ASME B16.5

Flanges Contents [hide]

1 Flange Descriptions 2 Flange Specification 3 Flange Materials 4 Flange Size 5 Flange Facing Types 6 Flange Facing Code, ASME 7 Flange Facing Finish 8 Flange Specification and Identification 9 Flange ANSI B16.5 and B16.47 Class Rating 10 Flange Pressure Classes 11 Flange Maximum Pressure and Temperature Ratings, ANSI B16.5 (in) 12 Flange Dimensional Tolerances, ASME B16.5 (in) 13 Flange Welding Bevel Standard, ANSI B16.5 and B16.47 (in)

Flange Descriptions Blind Flange - These flanges do not have a bore. It is used to blind off a flange or even a valve. When used at the end of a pipe or fitting, it provides an easy to open access for further extension of the pipe. The blind flange and its bolts are stressed more than any other flange. Lap Joint Flange - This flange is used with a lap joint stub end fitting. It is similar to a slip-on flange, but with two differences. The radius and the flat face, both allow the flange to secure against the stub end fitting. This is useful where alignment of bolt holes is difficult, such as with spools to be attached to flanged nozzles of vessels. A lap joint is used in low pressure applications and not suitable where high external of heavy loads are present. Slip-on Flange - Slip-on flanges are designed to slip over the outside of pipe, long-tangent elbows, reducers, and swages. The flange has poor resistance to shock and vibration. It is easier

to align than welding neck flange. This flange is ideal for low pressure applications since the strength when under internal pressure is about one third that of a weld neck flange. Socket Flange - This is similar to a slip-on flange, except they have a bored and counter bore. The counter bore allows the pipe to fit into the socket/counter bore. The bore of the flange is the same diameter as the inside of the pipe. These flanges were first designed for small diameter, high pressure pipe. Threaded Flange - It is similar to a slip-on Flange, but has internal threads. It is normally used for low pressure and not used where temperature or stress is very high. Weld Neck Flange - This flange comes in two types, regular and long. The hub of the weld neck is designed to reduce the stress at the base of the flange. Regular weld neck flanges are used with buttweld fittings and long weld neck flanges are usually used with equipment and vessel nozzles. A long weld neck flange is rarely used with pipe. Both types of flanges are bored to match the inside diameter of the pipe or fitting to which it will be welded to. They are suitable where high pressure, extreme temperatures, shear impact and vibratory stresses apply. Ring Joint Facing Flange - Also known as RTJ Flanges. These are used for a leak-proof connection in high pressure applications. The flange has a hexagonal groove sealing surface and is fitted with a ring that is compressed in a groove.

Flange Specification ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard ASME B16.47 - Large Diameter Steel Flanges: NPS 26 Through NPS 60 Metric/Inch Standard (Covers MSS SP-44 and API 605 flanges) MSS SP-44 - Steel Pipeline Flanges (Covered by ASME B16.47 Series A) API 605 - Cancelled (Covered by ASME B16.47 Series API Spec 6A - Specification for Wellhead and Christmas Tree Equipment

ASME B16.5 and ASME B16.47 cover pipe flanges up to NPS 60 (B16.5 from 1/2" to 24" and B16.47 from 26" to 60"). ANSI B16.47 covers two series of flanges, Series A is equal to MSS SP44-44, and Series B is equal to API 605 (API 605 has been canclled).

Flange Materials Standards usually specify the material from which the flange is produced.

Flange Size There are available flange sizes and grades for all standard pipe wall thicknesses and pressure ratings.

Flange Facing Types

One end of the flex joint is a flat face to match the pump face and the other end is raised face to match the flange.

Flat Face (FF) - Typically these flanges are used on pump facings or on fiberglass flanges where the torque of compressing the gasket will damage the flange body. They are found in 150# and 300# ratings. Their principal use is to make connections with 125# and 250# cast iron flanges, respectively. Raised Face (RF) - The raised face is the most common used flange face. It is called raised face because the gasket is raised 1/16" and 1/4" above the bolt circle face: 1/16" for 300 lb. and less, 1/4" for 400 lb. and more. The flange facings are machine finished to ANSI/ASME B16.5 requirements. Ring Type Joint (RTJ) (Class 300 and larger) - This flange is normally used for high pressure gas pipe work. Ring type gaskets must be used on this type of flange. Tongue and Groove (T&G) Small Tongue and Groove Large Tongue and Groove Small Male and Female

Large Male and Female

Flange Facing Code, ASME ASME B16.5 requires that for flanges and flanged fittings the surface is to have a specific roughness. A concentric or spiral serrated finish with 30 to 55 groves per inch and a surface roughness between 125 and 500 microinches. This allows different surface grades to be used with various types of gaskets to ensure a tight flange surface. These are some of the common finishes used on raised faces and flat faces.

Flange Facing Finish The flange face finish is determined by the standard used and measured as an Arithmetical Average Roughness Height (AARH). An example would be ANSI B16.5 which specifies face finishes within a range 125AARH - 500AARH (3.2 Ra to 12.5 Ra). Cold Water - It has a mirror like finish. This is made with a wide tool at a high speed which gives a finished surface much like a ground surface. When a surface has this type of finish it is normally used metal to metal, not with a gasket. It is seldom used in the oil, chemical or related industries. Concentric Serrated - A 90 degree inclined angle tool is used to make the grove. It makes a grove 1/64" deep and 1/32" apart in a concentric circle. Smooth - This can be made with several different types of tool shapes. No tool markings will appear to the naked eye on the surface. The roughness of the finish is from 125-250 microinch. Spiral Serrated - This is similar to a stock finish but the difference between them is the way the grove is made. A 90 degree inclined angle tool is used to make the grove. It makes a grove 1/64" deep and the feed is 1/32". Stock - The surface is created by a continuous spiral groove. The roughness of the finish is from 125 to 500 microinches and is cut with a tool with an approximately 0.06 inches or larger radius.

Flange Specification and Identification All flanges should be stamped for identification on the outside diameter of the base for east identification with:

Flange Stamping

Manufacturer's name. Nominal pipe size (NPS). Pressure rating (150 lb., 300 lb., etc.) Face designation - the machined gasket surface. Bore - the nominal pipe size (NPS). Material designation Ring gasket number - used for ring joint flange. Heat number of code - the batch number used when forged and tested Normally, a flange should be hard stamped but in some cases the stamping may not be legible or completely visible for observation. In that case it may have to be visually observed and physically measured. Check the number of bolts and bolt size, measure the flange and pipe size. Then compare these measurements with flange data.

Flange ANSI B16.5 and B16.47 Class Rating

Flange Type

ANSI

ASME

ANSI

B16.47

B16.47

B16.5

Series A

Series B

1/2"-24"

(MSS SP-44)

(API 605)

26"-60"

26"-60"

Blind

150-2500

300-900

300-900

Lap Joint

150-2500

-

-

Slip-On

150-2500

-

-

Socket

150-2500

-

-

Threaded

150-2500

-

-

Weld Neck

150-2500

150-900

75-900

Flat/Raised Facing

As Above

As Above

As Above

Ring Joint Facing

150-2500

300-900

300-900

Other Facings

150-2500

-

-

Flange Pressure Classes Flanges are normally manufactured in seven basic ratings: 150 Lb, 300 Lb, 400 Lb, 600 Lb, 900 Lb, 1500 Lb and 2500 Lb. The ratings can be expressed in different ways but mean the same thing - 150 Lb, 150 Lbs, 150# or Class 150. Each class of flange can handle more pressure than the previous class because of its construction. The higher the class is, the thicker the metal is. Thus a higher pressure can be handled. There a numerous factors that can affect the pressure capability of a flange, such as the type of metal that is used. But basically when pressure goes down, the temperature goes up and vise versa.

Flange Maximum Pressure and Temperature Ratings, ANSI B16.5 (in) This table is in accordance with ANSI B16.5 maximum allowable non-shock pressure (psig) and temperature ratings for steel pipe flanges and flanged fittings. Based on American Society of Mechanical Engineers - ASME B16.5 ANSI Class

150

Temperature oF

300

400

600

900

1500

2500

Maximum Allowable Non-Shock Pressure PSIG

-20 to 100

285

740

990

1480

2220

3705

6170

200

260

675

900

1350

2025

3375

5625

300

230

655

875

1315

1970

3280

5470

400

200

635

845

1270

1900

3170

5280

500

170

600

800

1200

1795

2995

4990

600

140

550

730

1095

1640

2735

4560

650

125

535

715

1075

1610

2685

4475

700

110

535

710

1065

1600

2665

4440

750

95

505

670

1010

1510

2520

4200

800

80

410

550

825

1235

2060

3430

850

65

270

355

535

805

1340

2230

900

50

170

230

345

515

860

1430

950

35

105

140

205

310

515

860

1000

20

50

70

105

155

260

430

Flange Dimensional Tolerances, ASME B16.5 (in)

Weld Neck Flange

Dimension

Flange

A

Outside Diameter

Tolerance

When O.D. is 24" or less: ±1/16" (1.6mm) When O.D. is over 24": ±1/8" (3.2mm) 10" and smaller: ±1/32" (0.8mm)

D

Inside Diameter

12" thru 18": +1/8" (3.2mm) 20" and larger: -1/16" (1.6mm) 1/16" raised face: ±1/32" (0.8mm)

B

Diameter of contact face

1/4" Raised Face, Tongue & Groove (male & female): ±1/64" (0.4mm) When hub base is 24" or smaller: ±1/16"

J

Diameter of hub at base

(1.6mm) When hub base is over 24": ±1/8" (3.2mm)

H

Diameter of hub at point of welding

5" and smaller: +3/32" (2.4mm), -1/32" (0.8mm) 6" and larger: +5/32" (4.0mm), -1/32 (0.8mm)

P

Drilling

Bolt circle: ±1/16" (1.6mm) Bolt hole spacing: ±1/32" (0.8mm)

Eccentricity of bolt circle with respect to facing

C

Thickness

2 1/2" and smaller ±1/32" (0.8mm) max. 3" and larger ±1/16" (1.6mm) max. 18" and smaller: ±1/8" (3.2mm), -0" 20" and larger: ±3/16" (4.8mm), -0"

K

Length of hub

10" and smaller: ±1/16" (1.6mm) 12" and larger: ±1/8" (3.2mm)

Blind Flange, Lap Joint Flange, Slip-on Flange,Socket Flange, Threaded Flange

Dimension

Flange

A

Outside Diameter

Tolerance

When O.D. is 24" or less: ±1/16" (1.6mm) When O.D. is over 24": ±1/8" (3.2mm) Threaded: within limits of boring gauge

D

Inside Diameter

Lap Joint, Slip-on, Socket 10" and smaller: ±1/32" (0.8mm), 0" 12" and larger: -1/16" (1.6mm), 0"

B

Diameter of contact face

1/16" raised face: ±1/32" (0.8mm) 1/4" Raised Face, Tongue & Groove (male & female): ±1/64" (0.4mm) Threaded (S): within limits of boring gauge

E, F, S

Diameter of bore

Lap Joint (F), Slip-on (E), Socket (E) 10" and smaller: ±1/32" (0.8mm), 0" 12" and larger: -1/16" (1.6mm), 0"

Bolt circle: ±1/16" (1.6mm) Bolt hole spacing: ±1/32" (0.8mm) P

Drilling

Eccentricity of bolt circle with respect to facing 2 1/2" and smaller ±1/32" (0.8mm) max. 3" and larger ±1/16" (1.6mm) max.

C

Thickness

18" and smaller: ±1/8" (3.2mm), -0" 20" and larger: ±3/16" (4.8mm), -0"

L, M

Length of hub

18" and smaller: ±1/8" (3.2mm), ±1/32" (0.8mm) 20" and larger: ±3/16" (4.8mm), ±1/16" (1.6mm)

Flange Welding Bevel Standard, ANSI B16.5 and B16.47 (in) J = Diameter of hub at base H = Outside Diameter of flange and mating pipe D = Inside Diameter of flange t = Wall thickness of flange hub at bevel

For bevel wall thickness (t) from 0.19 in. (3/16") to 0.88 in. (7/8") inclusive.

For bevel wall thickness (t) greater than 0.88 in (7/8").

Data shown on this page was either gathered and verified using data available in the public domain or has been calculated by the staff at Piping-Designer.com. It is up to the end user to verify data prior to use for any project. This page may not be reproduced without the explicit written permission of PipingDesigner.com. © 2006-2012 Piping Designer, LLC