Pipe
8 materials and what works on each.
| For | Use | First alternative |
|---|---|---|
| Hot and cold water | Copper or PEX for most installations — PEX is faster and more freeze-tolerant, copper is more robust and takes heat without question. | PEX |
| Waste and drainage | Solvent-weld or push-fit PVC-u or polypropylene, at the right diameter and fall — and ABS and PVC cements are not interchangeable. | Push-fit polypropylene |
| Central heating | Copper, or a barrier-grade plastic pipe — non-barrier plastic lets oxygen into the system and corrodes it from the inside. | Barrier PEX or PE-RT |
| Boiler condensate | Plastic, never copper, at a generous diameter with continuous fall — and insulate any external run, because frozen condensate is the classic winter breakdown. | Larger diameter for external runs (32 mm or more) |
| Gas | Steel, copper of the right grade, or yellow MDPE underground — and in most jurisdictions only a registered installer may do the work. | Copper of the appropriate grade |
| An underground water supply | Blue MDPE for potable water, in one continuous length at the required depth, with no joints under a building. | Black MDPE / alkathene |
| Compressed air | Copper, steel, stainless or a purpose-rated aluminium or HDPE air system — never PVC, which fails explosively. | Copper |
| Irrigation | Low-density polyethylene tubing with barbed fittings for drip lines, and PVC or MDPE for buried mains. | Buried PVC or MDPE mains |
- Which pipe should I use for hot and cold water? Copper or PEX for most installations — PEX is faster and more freeze-tolerant, copper is more robust and takes heat without question.
- Which pipe should I use for waste and drainage? Solvent-weld or push-fit PVC-u or polypropylene, at the right diameter and fall — and ABS and PVC cements are not interchangeable.
- Which pipe should I use for central heating? Copper, or a barrier-grade plastic pipe — non-barrier plastic lets oxygen into the system and corrodes it from the inside.
- Which pipe should I use for a boiler condensate drain? Plastic, never copper, at a generous diameter with continuous fall — and insulate any external run, because frozen condensate is the classic winter breakdown.
- Which pipe is used for gas? Steel, copper of the right grade, or yellow MDPE underground — and in most jurisdictions only a registered installer may do the work.
- Which pipe should I use for a buried water supply? Blue MDPE for potable water, in one continuous length at the required depth, with no joints under a building.
- Which pipe should I use for compressed air? Copper, steel, stainless or a purpose-rated aluminium or HDPE air system — never PVC, which fails explosively.
- Which pipe should I use for irrigation? Low-density polyethylene tubing with barbed fittings for drip lines, and PVC or MDPE for buried mains.