This 1950’s school contained vast oversized runs of pipework hidden in ducts, which also ran alongside heating pipes with possible asbestos issues.

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Through DCS conducting a Legionella Risk Assessment, it became apparent that the cold water supply, which runs from the main cold water storage tank through to the boiler house, was gaining heat up to the level of 35°C and above. As a precaution samples were taken, in which they returned showing very high levels of Legionella bacteria present.

The tests however indicated that the CWS tank and the water supply in the kitchen were found to be Legionella free. However once the cold water supply entered the boiler house area it was to be running parallel with heating pipes, with no insulation present. After leaving the boiler room the pipe work had been boxed in at a high level, for aesthetic reasons, again with no insulation. Dead legs and low use points were also found in the area.


Our first step was to remove the dead legs where possible and also two showers. Following this all the pipework from the boiler room to the shower areas was insulated.

A daily flushing regime was suggested and implemented. This measure did aid in creating satisfactory results in some areas, although positive results were being found in the swimming pool area. Also the temperature monitoring showed the temperature was not staying below 20°C. All this was a result of the swimming pool heating pipes sitting parallel with the cold water main and hitting 80°C. It was found that the only place heat transfer could happen is where the pipes went through a brick wall and insulation was not present.

End result

The swimming pool was made out of use and the heating was turned off. This resulted in the bacterial results coming back negative for Legionella. The pool heating pipes are being reviewed and it was suggested for them to be moved to a more suitable position. Regular sampling is also conducted to ensure the problem does not keep occurring.

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