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Keeping water healthy, safe and sustainable in commercial buildings and estates

Recent research* has shown that UK workers are now going into the office an average of just 1.5 days a week, with only 13% going in on a Friday, suggesting average attendance is 29% with a peak of 39% mid-week. This hybrid-working hangover from the pandemic looks set to continue and poses significant challenges to keeping water supplies in our buildings safe.   

Neil Weston, Sales Manager of Keraflo, the leading developers, designers and manufacturers of electronic tank management systems and delayed action mechanical float valves, comments: “We currently have the perfect storm of a number of elements coming together to threaten the safety of cold water in commercial tanks across the UK: the flexing use of workplaces with footfall way down on pre-COVID levels; seasonally lower building occupancy in schools and universities; hikes in the seasonal use of hotels and leisure facilities; and finally, in the last few weeks, the national drought emergency amidst soaring temperatures. All of these factors present significant challenges in terms of water safety and sustainability to facilities managers looking after and refurbishing buildings, and to architects, specifiers and consulting engineers planning new buildings. 

“It’s not rocket science. During times when a building is not in use to its usual capacity, there is an increased risk of water stagnating in storage tanks. These are not necessarily being monitored or controlled and this creates an environment that is ideal for bacteria to thrive. The single most important aspect with any water storage tank is that water should be turned over every 24 hours as a minimum. Keraflo’s unique range of WRAS approved delayed action float valves, help keep water turning over and can lower water levels in tanks if required.  

“Taking this one step further, our Tanktronic system not only monitors the water in a tank, but it provides alarms for high and low water levels, and temperatures to the BMS and or/other third party devices. Using the holiday functions, you can have different water levels for different times of the year or even weekends, thereby matching capacity to demand. You can even take the guesswork out of sizing the tank and ensure turnover by using one of the holiday settings so that you empty most of the tank before refilling at regular intervals, e.g. once a week. As a recent reference, to address their key challenges with water management between seasons, Wimbledon has recently installed our KB valves to manually vary the water capacity to meet demand, and Tanktronic to monitor the water temperature.  

Balancing Twin Tanks  

“When it comes to water safety, the Keraflo team is often asked how to approach the tricky subject of balancing twin tanks. For many years now the water industry has been installing tanks with either a division or two tanks to feed a building. This allows for the maintenance or cleaning and chlorinating of the tanks, whilst leaving an uninterrupted supply to the building. This can, however, lead to problems with stagnation in one side of the tank if one float valve is favoured over the other, and in extreme circumstances a bio film can form. To overcome this, WRAS (Water Regulations Advisory Scheme) recommend the use of a Delayed Action Float Valve.  ”Where interlinked storage cisterns are used to supply drinking water, stagnation of water in some parts of the cisterns may cause the quality of the water to deteriorate. The use of Delayed Action Float Valves may help minimise the risk of stagnation” 

“Keraflo recommends the two unique solutions as detailed above. Our unique, UK manufactured KP Twin Float Valve kit is specifically designed for twin tank/partitioned tanks. It uses a KB delayed action pilot valve in each tank or division. As the water level drops, whichever pilot valve opens first actuates the main control valve filling both sides simultaneously whilst still giving the option of isolating one tank or division leaving the other side in service.  Stagnation can also be overcome using Keraflo’s Tanktronic in conjunction with our filling valve. It is installed in a similar way to the KP solution, but instead of using KB pilot valves, the two pressure sensors control the main filling valve or valves ensuring both tanks/divisions are filled simultaneously and as with the KP, still allowing one side to be isolated.  

“Keraflo’s heritage is rich, and we have many varied installations in the commercial, leisure and education markets, including Wembley Stadium, Wimbledon, Arsenal’s Emirates Stadium, MOD sites, hospitals and Universities. Suitable for retrofit and refurbishment, as well as new constructions, our unique range of products ensure water safety and sustainability. We are proud to continue our commitment to providing compliant solutions that offer the same failsafe, long-life operation that is the hallmark standard in cold water tank management for the UK.” 


For a selection of case studies, 

For more technical and pricing information, call us on 0118 921 9920 or visit  

*Source: Consultancy Advanced Workplace Associates July 2022 





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