Vent Pipe Sizing Calculator
Size vent pipes based on DFU connected and developed length.
Vent Sizing Table (UPC)
Maximum developed length in feet
| DFU | 1-1/4" | 1-1/2" | 2" | 3" | 4" |
|---|---|---|---|---|---|
| 1 | 45 | 60 | 120 | 212 | 300 |
| 2 | 30 | 50 | 100 | 180 | 270 |
| 4 | - | 35 | 80 | 150 | 230 |
| 8 | - | - | 50 | 100 | 180 |
| 16 | - | - | 30 | 70 | 140 |
| 32 | - | - | - | 42 | 90 |
| 64 | - | - | - | 25 | 60 |
Venting Rules
- Vent shall not be smaller than 1-1/4" (1-1/2" IPC)
- Vent cannot be smaller than 1/2 drain size
- Individual vent connects to trap arm
- Branch vent connects 2+ individual vents
- Vent must extend 6" above flood rim before going horizontal
- Horizontal vents must slope up toward stack