PPR or GI pipes: which should you use?
Draft for review. This guide is placeholder wording that the shop has not yet approved. It will be updated before launch.
Both PPR and GI carry water in houses. They are joined differently and suit different jobs.
PPR (plastic, heat welded)
- Joined by heat welding with a PPR machine, so joints are sealed and do not leak when done properly.
- Does not rust or scale, and is used for both hot and cold water.
- Sold by outside diameter in millimetres, for example 20mm, 25mm, 32mm, 40mm, 50mm and 63mm.
- Fittings include elbows, tees, sockets, reducing sockets, unions, valves, and male and female threaded fittings (with a brass thread) to connect to taps and tanks.
GI (galvanised steel, threaded)
- Joined with threaded fittings and sealing tape or paste, and does not need a welding machine.
- Strong and good where pipes are exposed or outside.
- Sold by inch size, such as 1/2”, 3/4” and 1”. Over time it can rust or scale inside, especially with hard water.
Mixing the two
Use a male or female threaded PPR fitting with a brass thread to join PPR to GI, taps, valves and tanks. Take care that the thread sizes match (inch threads on GI, and PPR threaded fittings are listed with both sizes, for example 25mm x 3/4”).
Which one?
Ask your plumber. For new internal plumbing, many people choose PPR. GI is still common for outside runs and repairs. If you are unsure, send us your list and we will check sizes with you.