This light alloy double standpipe complies with BS 336 and is designed to fit standard UK Fire Brigade hydrants with a standard UK 64mm (2.5") female BSRT (British Standard Round Thread) inlet. The twin 64mm (2.5") instantaneous female outlets have a plastic blank plug and chain. You will also need a key and bar to open the valve on the underground hydrant.
A double check non-return valve to BS6282 Part 5 is available as an option and you are advised to check with your local Water Authority as it may be a legal requirement to use a non-return valve.
