Claudia Calder discusses the risks of Legionella when re-opening your workplace after COVID-19 and how to control it.
As places of work and businesses start to re-open, the main focus of information is how to keep your staff safe with hygiene and physical distancing control measure, but are there any other areas that you need to be aware of? One of them is your water systems and the control of Legionella Bacteria.
In this article, we discuss what businesses should be considering when opening a building, after a prolonged period of shutdown.
What are Legionella Bacteria and what does it cause?
Legionella Bacteria are a living organism found in low numbers in natural aquatic environments, e.g. lakes, rivers and ground water, and can be found globally. Since legionella bacteria are widespread in the environment, they may also contaminate and grow in purpose-built water systems such as cooling towers, evaporative condensers, hot and cold-water systems and whirlpool spas.
They love temperatures of 25°C to 45°C because these are their optimal growth conditions, where bacterial enzyme activity is most efficient.
Legionella Bacteria, or Legionella pneumophilia cause Legionellosis, the collective name given to the pneumonia-like illness caused by the bacteria. The most serious disease caused by these bacteria is Legionnaires’ disease, but they can also cause conditions of Pontiac fever and Lochgoilhead fever.
Legionnaires’ disease is a potentially fatal form of pneumonia and everyone is susceptible to infection.
However, some people are at higher risk, including those of the age of 45, smokers and heavy drinkers, people suffering from chronic respiratory or kidney disease and anyone with an impaired immune system.
Are their increased risks of Legionella in my workplace since COVID-19 lockdown?
This depends on whether you have been managing your Legionella schedule.
If your water systems have been in use and you have been carrying out your flushing in accordance with your risk assessment, then, in theory, you should be fine.
However, if you have left your building empty with nobody looking after your water systems, then you will need to do some work before you bring your staff back into the building.
First things first, review your Legionella Risk Assessment and consider carrying out water testing.
Water systems that have been shut down, or have had low water usage, or modified control regimes during the COVID-19 lockdown, may result in an increased risk of Legionella bacteria being present.
Such systems may have been out of use for a significant period and in most cases cannot be simply used straightaway.
The water system may need recommissioning as if new. Prior to return to use and the reopening of the building the water system may be brought back in to service by:
- Thorough flushing and/or;
- Cleaning and disinfection and/or;
- Controlled flushing of outlets such as taps, showers and toilets
Wet cooling systems (wet evaporate cooling mode), which have been shut down, will require recommissioning by a competent person prior to re-use.
Additional Guidance on Legionella
For further guidance on Legionella risks, see the below information from the HSE and the European Study Group for Legionella Infections:
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