Impact of the COVID-19 lockdowns on the risk from legionella bacteria

Importance of health and safety and wellbeing of the staff, visitors and the public has been a focus and priority of many employers and building owners. Even more now, when we all are being affected by the pandemic. When tackling the spread of the virus it is easy to lose focus on our general day to day obligations.

As our work patterns, movements and behaviour change, this can have a significant impact on aspects of the safety of our properties, and this includes the risk associated with legionella bacteria. Health and Safety Law continues to apply, and duty holders still maintain a legal obligation to protect those in and around their properties from exposure to legionella bacteria both now and in the future.

Legionella bacteria can grow at temperatures between 20°C and 45°C, where a suitable nutrient is available and where turnover of water is low. As businesses increasingly move to a home-working model, the demand for water in many commercial buildings will be significantly reduced. As the water usage is reduced, the risk of low turnover and stagnation increases.

Hot and cold water systems

The main risk to hot and cold water systems caused by the ongoing coronavirus pandemic is the reduction in demand for water. Water usage should be closely monitored during this period, and the volume of stored water in cold water storage tanks should be reduced where possible, to ensure complete daily turnover is maintained.

Weekly flushing regimes must be reviewed and continued where possible, to ensure that all water services which are infrequently used are included. For many buildings this may include all facilities.

Poor turnover of water can lead to increase of temperatures in cold water systems. This can be particularly significant in large, high rise buildings and complex water systems. Temperature monitoring should continue and, where issues are identified, the frequency of flushing and temperature monitoring should be increased as necessary to maintain cold water systems below 20°C.

It is important that all routine maintenance tasks advised by your assessment continue in line with ACoP L8 and HSG274 Part 2. In multi-occupancy buildings, tenants should be contacted to ensure they continue to fulfil their obligations with regard to legionella control, including at least weekly flushing of all infrequently used water services.

However, as the government implemented strict new measures to tackle the spread of coronavirus, it may be difficult to fulfil all maintenance and monitoring tasks. We advise to implement additional control measures, these may include locking showers or removing shower heads to prevent aerosol generation, additional flushing without the release of aerosols and increased microbiological sampling.

When all of the above cannot be completed, you should contact your Legionella Services provider for advice on how to safely shut down and re-start the system when we are ready to resume normal life.

If you require further information or advice regarding legionella control, or have concerns specific to maintaining the risks associated with legionella bacteria during the coronavirus pandemic, please contact us at RM.

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