Thermcross Spares Expansion Vessel, Pressure Tank, Heating System Expansion Tank, Boiler Expansion Vessel, Replacement Expansion Vessel

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.