A PE100 network is a chain: the pipe can be rated for 50 years, but a single badly chosen or badly made joint can fail in five. PE pipe fittings — couplings, tees, elbows, reducers, end caps and flange adaptors — and the method used to join them decide the reliability of water and gas networks. This guide compares the three main jointing systems and shows where each one fits.
The three jointing methods at a glance
| Butt fusion | Electrofusion | Compression (mechanical) |
|---|---|---|
| How it works | Pipe ends heated on a plate and pressed together | Fitting with built-in heating wire, powered by a control unit |
| Typical sizes | 63–1000+ mm | 20–630 mm |
| Joint strength | Equal to the pipe | Equal to the pipe |
| Equipment | Butt-fusion machine, trimmer, heater plate | Electrofusion control unit, scraper, clamps |
| Use for gas | Yes | Yes (preferred for small sizes) |
| Skill level | Certified welder | Certified welder |
| Typical cost per joint | Lowest at large sizes | Higher fitting price |
When to use butt fusion
Butt fusion is ideal for long straight runs of DN 110 and above, where the machine can move along the trench. Moulded or segmented butt-fusion tees, elbows and reducers are cost-effective. Follow the welding parameters (temperature, pressure, heating and cooling times) for the pipe's SDR, and record every weld.
When to use electrofusion
Electrofusion is the best choice for:
- Tie-ins and repairs in a tight trench where a butt-fusion machine cannot fit.
- Small diameters (20–90 mm), including service connections.
- Gas networks, where tapping saddles and electrofusion couplings are standard.
- Different SDRs — electrofusion can join pipes of different wall thickness.
Key rule: scrape the pipe surface to remove oxidation, mark the insertion depth, clamp, and do not move the joint until it has cooled.
When compression fittings make sense
Compression (mechanical) fittings are quick and need no power. They suit irrigation, temporary lines, small house connections and repairs up to about 110 mm. They are not a substitute for fused joints on pressurised mains or gas lines.
Transition and flange fittings
- Stub end + backing flange (flange adaptor): connects PE pipe to gate valves, dismantling joints, pumps and flow meters.
- PE-to-steel transitions: connect buried PE to steel risers in gas and water systems.
- Tapping saddles: add a branch to a live main without shutting it down.
What to write in the BOQ
Name the jointing method together with the fitting, because it changes the price and the crew: *"PE100 fittings SDR 11, PN 16: butt-fusion moulded tees and 90° elbows for DN 160–225 (EN 12201-3); electrofusion couplings and tapping saddles for DN 63–110; stub ends with galvanised steel backing flanges (EN 1092-1) at valves; jointing by certified welders, weld records to be submitted."*
Quick selector
- Village water main 110–225 mm → butt fusion + moulded tees/elbows; electrofusion couplings for tie-ins.
- Gas service lines 20–63 mm → electrofusion tees, couplings and tapping saddles.
- Pump station connections → stub ends with steel backing flanges + dismantling joint + gate valve.
- Farm irrigation → compression fittings.
Fittings GON supplies
GON stocks adapters, couplings, tees, elbows and other connecting elements for PE, steel and flanged systems. We supplied fittings for the Banoja village water supply and for the rehabilitation of medium-pressure gas pipelines in Argveta (Zestafoni) and Kanda (Mtskheta).
Related products: Fittings & connecting elements · PE100 pressure pipes · PE gas pipes · Gate valves
Further reading: PE gas pipe for medium-pressure rehabilitation
Can I weld PE80 to PE100?
It is possible with electrofusion fittings designed for both, but follow the fitting manufacturer's instructions.
Why did my electrofusion joint fail?
The most common causes are an unscraped pipe surface, contamination, the pipe moving during cooling, or a pipe that is not fully inserted.
Do fittings have to match the pipe's SDR?
For butt fusion, yes — the walls must match. Electrofusion fittings have their own pressure rating and can join different SDRs within that rating.
Get a project quote
Send your fittings list or BOQ to sales@gon.ge or call +995 595 818 800 for a complete pipe and fittings package.
GON supplies drainage, water, gas and road-infrastructure products to contractors, utilities and IFI-funded programmes across Georgia.