excellent corrosion resistance inmost process plant applications, and has provided good performance at elevated temperatures.




Sheet gaskets may be used with flat or raised-face flanges. Sheet gasket selectionrequirements are based on SAES-L-009 as follows:

Compressed synthetic fiber sheet gaskets with an oil-resistant binder, 1.6 mm (0.063 in.)thick, may be used for Class 150 flanges in nonhazardous services up to 230C (450F).An example of their use is in lube oil piping.

Synthetic rubber gaskets, ASTM D1418 Class CSM, shall be used for all acid servicesexcept nitric acid and oleum. For nitric acid and oleum, ASTM D1418Class FKM elastomer shall be used for flat-face flanges.

Elastometric material, 3 mm (1/8 in.) thick, with a Shore A durometer hardness ofbetween 50 and 60, shall be used for full-face gaskets for plastic flanges. For wetchlorine or hypo chlorite services, the elastomer shall be ASTM D1418 Class CSM.




CROSS-SECTION OF SPIRAL-WOUND GASKET

FIGURE 11

Spiral-Wound Gaskets A spiral-wound gasket is manufactured by alternately winding stripsof metal and soft filler material around a mandrel. This is illustrated in Figure 11.

Most spiral-wound gaskets that are used for piping applications are supplied with an outermetal guide or retaining ring. The retaining ring outside diameter is typically sized to justcontact the flange bolts, and thus serves as a gasket alignment aid. The retaining ring alsoacts as a compression limit stop to prevent overcompressing the gasket material during flangeboltup. Sometimes, an inner retaining ring is also supplied, as shown in Figure 11. The innerring improves stability for either larger gasket sizes or for weaker filler materials, such asTeflon.

The standard spiral-wound gasket employs Type 304 stainless steel metal windings withasbestos filler. However, other winding and filler materials are available to suit particularservice needs.

Spiral-wound gaskets are the standard for use with raised-face flanges. Specially sized spiral-wound gaskets are also available for retrofit into ring-joint-type flanges when there is such aneed.

Spiral-wound gaskets tend to be used at higher temperatures and pressures than sheet gasketmaterials because they are stronger.




Spiral-wound gasket selection requirements are based on SAES-L-009 as follows:

Spiral-wound Type 316 stainless-steel gaskets with a flexible graphite filler and a carbonsteel guide ring are used with raised-faced flanges in most services. This includes mostprocess hydrocarbon and steam services. In an oxidizing environment, the maximumuse temperature is limited to 454C (850F).

For operating temperatures below -45C (- 50F), the guide ring shall be Type 304stainless steel.

Metal Ring-Joint Gaskets come in two basic shapes, an oval cross-section and an octagonalcross-section. The octagonal ring seals by surface wedging contact with the flange groove,and the oval ring seals by line contact. Therefore, the oval ring is somewhat more tolerant ofslight flange misalignments than the octagonal ring, and still provides a tight seal. Inaddition, the same bolt load will result in a higher local gasket contact stress and thus apotentially tighter joint with an oval ring. Also, an octagonal ring cannot fit into older ring-joint flanges that have a round bottom groove.

Ring-joint gaskets are typically softer than the flange grooves. Therefore, the gasket, ratherthan the groove, will deform slightly under the applied bolt load. A variety of ring materialsare available to suit the particular service needs. The most common materials are iron or softsteel, 4-6% chrome, and stainless steels.

A solid metal ring-type gasket is used only with ring-joint-type flanges. Ring-joint gasketselection requirements are based on SAES-L-009 as follows:

Soft iron, octagonal ring-joint gaskets shall be used with ASME/ANSI B16.5, MSS-SP-44, or Saudi Aramco standard ring-joint flanges.

For ASME/ANSI B16.5 ring-joint flanges in corrosive services, a low-carbon steel,octagonal ring-joint gasket with a Buna-N rubber inner V-Type guard and outer molded-on ring guard shall be used.

For API 6A flanges, low-carbon steel, octagonal, pressure energized ring-joint gasketsin accordance with API 6A Type RX shall be used.




Sample Problem 1

It is necessary to install a new pressure vessel at an existing Saudi Aramco plant. The flangeand facing type and the gasket must be specified for this application. The necessary designinformation is as follows:

The pressure vessel is carbon steel and is in a dangerous hydrocarbon service at a designtemperature of 371C (700F). The design pressure is 3,448 kPa (500 psig), an ASME/ANSIClass 300 carbon steel flange is required, and the pipe size is 200 mm (8 in.).

Solution

Since the material is not low strength, such as cast iron, a flat-face flange is not required. Theservice conditions are not severe enough to require a ring-joint flange. Therefore, a raised-face flange should be used. The choices for flange attachment type are immediately narroweddown to slip-on or weld-neck types due to the 200 mm (8 in.) pipe size. Because the designtemperature exceeds 232C (450F), a weld-neck flange should be used to avoid the flangeanalysis required by SAES-L-009.

Since the design temperature exceeds 232C (450F), and the ANSI Class exceeds 150, andthis is a dangerous hydrocarbon service, sheet gaskets cannot be used. Because the flangesare raised face, ring-joint gaskets cannot be used. Therefore, spiral-wound gaskets with Type316 stainless-steel windings, a flexible graphite filler, and a carbon steel guide ring arerequired, based on SAES-L-009.

The complete solution to this problem is to use raised-face weld-neck flanges with a spiral-wound gasket that has Type 316 stainless-steel windings, a flexible graphite filler, and acarbon steel guide ring.




Flange Standards

Saudi Aramco uses industry standards to define which flanges are used in Saudi Aramcopiping systems. Piping is typically sized and purchased to meet standard diameters. Becausestandard pipe sizes are used, it is practical to have standard flange sizes and dimensions.

There are four industry standards, a Saudi Aramco Engineering Standard, and a SaudiAramco Material System Specification that cover flanges:

ASME/ANSI B16.5 flanges.

API-605 flanges.

MSS flanges.

ASME/ANSI B16.47 flanges.

Saudi Aramco Special Flanges, as specified by standard drawings listed in SAES-L-009.

02-SAMSS-011.

ASME/ANSI B16.5 Flanges

ASME/ANSI B16.5, Pipe Flanges and Flanged Fittings, provides flange dimensional detailsand pressure/temperature ratings for standard pipe sizes from 13 through 600 mm (1/2through 24 in.). This Standard covers a wide range of material types, and will typically be theflange standard used for process plant applications.

The pressure/temperature ratings that are contained within ASME/ANSI B16.5 specify thecombinations of pressure and temperature that are acceptable for given flange sizes anddimensions. The term class is used to designate groupings of acceptable pressure/temperaturecombinations contained within ASME/ANSI B16.5. ASME/ANSI B16.5 contains sevenclasses designated as classes 150, 300, 400, 600, 900, 1500, and 2500. As the number of theclass increases, the strength of the flanges within it increases. Therefore, higher flange classescan withstand higher pressure/temperature combinations. Determination of the appropriateflange class will be discussed later in this module.




Saudi Aramco Engineering Standard SAES-L-009, Metallic Flanges, Gaskets and Bolts,contains the following requirements regarding the use of ASME/ANSI B16.5 flanges:

ASME/ANSI B16.5 classes 150, 300, 600, 900 and 1500 shall be used for carbon andalloy steel flanges in 13 through 600 mm (1/2 through 24 in.) nominal pipe sizes. Itshall be used for Class 2500 in nominal sizes 13 through 300 mm (1/2 through 12 in.).

Class 400 carbon steel flanges shall not be used for nominal sizes of less than 750 mm(30 in.).

API 605 Flanges

API 605 encompasses raised-face carbon steel welding-neck flanges in 650-1,500 mm (26-60in.) nominal pipe sizes with pressure ratings corresponding to classes 75, 150, 300, 400, and600. It also includes a class 900 for welding-neck flanges in 650-1,200 mm (26-48 in.)nominal pipe sizes. Finally, it also specifies flanges that are cast or forged as the integral endsof valves, fittings, or nozzles for classes 75, 150, or 300.

API 605 begins where ASME/ANSI B16.5 stops in terms of pipe size. However, it does notreach the maximum pressure/temperature ratings of ASME/ANSI B16.5, nor does it covermaterial other than carbon steel. Based on SAES-L-009, API-605 flanges may be used foronly class 75 in sizes of 650-900 mm (26-36 in.) in 50 mm (2 in.) increments, and sizes1,050-1,500 mm (42-60 in.) in 150 mm (6 in.) increments.

MSS Flanges

MSS standards are developed and revised by the Manufacturers Standardization Society ofthe Valve and Fittings Industry. MSS-SP-44, Steel Pipe Line Flanges, originally wasdeveloped to establish uniform flange dimensions for use with high-pressure pipelines of 650through 1,500 mm (26 through 60 in.) size in pressure classes of 300 through 900. It laterwas revised to include sizes down to 300 mm (12 in.) and Class 150. The flange designs areintended primarily for use with API 5LX line pipe, and they are proportioned accordingly.Their design reflects also the higher design stresses that are permitted in pipeline service.




There is a basic difference between ASME/ANSI B16.5 and MSS-SP-44 flanges.ASME/ANSI B16.5 flanges originally were designed for attachment to relatively thick-walledpipe. However, the larger diameter SP-44 flanges have hubs that specifically are designed forattachment to relatively thin-walled, high yield-strength pipe.

The "x" grades of the API 5L pipe material specification have relatively high yield strengths.Special attention should be paid to situations where an ASME/ANSI B16.5 flange is attachedto a thin-walled pipe operating near the maximum atmospheric temperature/pressure rating ofthe flange, or where an SP-44 flange is attached to a relatively thick-walled pipe. The stressat the flange-hub attachment point should be checked in each of these cases to ensure that it isnot excessive.

MSS-SP-44 flanges may be used within the following limitations, in accordance with SAES-L-009:

Classes 150, 300, 400, 600, and 900 for nominal pipe sizes of 300-600 mm (12-24 in.)for welding-neck flanges with single-taper hub only.

Classes 400 and 600 for pipe sizes of 1,250-1,500 mm (50-60 in.), welding-neck andblind flanges, raised face only.

Class 900 for pipe sizes 650 through 1,200 mm (26 through 48 in.), welding-neck andblind flanges.

ASME/ANSI B16.47

ASME/ANSI B16.47, Large-Diameter Steel Flanges, is essentially a combination of the API605 and MSS SP-44 flanges. ASME/ANSI B16.47 covers pipe flanges in 650 through 1,500mm (26 through 60 in.) nominal sizes in ratings corresponding to classes 75, 150, 300, 400,600 and 900. MSS SP-44 flanges are designated as Series A flanges, and API 605 flanges aredesignated Series B. The materials that are covered by ASME/ANSI B16.47 are the same asthose in ASME/ANSI B16.5, except that nickel-base alloys are excluded.Pressure/temperature ratings are consistent with ASME/ANSI B16.5.

02-SAMSS-011, Forged Steel Weld-Neck Flanges for Low - and Intermediate-TemperatureService, permits the use of ASME/ANSI B16.47 flanges, Series B, Class 75 for sizes that arenot covered by Saudi Aramco Standard Drawings.




Saudi Aramco Flanges

SAES-L-009 specifies standard flange material specifications based on design temperatureand strength requirements, as outlined in Work Aid 1. The use of ASTM A105 and A694flange materials is restricted due to their poor experience in Saudi Aramco. Flange materialspecifications for pipeline applications are selected to be of comparable strength to that of theconnected pipe. For example, if the pipe material that is used has a 290 MPa (42,000 psi)SMYS, the flange material has an F42 strength designation.

SAES-L-009 also lists standard Saudi Aramco drawings that provide mandatory dimensionalstandards for specific size ranges, ratings, flange types, and facings. These standard flangesmust be used as applicable within their defined scopes, even if API-605, MSS-SP-44, orASME/ANSI B16.47 has the same designations. These standard drawings are as follows:

NPS Range Class Type FacingStandardDrawing

26-60 150 WN RF AD-03663426-60 300 WN RF AD-03699126-48 300 WN RJ AC-03648454-60 300 WN RJ AC-03643730-48 400 WN RF AD-03669826-48 600 WN RF AD-03667326-48 600 WN RJ AC-03644226-48 300 Lap RJ AC-03648654-60 300 Lap RJ AE-03643826-48 600 Lap RJ AC-03644354-60 75 Blind RF AD-036696

where: WN = Weld neck.RF = Raised face.RJ = Ring joint.Lap = Lapped flange.Blind = Blind flange.




02-SAMSS-011 , Forged Steel Weld-Neck Flanges for Intermediate-Temperature Service,provides Saudi Aramco purchase requirements for forged steel weld-neck flanges in low- andintermediate-temperature services. Services that have design temperatures above 425C(800F) or below -60C (-75F), or those that require the use of higher alloy pipe material, arenot covered by this SAMSS and must be handled as special cases.

02-SAMSS-011 was first issued in February, 1994 and supersedes Standard Drawing AB-036028. It expands upon the flange material selection requirements that are specified inSAES-L-009 and the requirements that are specified in the relevant industry standards. Theseadditional Saudi Aramco requirements are meant to ensure higher overall flange materialquality based on past experience, and to minimize the probability of experiencing problemsduring piping system fabrication and operation.

02-SAMSS-011 adds additional restrictions on material usage, and further requirements in thefollowing areas:

Flange manufacturing details.

Maximum hardness limitations.

Heat treatment.

Material chemistry.

Mechanical strength testing.

Impact testing.

Hardness testing.

Nondestructive examination.

Repairs.

Markings.

Painting and shipping.

Participants are referred to 02-SAMSS-011 for specific details.




Fitting Types

Pipe fittings are used to make some change in the geometry of a piping system. This changecould include:

Modifying the flow direction.

Bringing two or more pipes together.

Altering the pipe diameter.

Terminating a pipe.

Three attachment methods may be used for fittings:

Threading.

Socket-welded.

Butt-welded.

These are the same alternatives that are available for flange attachment, as was discussedpreviously.

Threading

A threaded fitting has pipe threads machined into its bore. The fitting is screwed intomatching threads on the pipe end.




SOCKET-WELD ATTACHMENT DETAIL

t = Nominal Pipe Wall Thickness

C x (Min) = 1.25t But Not Less

Than 4.0 mm (0.16 in.)

Approx. 1.5 mm (0.06 in.) Before Welding

FIGURE 12

Socket-Welded Fittings

A socket-welded-type fitting attachment is designed with a recess in its end to permit the pipeto be inserted, as shown in Figure 12. The pipe is withdrawn approximately 1.5 mm (1/16 in.)from the bottom of the recess, then fillet welded between the pipe outside diameter and theend of the fitting. The gap is needed in order to provide space to permit differential thermalexpansion which occurs both during welding and normal operation. Without this gap, theattachment fillet weld can crack due to the load applied by the pipe when it expands into therecess due to differential thermal expansion.




A socket-welded or threaded coupling or half-coupling is primarily used to make anattachment between a 38 mm (1-1/2 in.) or smaller diameter pipe and a larger diameterheader. A coupling is also sometimes used to connect two small diameter pipe sections,rather than butt welding them together.

Use of Threaded or Socket-Welded Fittings Based on SAES-L-010, threaded- or socket-welded-type fittings are normally permitted through 38 mm (1-1/2 in.). NPS for newconstruction in hazardous services. They may be used up to 50 mm (2 in.) NPS in hazardousservices if necessary for maintenance, minor field modifications of existing systems, or whenneeded to match existing equipment connections. In nonhazardous services, threaded fittingsmay be used through 75 mm (3 in.) NPS for standard fittings, and through 100 mm (4 in.)NPS when connecting to special items such as fire hydrants.

Butt-Welded Fittings

Butt-welded-type fittings are used in pipe sizes 50 mm (2 in.) NPS and above. As their nameimplies, they are welded directly to the connecting pipe sections by using full-penetration buttwelds. Figures 13 through 18 show sketches of typical butt-welded fittings.

These same types of fittings may also be supplied with threaded or socket-welded endconnections. Threaded or socket-welded fittings are used in the same applications but insmaller pipe diameters, as previously discussed.




ELBOW AND RETURN

FIGURE 13

Most Common Pipe Fittings

An elbow or return changes the direction of a pipe run. Standard elbows change the directionby either 45 or 90. Returns change the direction by 180. Long-radius elbows have a bendradius of 1-1/2 times the nominal pipe size, and short-radius elbows have a bend radius equalto the nominal pipe size.

The long-radius elbow is more commonly used. Short-radius elbows are normally only usedif there is a space restriction for the piping system layout. The wall thickness of an elbow willtypically be identical to that of the adjacent pipe sections, since it is normally made fromcomparable material.




TEE

FIGURE 14

A tee, as shown in Figure 14, provides for the intersection of three sections of pipe. A straighttee has equal diameters for both the run and branch pipe connections. A reducing-outlet teehas a branch diameter which is smaller in size than the run diameter. A cross is a special typeof tee which permits the intersection of four sections of pipe. A cross is rarely seen in processplant applications. Tees are designed with extra thickness in the area where the branchconnects with the run. This is to provide reinforcement to compensate for the strengthreduction that is caused by the hole cut in the run. The general subject of branch connectionreinforcement is discussed in MEX 101.05.

LATERAL TEE

FIGURE 15

A lateral, as shown in Figure 15, is a special type of tee. In this case, the branch connectionenters the header at an angle, normally 45.

A lateral is used in situations where it is necessary for the two flow streams to combine in aless abrupt transition than provided by a standard 90 tee.




TYPICAL WELDING OUTLET FITTING OR INTEGRALLY REINFORCEDBRANCH CONNECTION

Branch

Run Pipe

FIGURE 16

A welding outlet fitting , or integrally reinforced branch connection, shown in Figure 16, isanother method of fabricating an intersection between two sections of pipe. This type offorged fitting is designed such that all the reinforcement required to strengthen the opening iscontained within the forged fitting itself. The hole is cut in the header pipe and the fitting isthen welded to it. There are two types of attachment used in these fittings. In one, the fittingabuts the outside diameter of the header and is welded to it using a full-penetration weldthrough the fitting thickness. This is the type shown in Figure 16. In the second, the hole iscut a little larger, the fitting is inserted into the header wall, and then is butt-welded into it.

A welding outlet fitting is often a less expensive alternative to a butt-welding tee, and is oftenused as a substitute. It also may be the preferred option when designing branch connectionsinto large-diameter headers for high-pressure or high-temperature conditions, rather thanusing welded-on reinforcement pads.




REDUCER

Concentric Eccentric

FIGURE 17

A reducer, illustrated in Figure 17, changes the diameter in a straight section of pipe, and comesas either a concentric or eccentric type. The centerlines of the large and small diameter endscoincide in a concentric reducer, whereas they are offset in an eccentric type. Eccentricreducers simplify the support-point structural design of horizontal pipe runs by keeping bothpipe diameters at the same bottom-of-pipe elevation. The wall thickness of a reducer willtypically be identical to that of the adjacent pipe sections, since they are made of comparablematerial.

CAP

FIGURE 18

A pipe cap, as shown in Figure 18, is used to close off the end of a pipe section. This isanalogous to the head on a pressure vessel. A pipe cap rather than a blind flange is used insituations where it is known that the pipe end will not have to be opened. The wall thicknessof a butt-welded pipe cap will typically be identical to that of the adjacent pipe section. Apipe plug serves the same purpose in a threaded or socket-welded piping system.




LAP-JOINT STUB END

FIGURE 19

A lap-joint stub end , as shown in Figure 19, is used in conjunction with lap-joint flanges. Thelap-joint flange is first slipped over the stub end, and the stub end is then butt welded to theend of the pipe section. Here again, the wall thickness of the stub end will typically matchthat of the adjacent pipe.




Fitting Standards

The two primary design standards that are used for pipe fittings are:

ANSI B16.9, Factory-Made Wrought Steel Butt-Welding Fittings.

ANSI B16.11, Forged Steel Fittings, Socket-Welding and Threaded.

ANSI B16.9

ANSI B16.9 encompasses overall dimensions, tolerances, ratings, testing and markings forwrought carbon and alloy steel factory made butt-welded fittings of 13 through 1,200 mm (1/2through 48 in.) NPS. ANSI B16.9 includes fittings of any wall thickness that may beproduced, except low-pressure corrosion-resistant fittings. These latter items are covered byMSS SP-43, Wrought Stainless Steel Butt-Welding Fittings.

ANSI B16.11

ANSI B16.11 encompasses pressure/temperature ratings, dimensions, tolerances, marking,and material requirements for forged carbon and alloy steel socket-welded and threadedfittings in sizes 3 through 100 mm (1/8 through 4 in.). Such fittings include elbows, tees,crosses, couplings, half-couplings, caps, plugs, and bushings.

Other Fitting Standards

The following lists other fitting standards that are used and their applications

Standard Application

ANSI A21.14 Ductile Iron Fittings, 3 Through 24 in., for Gas.

ASME/ANSI B16.3 Malleable Iron Threaded Fittings, Class 150 and 300.

ASME/ANSI B16.4 Cast Iron Threaded Fittings, Class 125 and 250.

ASME/ANSI B16.15 Cast Bronze Threaded Fittings, Class 125 and 250.




Standard Application

ASME/ANSI B16.28 Wrought Steel Butt-Welding Short-Radius Elbows andReturns.

ASME/ANSI B16.39 Malleable Iron Threaded Pipe Unions, Class 150, 250 and300.

AWWA/ANSI C110 Ductile-Iron and Gray-Iron Fittings, 3 Through 48 in., forWater and Other Liquids.

AWWA/ANSI C208 Dimensions for Steel Water Pipe Fittings

MSS-SP43 Wrought Stainless Steel Butt-Welding Fittings

MSS-SP75 Specifications for High-Test Wrought Butt-WeldingFittings.

MSS-SP83 Carbon Steel Pipe Unions, Socket-Welding andThreaded.

ASME - American Society of Mechanical Engineers.

ANSI - American National Standards Institute.

AWWA - American Water Works Association.

MSS - Manufacturers Standardization Society of the Valve and Fittings Industry.




Determining The Material Group for ASME/ANSI Flanges and Flanged Fittings

The next step in specifying a flange or flanged fitting is to select the material specification andgroup number, which are needed to select the class or rating of the flange or flanged fitting.This section discusses the selection of flange materials specification and material groupnumber. Flange material specifications are listed in Table 1A of ASME/ANSI B16.5. Aportion of this Table is reproduced as Figure 20. Material selection for threaded, socket-welded, and butt-welded fittings is not as involved but also will be discussed.

Work Aid 1 summarizes the flange material selection process, the use of SAES-L-009 inselecting flange material specifications, and how to use the Materials Specifications Table.




ASME/ANSI B16.5 TABLE 1A MATERIAL SPECIFICATIONS

Material Groups Product FormsMaterial Nominal Forgings Castings Plates

Group No. DesignationSteel

Spec.No. Grade Notes



1.1 Carbon A 105 (1)(2) A 216 WCB (1) A 515 70 (1)A 350 LF2 A 516 70 (1)

C-Mn-Si A 537 Cl.1 1.2 Carbon A 216 WCC (1)

A 352 LCC

2 1/2 Ni A 352 LC2 A 203 B

3 1/2 Ni A 350 LF3 A 352 LC3 A 203 E 1.3 Carbon A 352 LCB (1) A 515 65 (1)

A 516 65 (1)

2 1/2 Ni A 203 A

3 1/2 Ni A 203 D 1.4 Carbon A 350 LF1 A 515 60 (1)

A 516 60 1.5 C-1/2 Mo A 182 F1 (3) A 217 WC1 (3)(4) A 204 A (3)

A 352 LC1 A 204 B (3)1.7 C-1/2 Mo A 204 C (3)

1/2Cr-1/2Mo A 182 F2

Ni-Cr-1/2 Mo A 217 WC4 (4)

Ni-Cr-1Mo A 217 WC5 (4) 1.9 1 Cr-1/2 Mo A 182 F12 (4)

11/4Cr-1/2Mo A 182 F11 (4) A 217 WC6 (4) A 387 11Cl.2 1.10 21/4Cr-1Mo A 182 F22 A 217 WC9 (4) A 387 22Cl.2 1.13 5Cr-1/2 Mo A 182 F5 A 217 C5 (4)

A 182 F5a 1.14 9Cr-1Mo A 182 F9 A 217 C12 (4) 2.1 18Cr-8Ni A 182 F304 (5) A 351 CF3 A 240 304 (5)(6)

A 182 F304H A 351 CF8 (5) A 240 304H 2.2 16Cr-12Ni-2Mo A 182 F316 (5) A 240 316 (5)(6)

A 182 F316H A 240 316H

18Cr-13Ni-3Mo A 240 317 (5)(6)

18Cr-9Ni-2Mo A 351 CF3M A 351 CF8M (5)

Source: ASME/ANSI B16.5 - 1988. With permission from the American Society of Mechanical Engineers.

FIGURE 20




The Materials Specification Table

The Materials Specification Table is divided into two sections:

Material groups.

Product forms.

Material Groups

Material specifications are grouped within specific Material Group Numbers in this table.These groupings have been made to provide compatible flanged-joint ratings for materialsthat are likely to be used together. The lowest strength material in each group was used todetermine the pressure rating for that group at a given temperature. Therefore, the ratings ofsome materials within a group are conservative.

Product Forms

This table also indicates three different product forms that are possible for flanges and flangedfittings: forgings, castings, and plates. The relevant ASTM specifications are specified forthese product forms. Most material groups have representative specifications in each of theproduct forms. However, some material chemistries within a material group might not berepresented in each product form. For example, carbon steel in Group 1.1 can be found in allthree product forms. However, C-Mn-Si steel in Group 1.1 can be plate only. ASME/ANSIB16.5 specifies that plate may be used only for blind flanges, and certain sized reducingflanges where a blind flange is used.

Saudi Aramco Practice

Refer to Work Aid 1 for a procedure to select the appropriate material specification andMaterial Group Number. Saudi Aramco typically will use ASTM A 350, Grade LF2 forgedcarbon steel flanges for most process plant applications. Referring to Figure 20, A350, GradeLF2 is in Material Group No. 1.1.




Determining Flange and Fitting Rating Class

Flanges and Flanged Fittings

After the Material Group has been determined, the next step in the selection process forflanges and flanged fittings is to select the appropriate class. The class is based on pressureand temperature, and is determined by using pressure/temperature rating tables, the MaterialGroup, design metal temperature, and design pressure. Selecting the class sets all the detaileddimensions for flanges and flanged fittings. The objective is to select the lowest class that isappropriate for the design conditions.

This section will discuss the appropriate pressure/temperature rating classes for flanges andflanged fittings.

The following will deal only with ASME/ANSI B16.5 because this is the most widely usedand broadest flange standard. The classes of API 605, MSS-SP-44, and ASME/ANSIB16.47 flanges are identical to those that are contained in ASME/ANSI B16.5 for the samenumber designations. API 605 is limited to carbon steel material.

Pressure/Temperature Rating Tables

The class accounts for the required flange design temperature and pressure.

ASME/ANSI B16.5 contains seven classes designated Classes 150, 300, 400, 600, 900,1500, and 2500.

Each class specifies the design pressure and temperature combinations that areacceptable for a flange having that designation.

As the number of the class increases, the strength of the flanges increases. Therefore,higher flange classes can withstand higher pressure/temperature combinations.

As the number of the class increases, the cost of the flanges also increases because morematerial is being used to make the higher class stronger. Therefore, there is aneconomic incentive to use the lowest class that will meet the design requirements.

Each of the seven classes has a table in ASME/ANSI B16.5 that provides the ratings forthat class. Figure 21 is a reproduction of Table 2 for ANSI Class 150. Note that all theMaterial Group Numbers are represented in this table.

ASME/ANSI B31.3 and B31.4 permit higher pressures than are indicated in the ratingtable for conditions that exist for shorter duration. These will be discussed in a latersection.

A general flange class selection procedure is contained in Work Aids 2 and 3.




Figure 22 is a partial copy of Table 9 from ASME/ANSI B16.5 which provides dimensionsfor Class 150 flanges. The flange geometry is completely specified by the dimensions givenin this table. As previously mentioned, the flange dimensions for a given class are the samefor all possible flange materials. Therefore, variations in material strength are accommodatedby changes in acceptable temperature/pressure combinations within a given class, rather thanchanging flange dimensions. A similar table is contained in ASME/ANSI B16.5 for eachclass, but the flange dimensions differ in each class. For the same pipe sizes, flanges becomethicker, heavier, and stronger as the class increases.

Specifying the flange size, material, and class completes most of what is necessary for theselection of a ASME/ANSI B16.5 flange. The flange type, facing, bolting material, andgasket type and material must be added to complete the flange selection process.




ANSI CLASS 150 PRESSURE/TEMPERATURE RATINGS


FIGURE 21




ANSI CLASS 150 PRESSURE/TEMPERATURE RATINGS, CONT'D


FIGURE 21, CONT'D




DIMENSIONS OF CLASS 150 FLANGES


FIGURE 22




Selecting Pressure/Temperature Ratings for Butt-Welded, Socket-Welded andThreaded Fittings

The terms class or rating are not associated with steel butt-welded fittings. Steel butt-weldedfittings have pressure/temperature limitations that are identical to that of piping of the samematerial, diameter, and wall thickness. Thus, their thicknesses typically are selected to beidentical to that of the pipe they are welded to.

Forged steel socket-welded and threaded fittings have ratings, but these ratings differ fromthose of flanges and flanged fittings.

ANSI B16.11, Forged Steel Fittings, Socket-Welding and Threaded, contains a basis forpressure/temperature ratings for these piping components.

Threaded fittings are designated as Pressure Class 2000, 3000 and 6000.

Socket-welded fittings are designated as Pressure Class 3000, 6000, or 9000.

Design temperature and other service conditions might limit the use of a particularfitting material, based on requirements that are contained in the applicable piping code.Within these limits, the maximum allowable pressure of a fitting is based on thatcomputed for straight, seamless pipe of equivalent material. This calculation wasdiscussed in MEX 101.03. The wall thickness that is used for the computation is thenominal wall thickness for the given pipe size, reduced by the appropriatemanufacturing tolerance, corrosion allowance, and threading allowance (if applicable).

The following table summarizes the pipe schedule that corresponds to each fitting pressureclass for rating purposes:

PressureClass of Fitting

Type ofFitting

Pipe Used forSchedule No.

Rating BasisWall Designation

2000 Threaded 80 XS3000 Threaded 160 ---6000 Threaded --- XXS

3000 Socket-Welded 80 XS6000 Socket-Welded 160 ---9000 Socket-Welded --- XXS

Saudi Aramco Engineering Standard, SAES-L-007, Selection of Metallic Pipe Fittings,further specifies that for steel piping in hazardous services, threaded and socket-weldedfittings shall be at least Pressure Class 3000.




Determining the Flange and Fitting Maximum Allowable Operating Pressure(MAOP)

An engineer may be asked to check the maximum allowable operating pressure (MAOP) for aflange or fitting when there are changes in the piping design conditions, such as an increase inpressure. This section discusses how to determine the MAOP of the flange/fitting for a giventemperature, given a flange/fitting class.

Previous discussions showed how the required class is determined for flanges and flangedfittings, and threaded and socket-welded fittings. They also described how thepressure/temperature limitations of wrought steel butt-welded fittings are determined. In eachcase, it is a relatively simple matter to work backwards to determine the MAOP for aparticular flange or fitting.

Work Aid 3 provides a procedure for determining MAOP.

Conditions Beyond Normal Design Conditions

Previous sections described how to determine the maximum allowable long-term operatingpressure for flanges and fittings. The ASME/ANSI B31 Codes permit an allowance foroccasional excursions above this long-term design pressure. However, the codes differregarding the permissible extent of these excursions.

In ASME/ANSI B31.3 piping systems, it is permissible to exceed the pressure rating or theallowable stress for pressure design at the temperature of the increased condition by not morethan:

33% for no more than 10 hours at any one time and no more than 100 hours/year, or

20% for no more than 50 hours at any one time and no more than 500 hours per year.

Referring to the Class 300 flange in Sample Problem 2 at 371C (700F), the pressure couldrise to 758 psig (1.33 x 570) or 684 psig (1.2 x 570) during a short-time excursion, dependingon the duration of the excursion.

The ASME/ANSI B31.4 and ASME/ANSI B31.8 transportation piping codes differ fromB31.3 and from each other with regard to conditions beyond normal design conditions.ASME/ANSI B31.4 will permit a 10% increase over the rated pressure for variations fromnormal operation, such as those caused by liquid surges. It does not contain any detailscovering the maximum duration or number of these variations. ASME/ANSI B31.8 does notcontain any permissible allowance for pressure increases above the normal maximum ratedpressure.




WORK AID 1: Procedures for Determining the Material Group for ASME/ANSIFlanges and Flanged Fittings


The following procedure may be used to select the correct flange material and Material GroupNumber.

1. Identify the material chemistry (such as carbon steel, 1 1/4 Cr - 1/2 Mo) that is beingused for the connected piping.

2. Identify the design temperature.

3. For pipeline applications, identify the Specified Minimum Yield Stress of the pipematerial that is being used.

4. If the piping material is not carbon steel, refer to Table 1A in ASME/ANSI B16.5(excerpted in Figure 23), and continue in this step. If it is carbon steel, go to Step 5.

a. Select the appropriate material specification that corresponds to the identifiedmaterial chemistry and product form. The product form for flanges will almostalways be a forging.

b. Identify the Material Group Number that corresponds to the material specification.




5. If the material is carbon steel (or a low-alloy specification that is identified in SAES-L-009 and 02-SAMSS-011), refer to SAES-L-009 and Table 1 of 02-SAMSS-011 to selectthe appropriate flange material specification. The most common carbon steel flangematerial specifications for plant piping systems are summarized below. Refer to SAES-L-009 and 02-SAMSS-011 for conditions that are not included, and for pipelineapplications.

Flare Material Limitations

ASTM A 105 Restricted to nonhydrocarbon service (except flarelines), -18 to 425C(0 to 800F)

ASTM A 350 Gr. LF 2 -30 to 345C (-20 to 650F).

ASTM A 350 Gr. LF 2 LO TEMP -45 to 345C (-50 to 650F). Impact testing required.

Identify the Material Group Number that corresponds to the material specification, fromTable 1A in ASME/ANSI B16.5 (excerpted in Figure 23). Material Group 1.1corresponds to the above specifications.

6. Refer to SAES-L-009 and 02-SAMSS-011 for additional requirements.

Threaded, Socket-Welded, or Butt-Welded Fittings

Material selection for threaded, socket-welded, or butt-welded fittings is straightforward. Thematerial for forged, wrought, or cast fittings is selected to have a chemistry that is comparableto that of the pipe material it is connected to. Appropriate ASTM material specifications areavailable to meet these requirements.




ASME/ANSI B16.5, TABLE 1A - LIST OF MATERIAL SPECIFICATIONS(EXCERPT)

Material Groups Product FormsMaterial Nominal Forgings Castings Plates

Group No. Designation Steel




1.1 Carbon A 105 (1)(2) A 216 WCB (1) A 515 70 (1)A 350 LF2 A 516 70 (1)

C-Mn-Si A 537 Cl.1 1.2 Carbon A 216 WCC (1)

A 352 LCC

2 1/2 Ni A 352 LC2 A 203 B

3 1/2 Ni A 350 LF3 A 352 LC3 A 203 E 1.3 Carbon A 352 LCB (1) A 515 65 (1)

A 516 65 (1)

2 1/2 Ni A 203 A

3 1/2 Ni A 203 D 1.4 Carbon A 350 LF1 A 515 60 (1)

A 516 60 1.5 C-1/2 Mo A 182 F1 (3) A 217 WC1 (3)(4) A 204 A (3)

A 352 LC1 A 204 B (3)1.7 C-1/2 Mo A 204 C (3)

1/2Cr-1/2Mo A 182 F2

Ni-Cr-1/2 Mo A 217 WC4 (4)

Ni-Cr-1Mo A 217 WC5 (4) 1.9 1 Cr-1/2 Mo A 182 F12 (4)

11/4Cr-1/2Mo

A 182 F11 (4) A 217 WC6 (4) A 387 11Cl.2

1.10 21/4Cr-1Mo A 182 F22 A 217 WC9 (4) A 387 22Cl.2 1.13 5Cr-1/2 Mo A 182 F5 A 217 C5 (4)

A 182 F5a 1.14 9Cr-1Mo A 182 F9 A 217 C12 (4) 2.1 18Cr-8Ni A 182 F304 (5) A 351 CF3 A 240 304 (5)(6)

A 182 F304H A 351 CF8 (5) A 240 304H 2.2 16Cr-12Ni-2Mo A 182 F316 (5) A 240 316 (5)(6)

A 182 F316H A 240 316H

18Cr-13Ni-3Mo A 240 317 (5)(6)

18Cr-9Ni-2Mo A 351 CF3M A 351 CF8M (5)


FIGURE 23




WORK AID 2: Guidelines for Determining the Flange and Fitting Rating Class

Refer to Table 2 of ASME/ANSI B16.5. Excerpts from this table are contained inFigure 24 for Classes 150, 300, and 600 for the most commonly used Material Groups.

Material Group Number is read across the top of the table.

Flange design temperature is read down the left side of the table.

The numbers in the table are the maximum allowable flange design pressures for aparticular combination of flange Material Group Number and design temperature.Linear interpolation may be used for design temperatures located between the valueslisted.

The objective is to ensure that the specified pipe design pressure is no greater than themaximum acceptable pressure of a given class at the specified design temperature.Proceed to a progressively higher class until the correct one is found for the designconditions.

Read down the columns for a particular material. The allowable design pressuredecreases with increasing design temperature. The dimensions of ASME/ANSI B16.5flanges are fixed for a given class and pipe size. Therefore this decrease in allowablepressure with increasing temperature ensures that the standard flange design will not faildue to the reduction in material strength at higher temperature. Material/designtemperature combinations that do not have a pressure indicated are not acceptable.




ASME/ANSI B16.5, TABLE 2 - PRESSURE/TEMPERATURE RATINGS FOR CLASS150

MaterialGroup

No.1.1 1.2 1.3 1.4 1.5 1.7 1.9 1.10 1.13 1.14 2.1 2.2 2.3 2.4 2.5 2.6 2.7

Alloy Steels Austenitic Steels

Temp.,F Carbon Steel

C-1/2Mo

1/2Cr-1/2Mo,Ni-Cr-Mo

1Cr-1/2Mo,1 1/4Cr-1/2Mo

2 1/4Cr-

1Mo

5Cr-1/2Mo

9Cr-1Mo

Type

304

Type

316

Type

304L

_ _ _

Type

316L

Type

321

Types347,348

Type

309

Type310

-20 to 100 285 290 265 235 265 290 290 290 290 290 275 275 230 275 275 260 260200 260 260 250 215 260 260 260 260 260 260 235 240 195 235 245 230 230300 230 230 230 210 230 230 230 230 230 230 205 215 175 210 225 220 220400 200 200 200 200 200 200 200 200 200 200 180 195 160 190 200 200 200

500 170 170 170 170 170 170 170 170 170 170 170 170 145 170 170 170 170600 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140650 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125700 110 110 110 110 110 110 110 110 110 110 110 110 110 110 110 110 110

750 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95800 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80850 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65900 50 50 50 50 50 50 50 50 50 50 50 50 ... 50 50 50 50

950 35 35 35 35 35 35 35 35 35 35 35 35 ... 35 35 35 351000 20 20 20 20 20 20 20 20 20 20 20 20 ... 20 20 20 20


FIGURE 24




ASME/ANSI B16-5, TABLE 2 - PRESSURE/TEMPERATURE RATINGS FOR CLASS300

MaterialGroup

No.1.1 1.2 1.3 1.4 1.5 1.7 1.9 1.10 1.13 1.14 2.1 2.2 2.3 2.4 2.5 2.6 2.7



C-1/2Mo


1Cr-1/2Mo,1 1/4Cr-1/2Mo

2 1/4Cr-

1Mo

5Cr-1/2Mo

9Cr-1Mo

Type

304

Type

316

Type

304L

_ _ _

Type

316L

Type

321

Types347,348

Type

309

Type

310

-20 to 100 740 750 695 620 695 750 750 750 750 750 720 720 600 720 720 670 670200 675 750 655 560 680 750 710 715 750 750 600 620 505 610 635 605 605300 655 730 640 550 655 730 675 675 730 730 530 560 455 545 590 570 570400 635 705 620 530 640 705 660 650 705 705 470 515 415 495 555 535 535

500 600 665 585 500 620 665 640 640 665 665 435 480 380 460 520 505 505600 550 605 535 455 605 605 605 605 605 605 415 450 360 435 490 480 480650 535 590 525 450 590 590 590 590 590 590 410 445 350 430 480 465 465700 535 570 520 450 570 570 570 570 570 570 405 430 345 420 470 455 455

750 505 505 475 445 530 530 530 530 530 530 400 425 335 415 460 445 445800 410 410 390 370 510 510 510 510 500 510 395 415 330 415 455 435 435850 270 270 270 270 485 485 485 485 440 485 390 405 320 410 445 425 425900 170 170 170 170 450 450 450 450 355 450 385 395 ... 405 430 415 415

950 105 105 105 105 280 345 380 380 260 370 375 385 ... 385 385 385 3851000 50 50 50 50 165 215 225 270 190 290 325 365 ... 355 365 335 3501050 ... ... ... ... ... 190 140 200 140 190 310 360 ... 345 360 290 3351100 ... ... ... ... ... ... 95 115 105 115 260 325 ... 300 325 225 290

1150 ... ... ... ... ... ... 50 105 70 75 195 275 ... 235 275 170 2451200 ... ... ... ... ... ... 35 55 45 50 155 205 ... 180 170 130 2051250 ... ... ... ... ... ... ... ... ... ... 110 180 ... 140 125 100 1601300 ... ... ... ... ... ... ... ... ... ... 85 140 ... 105 95 80 120

1350 ... ... ... ... ... ... ... ... ... ... 60 105 ... 80 70 60 801400 ... ... ... ... ... ... ... ... ... ... 50 75 ... 60 50 45 551450 ... ... ... ... ... ... ... ... ... ... 35 60 ... 50 40 30 401500 ... ... ... ... ... ... ... ... ... ... 25 40 ... 40 35 25 25

Source: ASME/ANSI B16.5 -1988. With permission from the American Society of Mechanical Engineers.

FIGURE 24, CONT'D




ASME/ANSI B16-5, TABLE 2 - PRESSURE/TEMPERATURE RATINGS FOR CLASS600

MaterialGroup

No.1.1 1.2 1.3 1.4 1.5 1.7 1.9 1.10 1.13 1.14 2.1 2.2 2.3 2.4 2.5 2.6 2.7



C-1/2Mo


1Cr-1/2Mo,1 1/4Cr-1/2Mo

2 1/4Cr-

1Mo

5Cr-1/2Mo

9Cr-1Mo

Type

304

Type

316

Type

304L

_ _ _

Type

316L

Type

321

Types347,348

Type

309

Type

310

-20 to 100 1480 1500

1390

1235

1390

1500

1500

1500

1500

1500

1440

1440

1200

1440

1440 1345

1345

200 1350 1500

1315

1125

1360

1500

1425

1430

1500

1500

1200

1240

1015

1220

1270 1210

1210

300 1315 1455

1275

1095

1305

1455

1345

1355

1455

1455

1055

1120

910 1090

1175 1140

1140

400 1270 1410

1235

1060

1280

1410

1315

1295

1410

1410

940 1030

825 990 1110 1065

1065

500 1200 1330

1165

995 1245

1330

1285

1280

1330

1330

875 955 765 915 1035 1010

1010

600 1095 1210

1065

915 1210

1210

1210

1210

1210

1210

830 905 720 875 985 955 955

650 1075 1175

1045

895 1175

1175

1175

1175

1175

1175

815 890 700 855 960 930 930

700 1065 1135

1035

895 1135

1135

1135

1135

1135

1135

805 865 685 840 935 910 910

750 1010 1010

945 885 1065

1065

1065

1065

1065

1065

795 845 670 830 920 895 895

800 825 825 780 740 1015

1015

1015

1015

995 1015

790 830 660 825 910 870 870

850 535 535 535 535 975 975 975 975 880 975 780 810 645 815 890 850 850900 345 345 345 345 900 900 900 900 705 900 770 790 ... 810 865 830 830

950 205 205 205 205 560 685 755 755 520 740 750 775 ... 775 775 775 7751000 105 105 105 105 330 425 445 535 385 585 645 725 ... 715 725 670 7001050 ... ... ... ... ... 380 275 400 280 380 620 720 ... 695 720 585 6651100 ... ... ... ... ... ... 190 225 205 225 515 645 ... 605 645 445 585

1150 ... ... ... ... ... ... 105 205 140 150 390 550 ... 475 550 345 4951200 ... ... ... ... ... ... 70 110 90 105 310 410 ... 365 345 260 4101250 ... ... ... ... ... ... ... ... ... ... 220 365 ... 280 245 200 3251300 ... ... ... ... ... ... ... ... ... ... 165 275 ... 210 185 160 240

1350 ... ... ... ... ... ... ... ... ... ... 125 205 ... 165 135 115 1601400 ... ... ... ... ... ... ... ... ... ... 90 150 ... 125 105 90 1101450 ... ... ... ... ... ... ... ... ... ... 70 115 ... 95 80 60 751500 ... ... ... ... ... ... ... ... ... ... 50 85 ... 75 70 50 55


FIGURE 24, CONT'D




Use the following procedure to determine the Class for ASME/ANSI B16.5 flanges andflanged fittings. Fill in the blank lines as required.

Given Generic pipe material ____________________________

(such as Carbon Steel, C-1/2 M, 3-1/2 Ni) Design Pressure, kPa (psig) ____________________________ Design Temperature, C (F) ____________________________ Nominal Pipe Size, mm (in.) ____________________________ Pipe material SMYS (pipeline applications),

MPa (psi) ____________________________

Selection Procedure1. Review SAES-L-009 and 02-SAMSS-011 for carbon and low alloy steel flange

requirements.Saudi Aramco Requirement ____________________________

2. Determine the required flange product form (forging, casting, plate). Most pipe flangesare forgings.Product Form ____________________________

3 Proceed to Table 1A of ASME/ANSI B16.5 to select Material Group No., consideringthe required material and product form. Flange material is to have comparablechemistry to pipe material (except possibly lapped flanges), and meet SAES-L-009 and02-SAMSS-011 requirements.Material Group Number ____________________________

4. Proceed to Table 2 of ASME/ANSI B16.5 to determine flange class. For the specifieddesign temperature, determine the maximum allowable operating pressure (MAOP) forthe Material Group No., proceeding from lower to higher classes.

Class 150 300 400 600 900 1500 2000MAOP

Complete this table only until the MAOP for a class exceeds the design pressure. Therequired flange class is the lowest one whose MAOP exceeds the design pressure.

Note that SAES-L-009 prohibits the use of Class 400 carbon steel flanges for nominal sizesless than 750 mm (30 in.).

Required Class ____________________________




WORK AID 3: Procedures for Determining the Flange and Fitting MaximumAllowable Operating Pressure (MAOP)

The following procedure may be used to determine the MAOP for flanges and fittings.


1. Identify the flange Material Group Number, class, and design temperature.

2. From the appropriate class from Table 2 of ASME/ANSI B16.5, read the MAOP fromthe intersection of the Material Group Number and design temperature. Use linearinterpolation for intermediate values of design temperature.

Butt-Welded Fittings

1. Identify the fitting material, nominal diameter, nominal wall thickness, and designtemperature.

2. Subtract the appropriate manufacturing tolerance and specified corrosion allowancefrom the specified nominal thickness.

3. Calculate the MAOP in the same manner as for straight section of seamless pipe, asdiscussed in MEX 101.03.

Threaded and Socket-Welded Fittings

1. Identify the fitting material, nominal size, class, design temperature, and whether it isthreaded or socket-welded.

2. Select the appropriate nominal wall thickness for the equivalent seamless pipe from thefollowing table:

Fitting Class Fitting Type Pipe Thicknessfor

Rating Basis

Schedule Number Wall Designation2000 Threaded 80 XS3000 Threaded 160 6000 Threaded XXS3000 Socket-welded 80 XS6000 Socket-welded 160 9000 Socket-welded XXS




3. Determine the nominal pipe thickness for seamless pipe based on the pipe size andthickness basis determined in Step 3. See MEX 101.03 for standard pipe thicknessesbased on the Schedule Number or Wall Designation.

4. Subtract the appropriate manufacturing tolerance, specified corrosion allowance, andthreading allowance (if applicable) from the nominal thickness determined in Step 3.

5. Calculate the MAOP, assuming seamless pipe, using the procedure that was discussed inMEX 101.03.




GLOSSARY

ANSI American National Standards Institute.

ASME/ANSI B16.5 Pipe Flanges and Flanged Fittings. Provides dimensional detailsand pressure/temperature ratings for steel flanges in standard pipesizes of 13 through 600 mm (1/2 through 24 in.).

ANSI B16.9 Factory-Made Wrought Steel Butt-Welding Fittings. Providesrequirements for carbon and alloy steel butt-welding fittings in pipesizes 13 through 1,200 mm (1/2 through 48 in.).

ANSI B16.11 Forged Steel Fittings, Socket-Welding and Threaded. Providesrequirements for forged steel socket-welded and threaded fittings insizes 3 through 100 mm (1/8 through 4 in.).

ASME American Society of Mechanical Engineers.

ASTM American Society for Testing and Materials.

AWWA American Water Works Association.

CR Neoprene rubber.

Class A numerical designation given to a flange or flanged component thatis used to indicate its allowable pressure/temperature rating. Thesedesignations are Class 150, 300, 400, 600, 900, 1500, and 2500, inaccordance with ASME/ANSI B16.5.

gasket A resilient material inserted between flanges and seated against theirfaces to provide a seal.

MSS Manufacturers Standardization Society of the Valve and FittingsIndustry.

MSS-SP44 Steel Pipe Line Flanges. Provides flange dimensions for use in highpressure pipeline services in standard pipe sizes 300-1,500 mm (12-60 in.).

NBR Nitrile Buna-N rubber.




NPS Nominal pipe size. For pipe sizes 350 mm (14 in.) and above, thenominal pipe size equals the outside pipe diameter.

SBR Styrene-butadiene rubber.

socket-weld A pipe attachment detail in which a pipe is inserted into a recessedarea of a fitting, and then fillet welded between its outside diameterand the fitting end.

spiral-wound gasket A gasket type formed by alternately winding strips of metal and softfiller material around a mandrel.

flanges and fittings types and classes

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