Keraflo valves control stored water at Emirates Stadium
The storage of the huge, but variable, requirements of cold water in the Emirates Stadium is controlled by Keraflo float-controlled valves in 10 cm supply pipes. (Photo. courtesy of Arsenal FC)
Keraflo has supplied control valves for water-storage tanks at Arsenal’s Emirates Stadium to ensure that the 130 000 litre tank prior to the booster set is filled as quickly as possible. These delayed-action valves ensure high flow rates. The 60 000-seat stadium regularly attracts capacity crowds, and the requirement for water is therefore enormous. The anticipated demand is met by a 132 m3 sectional GRP storage tank, installed by MJN Colston. The tank is of drinking-water quality and made by Balmoral Tanks. It serves all domestic cold-water outlets on the site, including extensive catering and toilet facilities, via a booster pumpset. The tank measures 11 x 3 m and is 4 m deep. It is divided along its length so that each half can be isolated for maintenance. Each side of the tank is fitted with an Aylesbury KP valve kit specified by consulting engineers Buro Happold, whose senior building-services engineer Peter Naylor explains, ‘We selected these valves, in consultant with Balmoral Tanks and Keraflo, for their ability to fill each side of the tank quickly and accurately match water-storage levels to occupancy. The KP valve kits comprise KB float valves in a valve chamber above each half of the tank and two larger in-line valves at high level on the supply pipework. The KB valves offers a fully variable differential between opening and closing water levels; changes can be made quickly by a maintenance engineer without needing any tools — making it particularly suitable for buildings with seasonal occupancy. Water discharge is via an up-and-over pipe to facilitate air-gap compliance and provide back-siphonage protection in accordance with BS 1212 Part 2. The 20 cm incoming water main was split into two 4 in supply pipes, each fitted with an Aylesbury 100 mm in-line valve. These valves are opened and closed by Aylesbury KB pilot valves due to fluctuations in the pilot line. These smaller valves are operated by transfer of weight in an actuator tube, which opens the valve in a single delayed action. Attached to the actuator is a 2 m-long chain which offers a fully variable differential between opening and closing water levels by simple adjustment of the length of chain between the actuator and the floats.
Related links:
