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Check the common difference between Class 150 forged fittings & 150# pipe flanges


Class 150 Fittings Vs Class 150LB Flange



Difference between Class 150 forged fittings & flanges

Difference between Class 150 forged fittings & flanges


Check the process considerations of 150# socket weld fittings and also remember to compare working pressure capacity with class 150 flange


Three considerations for Class 150 stainless steel fittings

  • Connection types
  • Pressure classes
  • Material types


Class 150 fittings pressure rating

Temperature °F 150 1/4" 1" 11/4" 2" 2 1/2" 3"
-20 to 150° 300 2,000 1,500 1,000
200 265 1,785 1,350 910
250° 225 1,575 1,200 825
300° 185 1,360 1,050 735
350° 150 1,150 900 650
400° -- 935 750 560
450° -- 225 600 475
500° -- 510 450 385
550° -- 300 300 300


Pressure rating of class 150 flange

Temperature °F (Fahrenheit ) 150 LBS
-20 to 100 275
200 230
300 205
400 190
500 170
600 140
700 110
800 80
900 50
1000 20
1100 20
1200 20
1300 20
1400 20
1500 10

Types of Class 150 forged fittings as per ASME B16.11



Types of Class 150 flanges as per standard ASME B16.5



Class 150 flange working pressure

Temperature in Celsius (°C)
Class Pressure
Class 900 Class 1500 Class 2500 Class 150 Class 300 Class 600
-29 - 38 155 259 431 19.8 51.7 103.4
50 155 259 431 19.5 51.7 103.4
100 155 258 429 17.7 51.5 103.0
200 146 243 405 13.8 48.6 97.2
300 129 214 357 10.2 42.9 85.7
400 104 174 290 6.5 34.7 69.4
500 34.7 57.9 96.5 2.8 11.6 23.2


150 lb class flange dimensions

150 lb class flange dimensions
NPS O.D. (Inch) SORF Bore Inner Diameter (MM)
WNRF Bore Inner Diameter (MM)
Diameter Hub Base (Inch)
Minimum Wall Thickness (MM)
RF Diameter (Inch)
Bolt Holes Number Holes Diameter (MM) Bolt Circle (Inch)
1/2 3.50 9.65 22.35 15.74 1.19 1.38 4 15.74 2.38
3/4 3.88 11.17 27.68 20.82 1.50 1.69 4 15.74 2.75
1 4.25 34.54 26.67 1.94 12.7 2.00 4 15.74 3.12
1 1/ 2 5.00 49.53 40.89 2.56 15.74 2.88 4 15.74 3.88
2 6.00 61.97 52.57 3.06 17.52 3.62 4 19.05 4.75
3 7.50 90.67 77.97 4.25 22.35 5.00 4 19.05 6.00
4 9.00 116.07 102.36 5.31 22.35 6.19 8 19.05 7.50
5 10.00 143.7 128.2 6.44 22.35 7.31 8 22.35 8.50
6 11.00 170.68 154.17 7.56 23.87 8.50 8 22.35 9.50
8 13.50 221.48 202.69 9.69 26.92 10.62 8 22.35 11.75
10 16.00 276.35 254.50 12.00 28.44 12.75 12 25.4 14.25
12 19.00 327.15 304.8 14.38 30.22 15.00 12 25.4 17.00
16 23.50 410.46 387.35 18.00 35.05 18.50 16 28.44 21.25
18 25.00 461.77 438.15 19.88 38.1 21.00 16 31.75 22.75
20 27.50 513.08 488.95 22.00 41.14 23.00 20 31.75 25.00
22 29.50 564.38 539.75 24.25 44.45 25.25 20 35.05 27.25
24 32.00 615.95 590.55 26.12 45.97 27.25 20 35.05 29.50


End connections types of class 150 pipe fittings

Connection Type of SS Forged Fittings
Female x Female Straight Coupling
​Female x Female 90 Deg and 45 Degree Elbow
Female x Female x Female Reducing/ Equal Tee
​Female x Female Union
Female NPT Cap
​​​Female x Male 90 Deg and 45 Degree Street Elbow
Male Hexagon Plug
Male x Male Hexagonal Nipple
​Female x Male hexagon Bush
Female Half Coupling


Difference between BSP and NPT threads in class 150 threaded fittings

Difference between BSP and NPT threads in class 150 threaded fittings


ANSI B16.5 class 150 forged flanges available in RTJ/ RF/ FF face types



Face types of class 150 pipe flange

Characteristics FF (Flat Face) RF (Raised Face) RTJ (Ring Type Joint)
Types Of Gasket Non-metallic and Soft gasket Semi-metallic and Non-metallic gasket Hard metal gasket
Area Of Sealing Large Medium Small
Pressure Class Class 125 to Class 250 Class 150 To 2500 Class 150 To 2500 Generally ≥ 900 LBS
Range Of Temperature Only for low temperatures Broad range Broad range
Range Of Pressure only for low pressures Broad range only for higher pressures
Face Sealing I.D. to O.D. I.D. to raised face O.D.. Groove in face.


Class 150 flange bolt chart

class 150 flange bolt chart
NPS Flange Diameter (Inch) Bolt Holes Diameter(MM) Bolt Circle (Inch) Bolts Number
Bolts Diameter(MM)
1/4 3-3/8 15.74 2-1/4 4 12.7
1/2 3-1/2 15.74 2-3/8 4 12.7
3/4 3-7/8 15.74 2-3/4 4 12.7
1 4-1/4 15.74 3-1/8 4 12.7
1-1/4 4-5/8 15.74 3-1/2 4 12.7
1-1/2 5 15.74 3-7/8 4 12.7
2 6 19.05 4-3/4 4 15.87
2-1/2 7 19.05 5-1/2 4 15.87
3 7-1/2 19.05 6 4 15.87
3-1/2 8-1/2 19.05 7 8 15.87
4 9 19.05 7-1/2 8 15.87
5 10 22.35 8-1/2 8 19.05
6 11 22.35 9-1/2 8 19.05
8 13-1/2 22.35 11-3/4 8 19.05
10 16 25.4 14-1/4 12 22.22
12 19 25.4 17 12 22.22
14 21 28.44 18-3/4 12 25.4
16 23-1/2 28.44 21-1/4 16 25.4
18 25 31.75 22-3/4 16 25.4
20 27-1/2 25 20 25.4 31.75
24 32 35.05 29-1/2 20 25.4


Class 150 flange gasket dimensions

NPS O.D. I.D.
DN Class 150 Flanges Inner Diameter
15 48 21
20 57 27
25 67 33
32 76 42
40 86 48
50 105 60
65 124 73
80 137 89
90 162 102
100 175 114
125 197 141
150 222 168
200 279 219
250 340 273
300 410 324
350 451 356
400 514 406
450 549 457
500 606 508
600 718 610


Read in detail about class 150 threaded fittings Non-destructive testing to ensure leak-free connection


Non-destructive testing for class 150 socket weld fittings

  • MPI (Magnetic particle inspection)
  • DPI (Dye penetrant inspection)
  • RT (Radiographic testing)
  • UT (Ultrasonic testing)

Class 150 flange weight

Normal Pipe Size Slip
On (LBS)
Threaded (KG) Socket
Weld (LBS)
Lap
Joint (KG)
Blind (LBS) Weld
Neck (KG)
1/2 1.10 0.5 1.98 0.5 1.98 0.9
3/4 1.98 0.9 1.98 0.9 1.98 0.9
1 1.98 0.9 1.98 0.9 1.98 1.4
3.08 1.4 3.08 1.4 3.08 1.4
3.08 1.4 3.08 1.4 3.96 1.8
2 5.07 2.3 5.07 2.3 5.07 2.7
7.9 3.6 7.93 3.6 7.05 4.5
3 9.03 4.1 9.03 4.1 9.03 5.2
8.81 5.4 8.81 4 13.00 5.4
4 13.00 5.9 13.00 5.9 16.97 7.4
5 14.99 6.8 14.99 6.8 19.84 9.5
6 18.95 8.6 18.95 8.6 26.89 11.7
8 29.76 13.5 29.76 13.5 46.73 18.9
10 42.76 19.4 42.76 19.4 69.44 24.3
12 63.49 28.8 63.49 28.8 122.13 39.6
14 89.28 40.5 89.28 47.3 138.8 51.3
16 105.16 44.1 97.22 63 178.57 63
18 128.97 58.5 128.97 72 218.25 74.3
20 163.80 74.3 163.80 87.8 282.85 88.7
22 183.64 83.3 183.64 110.3 352.29 101.3
24 218.25 99 218.25 123.8 426.59 120.6

Class 150 flange thickness in mm

NPS SCH 20 SCH 80 SCH 120
½ - 0.14 -
¾ - 0.15 -
1 - 0.17 -
1 ¼ - 0.19 -
1 ½ - 0.20 -
2 - 0.21 -
3 - 0.30 -
4 - 0.33 0.43
5 - 0.37 0.50
6 - 0.43 0.56
8 0.25 0.50 0.71
10 0.25 0.59 0.84
12 0.25 0.68 1
14 0.31 0.75 1.09
16 0.35 0.84 1.21
18 0.36 0.93 1.37
20 0.40 1.03 1.50
22 - - -
24 0.45 1.21 1.81


View the documentation requirements of class 150 pipe fittings for high-pressure applications


Documentation requirements for class 150 stainless steel fittings

  • Heat treatment charts
  • Welding procedure specification
  • Raw material test reports
  • Welding procedure specification
  • MTC test reports


What is the pressure a class 150 socket weld fittings can handle?

The working pressure that the class 150 socket weld fittings can withstand is 150 PSI.


What are the types of connections for Class 150 forged fittings?

Two connections types availablea

  • National Pipe Thread (NPT)
  • British Standard Pipe Thread (BSPT)


​Can NPT and BSPT threads used together in a class 150 screwed fittings? Why?

Can NPT and BSPT threads used together in a class 150 screwed fittings? Why?