MidBrass Type A MT Cock BS2879/2 1/2 Inch, brass drain cock, draw-off cock, service valve, plumbing stop valve, isolation valve

Pipe fittings join lengths of pipe, change direction, branch a run or connect pipework to taps, valves and appliances. Couplings, elbows, tees, reducers, stop ends, tap connectors and adaptors are made for each common joining method, so the first choice is how the joint will be made.

Joining methods

• Compression: a nut squeezes an olive onto the pipe. No heat is needed and the joint can be taken apart, which suits accessible positions.
• Solder ring and end feed: capillary fittings for copper tube. Solder ring fittings carry their own solder; end feed fittings need solder added while heating. Both need a flame and flux.
• Press: a pressing tool crimps the fitting onto the pipe for a quick, flame-free joint. Seals and markings differ for water, heating and gas.
• Push-fit: a grab ring and O-ring hold the pipe once it is cut square and deburred. Plastic pipe usually needs a pipe insert.
• Threaded: BSP threads connect to valves, cylinders, tanks and appliances.

Sizes, materials and standards

Copper tube is sized by outside diameter: 15mm and 22mm are the most common in homes, 8mm and 10mm suit microbore heating, and 28mm to 54mm and above serve larger runs. Copper fittings are made to the BS EN 1254 series, which has separate parts for capillary, compression, push-fit and press types. Concealed fittings on drinking water supplies should be dezincification resistant (DZR) brass or gunmetal.

Choosing the right fitting

Match the size, joining method and pipe material to the existing pipework, and check the fitting is suitable for the system's temperature and pressure. To shut off or control flow, browse valves, or see the wider pipe systems and fittings range.

Fittings on gas pipework must only be installed by a Gas Safe registered engineer.