Recommended bolt torque for AWWA Class B and Class D flanges with full face rubber gaskets, for ASTM A193 Grade B7 studs. Applies to both AWWA C207 and C228.
Instant per-flange weight
Dimensions and weights
Dimensional tolerances
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Select a gasket durometer to view the recommended torque per bolt, including gasket contact area, number of bolts, bolt size, and minimum torque.
| Nominal Pipe Size (in) | Gasket Contact I.D. (in) | Flange O.D. (in) | Bolt Hole Dia. (in) | Gasket Contact Area (sq.in.) | No. Bolts | Bolt Size (in) | Min. Gasket Stress (psi) | Min. Torque/Bolt (ft.lbs) | Max. Gasket Stress (psi) | Torque/Bolt (ft.lbs) |
|---|---|---|---|---|---|---|---|---|---|---|
| 4 | 4.57 | 9.00 | 0.75 | 43.68 | 8 | 0.63 | 600 | 32 | 900 | 49 |
| 5 | 5.66 | 10.00 | 0.88 | 48.57 | 8 | 0.75 | 600 | 40 | 900 | 60 |
| 6 | 6.72 | 11.00 | 0.88 | 54.76 | 8 | 0.75 | 600 | 45 | 900 | 68 |
| 8 | 8.72 | 13.50 | 0.88 | 78.61 | 12 | 0.88 | 600 | 65 | 900 | 98 |
| 10 | 10.88 | 16.00 | 1.00 | 98.67 | 12 | 0.88 | 600 | 63 | 900 | 94 |
| 12 | 12.88 | 19.00 | 1.00 | 143.81 | 12 | 0.88 | 600 | 92 | 900 | 137 |
| 14 | 14.19 | 21.00 | 1.13 | 176.29 | 12 | 1.00 | 600 | 131 | 900 | 196 |
| 16 | 16.19 | 23.50 | 1.13 | 211.97 | 16 | 1.00 | 600 | 118 | 900 | 177 |
| 18 | 18.19 | 25.00 | 1.25 | 211.37 | 16 | 1.13 | 600 | 129 | 900 | 193 |
| 20 | 20.19 | 27.50 | 1.25 | 249.26 | 20 | 1.13 | 600 | 122 | 900 | 182 |
| 22 | 22.19 | 29.50 | 1.38 | 267.07 | 20 | 1.25 | 600 | 144 | 900 | 216 |
| 24 | 24.19 | 32.00 | 1.38 | 314.97 | 20 | 1.25 | 600 | 170 | 900 | 254 |
| 26 | 26.00 | 34.25 | 1.38 | 354.75 | 24 | 1.25 | 900 | 239 | 900 | 239 |
| 28 | 28.00 | 36.50 | 1.38 | 389.02 | 28 | 1.25 | 900 | 224 | 900 | 224 |
| 30 | 30.00 | 38.75 | 1.38 | 430.89 | 28 | 1.25 | 900 | 248 | 900 | 248 |
| 32 | 32.00 | 41.75 | 1.63 | 506.68 | 28 | 1.50 | 900 | 309 | 900 | 309 |
| 34 | 34.00 | 43.75 | 1.63 | 529.01 | 32 | 1.50 | 900 | 282 | 900 | 282 |
| 36 | 36.00 | 46.00 | 1.63 | 577.66 | 32 | 1.50 | 900 | 308 | 900 | 308 |
| 38 | 38.00 | 48.75 | 1.63 | 666.07 | 32 | 1.50 | 900 | 356 | 900 | 356 |
| 40 | 40.00 | 50.75 | 1.63 | 691.54 | 36 | 1.50 | 900 | 328 | 900 | 328 |
| 42 | 42.00 | 53.00 | 1.63 | 746.08 | 36 | 1.50 | 900 | 354 | 900 | 354 |
| 44 | 44.00 | 55.25 | 1.63 | 793.99 | 40 | 1.50 | 900 | 339 | 900 | 339 |
| 46 | 46.00 | 57.25 | 1.63 | 829.33 | 40 | 1.50 | 900 | 354 | 900 | 354 |
| 48 | 48.00 | 59.50 | 1.63 | 879.70 | 44 | 1.50 | 900 | 342 | 900 | 342 |
| 50 | 50.00 | 61.75 | 1.88 | 909.79 | 44 | 1.75 | 900 | 470 | 900 | 470 |
| 52 | 52.00 | 64.00 | 1.88 | 971.78 | 44 | 1.75 | 900 | 502 | 900 | 502 |
| 54 | 54.00 | 66.25 | 1.88 | 1035.45 | 44 | 1.75 | 900 | 535 | 900 | 535 |
| 60 | 60.00 | 73.00 | 1.88 | 1214.37 | 52 | 1.75 | 900 | 531 | 900 | 531 |
| 66 | 66.00 | 80.00 | 1.88 | 1461.77 | 52 | 1.75 | 900 | 639 | 900 | 639 |
| 72 | 72.00 | 86.50 | 1.88 | 1639.37 | 60 | 1.75 | 900 | 621 | 900 | 621 |
| 78 | 78.00 | 93.00 | 2.13 | 1787.57 | 64 | 2.00 | 900 | 695 | 900 | 695 |
| 84 | 84.00 | 99.75 | 2.13 | 2046.01 | 64 | 2.00 | 900 | 796 | 900 | 796 |
| 90 | 90.00 | 106.50 | 2.44 | 2229.01 | 68 | 2.25 | 900 | 914 | 900 | 914 |
| 96 | 96.00 | 113.25 | 2.44 | 2517.50 | 68 | 2.25 | 900 | 1032 | 900 | 1032 |
| 102 | 102.00 | 120.00 | 2.69 | 2729.87 | 72 | 2.50 | 900 | 1166 | 900 | 1166 |
| 108 | 108.00 | 126.75 | 2.69 | 3048.40 | 72 | 2.50 | 900 | 1302 | 900 | 1302 |
| 114 | 114.00 | 133.50 | 2.94 | 3275.29 | 76 | 2.75 | 900 | 1455 | 900 | 1455 |
| 120 | 120.00 | 140.25 | 2.94 | 3623.86 | 76 | 2.75 | 900 | 1610 | 900 | 1610 |
| 126 | 126.00 | 147.00 | 3.19 | 3864.11 | 80 | 3.00 | 900 | 1769 | 900 | 1769 |
| 132 | 132.00 | 153.75 | 3.19 | 4243.44 | 80 | 3.00 | 900 | 1943 | 900 | 1943 |
| 138 | 138.00 | 160.50 | 3.44 | 4495.13 | 84 | 3.25 | N/A | N/A | N/A | N/A |
| 144 | 144.00 | 167.25 | 3.44 | 4903.79 | 84 | 3.25 | N/A | N/A | N/A | N/A |
Each table lists, per nominal size: gasket contact area, number of bolts, bolt size, and torque per bolt, a minimum to reach a safe seal and a preferred (maximum) value not to exceed. Bolts are typically brought to a snug fit, then tightened in the numbered cross pattern shown in the example image, in two or three passes, ending within the min/preferred range. This even sequence helps the gasket compress uniformly rather than over-stressing one side of the flange. Re-check torque once the system reaches operating temperature.
We manufacture to your specifications and stock domestic AIS/Buy America and imported materials, with galvanized, epoxy, and additional coatings available. Rubber expansion joints and gaskets are also supplied on request.
AWWA C207 covers carbon steel flanges, while AWWA C228 covers stainless steel flanges for the same applications. Both define dimensions, pressure classes, and material requirements; Class B and Class D share the same bolt pattern and torque values across both standards.
No. AWWA states its pressure ratings are for conditions and temperatures customary in water utility service, based on maximum operating pressure plus anticipated surge, for both C207 and C228. They are not ANSI/ASME-style pressure–temperature tables.
Unless noted otherwise, the torque values on this page are for ASTM A193 Grade B7 studs at 60,000 psi bolt stress. If your project specifies a different bolt grade, confirm the correct torque with your bolting or gasket manufacturer before assembly.
API International stocks the flanges you need for your project, and our machine shop can modify stock products for special requirements. Contact API International’s experienced sales team, and we will help you select the right flange for your application.
