Drainage Pipe Sizing Calculator
Static · formula-only · worked example computed when this page was built · no live data
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, in PVC, 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. Anything the worked example does not state uses this calculator's standard default; the interactive version shows every input and lets you change it.
Worked example (Plumbing & Pumps)
Inputs: a building drain serving 10 water closets, 8 lavatories, and 5 urinals at 2% slope, in PVC.
| Result | Value |
|---|---|
| Total DFU | 68 DFU |
| Recommended diameter | 100 mm |
| Velocity | 1.34 m/s |
Computed by WorkHive's calculation engine when this page was built; standard: Philippine Plumbing Code | UPC Table 7-5.
How to use this calculator
- Read the worked example. It uses a building drain serving 10 water closets, 8 lavatories, and 5 urinals at 2% slope, in PVC and shows every number in the method.
- Follow the formula with your own figures: it returns Total DFU, Recommended diameter, Velocity, computed per Philippine Plumbing Code | UPC Table 7-5.
- To compute interactively, open the Drainage Pipe Sizing Calculator inside WorkHive's free Engineering Design suite (link below). It runs the same method with your inputs.
FAQ
What is a drainage pipe sizing calculator DFU?
The Drainage Pipe Sizing Calculator is a free online tool that 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 is free: this worked example is open to everyone, and the interactive calculator runs inside the free Engineering Design suite after a free sign-up (your work is saved to your account). 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, and a free sign-up saves your calculations, BOMs and scope-of-works to your account.