Recommended bolt torque for ANSI/ASME B16.47 Series A Class 150 flat face flanges with full face rubber gaskets, for ASTM A193 Grade B7 studs.
Instant per-flange weight
Dimensions and weights
Dimensional tolerances
Request a Product Catalog
Select a gasket durometer to view the recommended torque per bolt, including flange outside diameter, bolt hole diameter, number of bolts, bolt size, and minimum and preferred torque.
| Nominal Pipe Size (in) | Gasket Contact I.D. (in) | Flange O.D. (in) | Bolt Hole Dia. (in) | No. Bolts | Bolt Size (in) | Max. Gasket Stress Avail. (psi) | Min. Rec'd Gasket Stress (psi) | Min. Rec'd Torque/Bolt (ft.lbs) | Max. Rec'd/Avail. Gasket Stress (psi) | Preferred Torque/Bolt (ft.lbs) |
|---|---|---|---|---|---|---|---|---|---|---|
| 26 | 26.00 | 34.25 | 1.38 | 24 | 1.25 | 3774 | 900 | 238 | 900 | 238 |
| 28 | 28.00 | 36.50 | 1.38 | 28 | 1.25 | 4015 | 900 | 224 | 900 | 224 |
| 30 | 30.00 | 38.75 | 1.38 | 28 | 1.25 | 3622 | 900 | 248 | 900 | 248 |
| 32 | 32.00 | 41.75 | 1.62 | 28 | 1.50 | 4655 | 900 | 309 | 900 | 309 |
| 34 | 34.00 | 43.75 | 1.62 | 32 | 1.50 | 5095 | 900 | 283 | 900 | 283 |
| 36 | 36.00 | 46.00 | 1.62 | 32 | 1.50 | 4667 | 900 | 309 | 900 | 309 |
| 38 | 38.00 | 48.75 | 1.62 | 32 | 1.50 | 4048 | 900 | 356 | 900 | 356 |
| 40 | 40.00 | 50.75 | 1.62 | 36 | 1.50 | 4386 | 900 | 328 | 900 | 328 |
| 42 | 42.00 | 53.00 | 1.62 | 36 | 1.50 | 4065 | 900 | 354 | 900 | 354 |
| 44 | 44.00 | 55.25 | 1.62 | 40 | 1.50 | 4244 | 900 | 339 | 900 | 339 |
| 46 | 46.00 | 57.25 | 1.62 | 40 | 1.50 | 4063 | 900 | 354 | 900 | 354 |
| 48 | 48.00 | 59.50 | 1.62 | 44 | 1.50 | 4214 | 900 | 342 | 900 | 342 |
| 50 | 50.00 | 61.75 | 1.88 | 44 | 1.75 | 5750 | 900 | 470 | 900 | 470 |
| 52 | 52.00 | 64.00 | 1.88 | 44 | 1.75 | 5383 | 900 | 502 | 900 | 502 |
| 54 | 54.00 | 66.25 | 1.88 | 44 | 1.75 | 5051 | 900 | 535 | 900 | 535 |
| 56 | 56.00 | 68.75 | 1.88 | 48 | 1.75 | 5110 | 900 | 528 | 900 | 528 |
| 58 | 58.00 | 71.00 | 1.88 | 48 | 1.75 | 4817 | 900 | 561 | 900 | 561 |
| 60 | 60.00 | 73.00 | 1.88 | 52 | 1.75 | 5090 | 900 | 530 | 900 | 530 |
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.
Flat face flanges with full face rubber gaskets only, that's the only facing and gasket combination published for ANSI/ASME B16.47. For raised face or compressed sheet torque, see the ANSI/ASME B16.5 Class 150 or Class 300 Torque Chart.
Bolt count and bolt size are set by the flange standard and class alone, but torque is a joint calculation: it depends on the gasket's contact area, its minimum and maximum recommended compressive stress, and the bolt's own stress limit. Two different gaskets on the identical flange can call for very different torque, which is why this chart is organized by gasket type first. For bolt count and size, see the ANSI/ASME B16.47 Bolt & Stud Chart. For bolt count and size, see the ANSI/ASME B16.47 Bolt & Stud Chart.
The source table is published for both standards together, ANSI/ASME B16.5 Class 150 through 24 inch, and ANSI/ASME B16.47 Series A Class 150 from 26 inch up. This page shows only the B16.47 range; see the ANSI/ASME B16.5 Class 150 Torque Chart for sizes 24 inch and under.
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.
These values are engineering data for rubber and compressed sheet gaskets. A different manufacturer's gasket can have a different recommended stress range, so treat these numbers as a starting reference and confirm torque with that 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.
