Drainage Pipe Sizing Calculator
The Drainage Pipe Sizing Calculator picks the drain pipe diameter from the total drainage fixture units (DFU) and slope. Example: for a building drain serving 10 water closets, 8 lavatories, and 5 urinals at 2% slope, Total DFU = 68 DFU, Recommended diameter = 100 mm, Velocity = 1.34 m/s (per Philippine Plumbing Code | UPC Table 7-5).
How it works
Computed from your inputs per Philippine Plumbing Code | UPC Table 7-5.
Worked example (Plumbing & Pumps)
Inputs: a building drain serving 10 water closets, 8 lavatories, and 5 urinals at 2% slope.
| Result | Value |
|---|---|
| Total DFU | 68 DFU |
| Recommended diameter | 100 mm |
| Velocity | 1.34 m/s |
Computed live by WorkHive's calculation engine; standard: Philippine Plumbing Code | UPC Table 7-5.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses a building drain serving 10 water closets, 8 lavatories, and 5 urinals at 2% slope.
- The calculator returns Total DFU, Recommended diameter, Velocity, computed per Philippine Plumbing Code | UPC Table 7-5.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
What is a drainage pipe sizing calculator DFU?
The Drainage Pipe Sizing Calculator is a free online tool that computes picks the drain pipe diameter from the total drainage fixture units (DFU) and slope. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following Philippine Plumbing Code | UPC Table 7-5. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive's engineering calculators are free to use, no sign-up needed for the tools. WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive Drainage Pipe Sizing Calculator in WorkHive: free, no sign-up needed for the calculators.