A one-way valve, which allows air into a drainage system, found by
a basin or at the top of an internal soil pipe to balance pressures
and prevent the water in U-bends being sucked out.
A bubble of air that gets to the top section of piping and cannot
be pushed out by the pipe contents and reduces the flow of the content
of the pipe.
Sometimes if a plug of water is traveling down a drain, it will act
as a piston and lower the pressure behind it, pulling out the water
in U-bends. This is known as a back-siphon.
An item of the sanitary ware in bathrooms fed by a cistern - a closed-lid
tank located in the roof space.
The open vessel with removable lid within which the inlet of new water
is controlled by a ball float valve. Cisterns exist to maintain a
back-up water supply for toilets in the event of water failure and
to prevent back siphonage into the fresh water mains.
A copper or stainless steel pipe joint fitting that forms a seal by
internally crushing a soft copper ring onto the pipe. Easy to fit
and remove, but more expensive, unsightly and bulky than a soldered
The material used for hot and cold water pipes, generally 15mm to
basins and mains fed taps and 22mm to baths.
The soil pipe that rises vertically through a house from the drainage
connecting toilets, baths and basins.
The small open cistern, usually referred to as a tank, that feeds
the radiator water in central heating.
This is the hot water cylinder where the water for basins and baths
is heated by a coil of piping inside the cylinder or tank. The coil
of piping is connected to the central heating system and acts as a
The toilet waste outlet, which passes horizontally into the drainage
A water heating system for hot water to baths and basins which is
sealed. Instead of the vent found in a header tank, a pressure vessel
controls pressure. The advantage is that the pressure is high and
so good for showers. Current Building Regulations require that if
fitting this system, the details are submitted as a formal application
A vertical water pipe carrying the mains water supply.
The toilet waste outlet that passes vertically downwards into the
The sanitary ware in a kitchen fed by the mains cold supply direct.
A U-shaped pipe system, which maintains a residual amount of the waste
water to prevent, smells from the drains coming back into the house.
Unplasticised polyvinyl chloride, now increasingly avoided due to
environmental restrictions, but still in use for drainage pipes and