Legionella in Schools, College, University
Why is it so important to control legionella in an educational environment? The first reason is that there are vulnerable people present both the young and old with a mixture of medical backgrounds who might be exposed to legionnaires disease.
Secondly, legionella can grow in water systems and plumbing but it mostly favours temperatures between 20-50°C and stagnant water. Both of which regularly occur in schools. For example, if you are not carrying out legionella monthly temperature checks then the hot and cold water may fall within the 20-50°C temperature range without you knowing.
Is legionella testing a legal requirement?
Also, schools close periodically throughout the year leaving the school out of use or used more sparsely. This has an impact on water consumption and can lead to considerable stagnant water. This combined with poor temperatures can lead to the rapid growth of Legionella. Due to the size of schools, the stored water is often in excess of 1000L. This stored water may stagnate considerably if a regular weekly flushing regime is not implemented across holiday periods or times of infrequent use.
Is it a legal requirement to have a legionella risk assessment?
Finally, because the stored hot water in cylinders is set to 60°C, the hot water poses a risk of scalding. Therefore any areas where vulnerable people are including the young should have anti-scalding valves installed so that the temperature range is 38-43°C, also known as a Thermostatic Mixing Valve (TMV). Whilst TMVs are very effective for anti-scalding they do pose a risk of Legionella growth.
This is why they must be installed as close as possible to the sink (outlet) and within 2m of the outlet. TMVs should be serviced six-monthly to clean any debris or scale build-up in their filters, along with a temperature calibration to ensure the TMV is working correctly and annual chlorination to further disinfect the filters.