Div 22 · IPC
Water Demand & Pipe Sizing
Enter fixture counts → Water Supply Fixture Units, peak GPM (Hunter's curve, IPC E103.3), service pipe size, and total drainage fixture units. Estimating support — the plumbing EOR verifies against the adopted code.
Fixtures
Water closet (flushometer valve) · 10 WSFU
Water closet (flush tank) · 5 WSFU
Urinal (flushometer valve) · 5 WSFU
Urinal (waterfree) · 0 WSFU
Lavatory / sensor faucet · 2 WSFU
Service / mop sink · 4 WSFU
Shower · 4 WSFU
Bottle filler / drinking fountain · 0.5 WSFU
Kitchen sink · 4 WSFU
Results
Total WSFU117
Peak demand70 GPM
Service pipe (Cu Type L, ~8 ft/s)2"
Total drainage (DFU)73
- Peak demand from Hunter's curve (IPC Table E103.3) — flushometer (flush-valve) fixtures drive high instantaneous flow vs. tank fixtures.
- Supply pipe sized at ~8 ft/s; verify available street pressure, meter size, and pressure loss (fittings + elevation). Hot-water branch is sized on the hot fraction of WSFU.
- Drainage (DFU) sizes the sanitary stack/building drain per IPC Table 710.1; confirm slope and venting.