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PPR Pipe Sizes Explained: Diameter Chart 20–160mm
PPR pipes are sized by metric outer diameter, from 20mm up to 160mm and beyond. This guide explains the size system, wall thickness classes, and how to choose the right diameter for your water supply project.
Understanding PPR Sizing
PPR pipe is specified by its outside diameter (OD) in millimeters — unlike steel pipe, which is often specified by nominal bore. The standard sizes follow a metric progression: 20, 25, 32, 40, 50, 63, 75, 90, 110, 125, 140, 160mm. The OD is the critical dimension because fittings and fusion tools are matched to it. The nominal pipe size conventions differ between metric thermoplastics and imperial metal pipe — a common source of confusion.
PPR Diameter Chart (20-160mm)
| OD (mm) | Common Use | Approx. Imperial Equivalent |
|---|---|---|
| 20 | Fixture branches, sinks, showers | 1/2″ (nominal) |
| 25 | Residential branches, appliances | 3/4″ (nominal) |
| 32 | Main residential risers | 1″ (nominal) |
| 40 | Large residential, small commercial | 1-1/4″ |
| 50 | Commercial branches | 1-1/2″ |
| 63 | Commercial mains | 2″ |
| 75 | Building distribution | 2-1/2″ |
| 90 | Large building mains | 3″ |
| 110 | Main supply lines, risers | 4″ |
| 160 | Large commercial / industrial | 6″ |
Metric vs Imperial Equivalents
Wall Thickness & SDR
For each diameter, PPR pipe is available in wall thickness classes tied to pressure ratings. The relationship is expressed as SDR (Standard Dimension Ratio) — the ratio of outside diameter to wall thickness. Lower SDR = thicker wall = higher pressure rating. Common SDR values: SDR11 (PN20, thickest), SDR7.4 (PN25), SDR17 (PN10), SDR13.6 (PN16). A PN20 25mm pipe and a PN10 25mm pipe have different wall thicknesses and different flow capacities.
How to Choose the Right Size
Select diameter based on: flow demand, pipe length, pressure, and acceptable pressure loss. Larger diameters allow higher flow and lower pressure loss but cost more. Standard guidance: fixture branches 20-25mm; apartment risers 32-40mm; building mains 50-75mm; large supply lines 90-160mm. Use a pipe sizing calculator or consult a plumbing engineer for critical systems. Fenilo provides complete PPR system solutions with matched pipe, fittings, and valves across all sizes.
Common Residential Sizes
- 20mm — most common for sink, shower, and toilet branches
- 25mm — main riser feeding multiple fixtures, washing machines
- 32mm — apartment main lines, larger residential systems
Commercial & Large Sizes
Commercial and industrial projects use 50mm-160mm pipes for main distribution, risers, and supply lines. These large sizes require heavier fusion equipment and longer heating times. When specifying large-diameter PPR, work with a supplier that carries the full range and can match valves, fittings, and brass transition components to the pipe class. Fenilo supports commercial PPR projects with full-size availability.
FAQ
What are the standard PPR pipe sizes?
Standard PPR outer diameters: 20, 25, 32, 40, 50, 63, 75, 90, 110, 125, 140, and 160mm. Larger sizes are available for industrial projects.
Is 20mm PPR pipe the same as 1/2 inch?
In the trade it is often called 1/2 inch, but 20mm is the actual outside diameter. It is a nominal equivalence, not a physical match to imperial 1/2-inch pipe.
What does SDR mean in PPR pipe?
SDR (Standard Dimension Ratio) is the ratio of pipe OD to wall thickness. Lower SDR means a thicker wall and higher pressure rating (e.g., SDR11 = PN20).
What size PPR pipe do I need for a house?
Typical residential systems use 20-25mm for fixture branches and 32-40mm for main risers. Size selection depends on flow demand and pressure requirements.