Part 1 Ballcock / Float Valves BS1212/1
BS1212 part 1 is the British Standard number for piston type float operated valves.
Often called a "Portsmouth valve", these brass BS1212/1 float valves (also known as ballcocks, inlet valves, fill valves or ball valves) are used in WC toilet cisterns, loft / attic cold water tanks and central heating feed / expansion header tanks.
Most household applications use a 1/2 inch ballcock valve, the bigger 3/4 and 1 inch sizes are very rarely (pretty much never), found in a domestic environment.
