OhMyCalc

Fixture Units Calculator

Calculate total drainage fixture units (DFU) and minimum drain pipe diameter based on plumbing fixture counts.

How to Use the Fixture Units Calculator

  1. Enter the count of each fixture type.
  2. Click Calculate for total DFU and minimum pipe diameter.

Casos de Uso

Fórmula

DFU: toilet=4, sink=1, shower=2, bathtub=3, dishwasher=2, washing machine=3. Pipe size from IPC table.

Preguntas Frecuentes

What is a fixture unit?
A drainage fixture unit (DFU) is a measure of probable wastewater flow. 1 DFU ≈ 28 L/min.
What pipe sizes do different DFU totals require?
0–3 DFU: 50mm. 4–10: 75mm. 11–30: 100mm. 31–60: 125mm. >60: 150mm.
Are these values for horizontal or vertical pipes?
These are for horizontal branch drains. Vertical stacks and building drains may differ.