Drain Sizing Wizard — Step-by-Step DWV Sizing
What size drain pipe do I need for the number of fixtures I have?
The wizard converts each fixture to drainage fixture units (DFUs), sums them, and selects the smallest pipe whose table capacity meets or exceeds the total load. Capacities come directly from the IPC or UPC horizontal-branch and building-drain sizing tables, with the result citing the exact table used. It also enforces that the pipe is at least as large as the biggest trap on the branch.
Run the numbers for your project
Use the Drain Sizing Wizard — Step-by-Step DWV Sizing to get an exact answer for your inputs.
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