Reference tables
Look-up charts built from stable conventions — fixture units (WSFU & DFU), supply pipe capacity, drain & vent size by DFU, drain slope, gas pipe capacity, fixture flow & toilet gpf, and unit conversions.
Fixture units per fixture (WSFU & DFU)Water-supply fixture units (WSFU) and drainage fixture units (DFU) for common fixtures, as labeled IPC/UPC planning conventions — behind the pipe-sizing and drain-sizing tools.Supply pipe size vs GPM capacityNominal supply pipe sizes and their planning GPM capacity at a typical velocity, as labeled bands — behind the supply pipe size and peak-demand tools.Drain & vent pipe size by fixture unitsMinimum drain and vent pipe sizes by drainage fixture units (DFU), as labeled IPC/UPC planning bands — behind the drain-pipe-size and vent-size tools.Drain slope conventions (fall per foot)The standard drain-slope conventions — 1/4 in per foot for pipe up to 2-1/2 in, 1/8 in per foot for 3 in and larger — behind the drain-slope tool.Gas pipe capacity by size & lengthSchedule-40 gas pipe capacity (CFH) by nominal size at a 40 ft reference run, as labeled NFPA-54-style bands — behind the gas pipe size and pressure-drop tools.Fixture flow (GPM) & toilet flush (GPF)Typical fixture flow rates (GPM) and toilet flush volumes (GPF), pre and post-1994 low-flow standards, as labeled planning typicals — behind the savings tools.Plumbing unit conversionsThe fixed conversions behind the calculators: 7.48 gal per cubic foot, 1 psi = 2.31 ft of head, BTU/hr ÷ 1000 (nat gas) or 2516 (propane) = CFH, and 0.0408 × d² × L for pipe volume.