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Engineering
G-19
3. Piping Geometry Factor: Reducing pipe sizes for installation of a smaller than pipe size valves will reduce the
effective Cv of the valve. The greater the pipe reduction, the greater loss of Cv. Using the Adjusted Cvs for Piping
Geometry Factors chart, verify that the corrected Cv, for the valve size selected, meets or exceeds the required
Cv calculated in step 2.
Note: 3-Way Cvs have already been adjusted.
Adjusted Cvs for Piping Geometry Factors (Modulating @ 60 Degree Rotation)
Size
Pipe Size
2" 2-1/2" 3" 4" 5" 6" 8" 10" 12" 14" 16" 18" 20" 22" 24" 26"
2" 61 59 57 55 54
2-1/2" 107 104 98 94 92
3" 154 147 140 136 131
4" 274 265 255 242 235
5" 428 418 393 378 370
6" 567 545 524 510 501
8" 1,081 1,048 1,008 980
10" 1,710 1,671 1,617 1,572
12" 2,563 2,516 2,441 2,374
14" 3,384 3,338 3,258 3,182
16" 4,483 4,432 4,340 4,246
18" 5,736 5,682 5,577 5,466
20" 7,144 7,087 6,971 6,843
Adjusted Cvs for Piping Geometry Factors (On-Off @ 90 Degree Rotation)
Size
Pipe Size
2" 2-1/2" 3" 4" 5" 6" 8" 10" 12" 14" 16" 18" 20" 22" 24" 26"
2" 144 127 111 96 90
2-1/2" 282 245 187 165 154
3" 461 340 274 246 223
4" 841 664 538 442 406
5" 1,376 1,132 808 700 649
6" 1,850 1,360 1,101 988 929
8" 3,316 2,633 2,142 1,898
10" 5,430 4,487 3,667 3,219
12" 8,077 3,892 5,590 4,974
14" 10,538 9,360 7,942 6,998
16" 13,966 12,640 10,872 9,607
18" 17,214 15,902 13,962 12,454
20" 2,239 20,756 18,296 16,308
Butterfly Valves
Control Valves
Selection and Sizing