Armaflex Class O insulation tube 2.1/8 OD x 3/4 WT Black

Pipe systems and fittings are the pipe, joints, valves and accessories that carry water, heating water and gas around a building. The range runs from copper press fittings and brass threaded parts to flexible gas hoses and large flanged valves.

Pipe materials

• Copper: seamless copper tube for hot and cold water, heating and gas is made to BS EN 1057 and sized by outside diameter.
• PVC-U and ABS: rigid plastic pressure pipe joined with solvent cement. Use the cement made for that plastic, as the two types are not interchangeable.
• Polyethylene: PE pipe for water supply, above or below ground, is covered by BS EN 12201. Electrofusion fittings join it with a heating coil built into the fitting, after the pipe surface has been scraped clean.

Joints and threads

Keep to one joining method on a run where you can, and match it to the pipe: compression, press, push-fit, solder or threaded. Press fittings use different seals and markings for water, heating and gas. Threads need care: parallel threads to BS EN ISO 228-1 do not seal on the thread and rely on a washer or O-ring, while taper threads to BS EN 10226-1 seal on the thread with a jointing compound or tape.

Valves and pressure ratings

A PN figure on a valve or fitting is its nominal pressure in bar at 20°C, and the safe working pressure falls as temperature rises. Larger pipework uses flanged valves and fittings, with steel flanges made to BS EN 1092-1.

Anything used on drinking water must be suitable under the Water Supply (Water Fittings) Regulations 1999. Work on gas pipework must only be carried out by a Gas Safe registered engineer. For individual parts, browse fittings and valves.