What changes at 22.5 degrees
With 22.5 degree fittings, the travel is the true offset times 2.613. The run is the true offset times 2.414. Every inch of true offset costs 0.199 inch of length in a bent conduit run (shrink).
- Travel = true offset x 2.613
- Run = true offset x 2.414
- Shrink per inch of offset = 0.199 in
When to use 22.5 degrees
A 22.5 degree fitting is also called a 1/16 bend. It turns the flow only a little. That helps on drain lines, where you want smooth flow and few stoppages. Always check your local code for allowed fittings.
The price is room. For a true offset of 15 inches, the run is 36 3/16", against 15 inches at 45 degrees.
Take-off at 22.5 degrees
The catalogs list take-off for 45 degree fittings only. For PVC and copper this tool shows no table value at 22.5 degrees. Measure the center to socket bottom on your fitting and type it in. For steel, the tool scales the 45 degree value and marks it approximate.
Rise and roll pairs at 22.5 degrees
These pairs give a whole number for the true offset, so you can check your own math against them.
| Rise | Roll | True offset | Travel at 22.5° | Run at 22.5° |
|---|---|---|---|---|
| 3" | 4" | 5.00" | 13 1/16" (13.07) | 12 1/16" (12.07) |
| 6" | 8" | 10.00" | 26 1/8" (26.13) | 24 1/8" (24.14) |
| 5" | 12" | 13.00" | 34" (33.97) | 31 3/8" (31.38) |
| 12" | 9" | 15.00" | 39 3/16" (39.20) | 36 3/16" (36.21) |
| 8" | 15" | 17.00" | 44 7/16" (44.42) | 41 1/16" (41.04) |
| 24" | 7" | 25.00" | 65 5/16" (65.33) | 60 3/8" (60.36) |
Compare with the other angles
The offset is the same. Only the fitting angle changes. A smaller angle makes a longer travel and a longer run.
| Angle | Multiplier | Travel | Run | Shrink |
|---|---|---|---|---|
| 22.5° | 2.613 | 39 3/16" (39.20) | 36 3/16" (36.21) | 3" (2.98) |
| 30° | 2.000 | 30" (30.00) | 26" (25.98) | 4" (4.02) |
| 45° | 1.414 | 21 3/16" (21.21) | 15" (15.00) | 6 3/16" (6.21) |
| 60° | 1.155 | 17 5/16" (17.32) | 8 11/16" (8.66) | 8 11/16" (8.66) |
Questions
What is the multiplier for 22.5 degrees?
It is 2.613. Multiply the true offset by it to get the travel.
What is the shrink at 22.5 degrees?
About 3/16 inch for each inch of true offset (exactly 0.199).
Is 22.5 degrees the same as an 11.25 degree bend?
No. 11.25 degrees is half of 22.5. Use the custom angle field in the tool for 11.25 or any other angle.