A key consideration by the NHS Hospital Facilities Management was the Legionella safety of EcoCoolers, making NHS Cooling slightly more complex than other environments. A detailed risk assessment was carried out in compliance with HSE guidelines ACOP L8. The risk at each stage of the pathway to Legionella infection is analysed. The low-risk status is achieved through the EcoCooler design and process controls which reflect the ACOP guidelines.
- Avoidance of stagnant water: An EcoCooler drains when not in cooling mode. When in cooling mode the water is continuously circulating.
- Low water operating temperature: The water in an EcoCooler circulates at the ‘wet bulb temperature’ of the ambient air. In the UK this is normally below 20°C where Legionella bacteria are considered dormant.
- Avoidance of corrosion and scaling: The all plastic construction, together with an automatic water control system, prevents corrosion or scale formation
- No production of aerosols: The ‘wetted media’ cooling pads provide pure evaporation without production of droplets.
- Maintenance: All EcoCoolers should be maintained at regular intervals.
Two side discharge EcoCoolers, in conjunction with sound attenuation, were installed on the flat roof above the outpatients’ area. These are each linked to an extraction fan to provide a balanced ventilation system. An automatic control system, linked to a thermostat, sets the fan speed and cooling mode to maintain a set point of temperature.