Orifice Plate Thickness and Maximum Allowable Differential Pressure Based on the Structural Limit
Nominal Pipe Size (NPS) (inches)
Published Inside Pipe Diameter (inches)
Minimum
Maximum
2
1.687
0.115
0.130
0.125
1000
1000
1.939
0.115
0.130
0.125
1000
1000
2.067
0.115
0.130
0.125
1000
1000
2.300
0.115
0.130
0.125
1000
1000
2.624
0.115
0.130
0.125
1000
1000
2.900
0.115
0.130
0.125
1000
1000
3.068
0.115
0.130
0.125
1000
1000
3.152
0.115
0.130
0.125
1000
1000
3.438
0.115
0.130
0.125
1000
1000
3.826
0.115
0.130
0.125
1000
1000
4.026
0.115
0.130
0.125
1000
1000
4.897
0.115
0.163
0.125
345
1000
5.187
0.115
0.163
0.125
345
1000
5.761
0.115
0.192
0.125
345
1000
6.065
0.115
0.192
0.125
345
1000
7.625
0.115
0.254
0.250
1000
1000
7.981
0.115
0.319
0.250
1000
1000
8.071
0.115
0.319
0.250
1000
1000
3
4
6
8
10
12
16
Orifice Plate Thickness E (inches)
Maximum Maximum Allowable Allowable ∆P(In. H2O) ∆P(In. H2O) Recommended Orifice Fitting Orifice Flanges
9.562
0.115
0.319
0.250
570
1000
10.020
0.115
0.319
0.250
570
1000
10.136
0.115
0.319
0.250
570
1000
11.374
0.175
0.379
0.250
285
1000
11.938
0.175
0.398
0.250
285
1000
12.090
0.175
0.398
0.250
285
1000
14.688
0.175
0.490
0.375
465
1000
15.000
0.175
0.500
0.375
465
1000
Orifice Plate Thickness and Maximum Allowable Differential Pressure Based on the Structura l Limit Nominal Pipe Size (NPS) (inches) 20
24
30
Published Inside Pipe Diameter (inches)
Minimum
Maximum
Recommended
15.025
0.175
0.500
0.375
465
1000
18.812
0.240
0.505
0.375
235
1000
19.000
0.240
0.505
0.375
235
1000
19.250
0.240
0.505
0.375
235
1000
22.624
0.240
0.505
0.500
360
1000
23.000
0.240
0.562
0.500
360
1000
23.250
0.240
0.562
0.500
360
1000
28.750
0.370
0.562
0.500
180
1000
29.000
0.370
0.578
0.500
180
1000
29.250
0.370
0.578
0.500
180
1000
Orifice Plate Thickness E (inches)
Maximum Maximum Allowable Allowable ∆P(In. H2O) ∆P(In. H2O) Orifice Fitting Orifice Flanges
Used by the permission of the copyright holder, American Gas Association. Reproduced courtesy of the American Petroleum Institute.