How to choose pipes and fittings
Pipes without fittings are only half a project. PP-R welding, PEX with press, and compression PP need different tools and skills. If you mix systems “because the diameter looks similar”, you end with a leak. This guide teaches you to choose as a system.
Basics: plumbing guide. Comparison: PEX, PP or copper. Parameters: diameter and pressure. How-to: compression fitting.
Three decisions before the metre
- Material / system — PP-R, PEX, compression, threaded brass/iron.
- Diameter and PN — from the project or the existing line, not “by eye”.
- Joint type — welding, press, compression, thread. You must have the tool.
Material map with examples
| Material | When typical | Example |
|---|---|---|
| PP-R / glass fibre | Hot/cold with welding | Rozma 20×2.8 PN20, 25×3.5, Peštan 20×2.8, glass fibre — see card |
| PEX / Pexfit | Flexible runs, press system | Viega Pexfit Pro 25×2.8 |
| Compression PP | Fast joints when the type fits | Elysee 20×½″, 20×¾″ |
| Iron/brass threads | Classic threaded nodes | Atusa elbow 1/2″, galvanised |
Budget: pipe + fittings
The metre is cheap; fittings “eat” the estimate. Count elbows, tees, reducers and shut-off valves. Valves: valve guide. Drainage (another system!): drainage — do not mix HT with drinking-water PP-R.
Typical mistakes
- Mixing systems (PP-R sleeve on PEX “because it looks right”).
- Buying pipe without a fittings budget.
- Ignoring PN/SDR on the hot-water line.
- Downsizing diameter “because 25 was out of stock”.
Short path
- Pick the system — comparison.
- Read diameter/PN — parameters.
- List fittings + valves.
- If compression — read how-to.
FAQ
Can I mix brands in one system?
Only if standard/compatibility is clear. Safer: one system + its fittings.
Does compression replace welding?
Not universally. Only where the type is intended.
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