The best way to combat waterborne pathogens is to treat with heat – this is why hot water services in hospitals are typically circulated above 60°C and the cold water is maintained <20°C where Legionella is dormant.
The point at which the two water supplies meet – either at a manually operated tap or a thermostatic mixing valve (TMV) – will bring dormant bacteria from the cold water supply into a section of the pipe system that cools to the ambient temperature when the manual or temperature controlled outlet is not in use. Bacteria may enter this mixed water deadleg and could proliferate if water turnover is insufficient and there is suitable nutrient in the water. To reduce this risk, it is necessary to minimise the volume of the deadleg and reduce the potential for bacteria to enter the mixed water deadleg. This can be achieved by regularly flushing the pipe system at higher velocities to remove biofilm to drain. Cold water turnover should be increased and the outlet periodically disinfected using hot water at system temperature. The HORNE Optitherm thermostatic tap with its dual function (mixed water tap and dedicated cold water tap), flushing kit and thermal disinfection adaptor can facilitate Legionella management to this level. It also facilitates best practice hand hygiene and is exceptionally easy to clean and maintain.
