Legionella Pneumophila in water

Can air conditioning cause legionnaires’ disease?

We tend to think of legionnaires’ disease as a hazard related to water tanks and plumbing systems in a building. But in certain circumstances, an air conditioning system can also become infected with the Legionella bacteria and cause a health risk.

Legionnaires’ Disease is a respiratory disorder caused by Legionella Pneumophila, a bacterium usually found in water systems, lakes, rivers and streams. When inhaled, this bacteria can cause Legionnaires’ Disease. In 10 to 15% of cases, it can be fatal.

Legionnaires’ disease – a growing public health problem

According to the latest published figures for a full year from Public Health England, there were 503 reported cases of legionnaires’ disease in 2019 in England and Wales.

Although data is still being compiled, it appears that the number of people affected by legionnaires’ disease is on the rise. This may be attributed to the Covid-19 pandemic. This is because many public buildings and workplaces were closed during periods of lockdown. Upon reopening, many water storage tanks had stagnated, creating more optimal conditions for the Legionella bacteria to thrive.

It is also thought that climate change is having an impact. Legionella can survive within a temperature range broadly between 20 and 50 degrees Celsius. When water temperatures are around 37.5°C the bacteria proliferate. The numbers and severity of cases of Legionnaires’ disease increase during the summer months but with global warming causing hotter days and extended milder temperatures through spring and autumn, cases are likely to continue to increase.

So can air conditioning cause Legionnaires’ disease?

The risks of contracting Legionnaires’ disease from air conditioning are minimal. Legionella Pneumophila breeds in water and not usually in air conditioning vents. However, as the disease is caused by inhaling the bacteria it is possible to do so by breathing in infected mist. This is only really likely if:

  • The air conditioning system uses a water-based system to cool a refrigerant which then becomes infected with the Legionella bacteria.
  • Legionella bacteria are present elsewhere in the building which can contaminate water in the air conditioning system.

Reducing the risk of Legionnaires’ disease from air conditioning systems

Ensuring staff and visitors to a building are not at risk of contracting Legionnaires’ disease from air conditioning systems is relatively simple. It’s a case of implementing a regular cleaning and maintenance schedule.

Those in charge of commercial and public premises are ultimately responsible for the health and safety of everyone in the building. This brings a duty to have the air conditioning system regularly inspected and maintained.

Brooktech offers professional air conditioning services across Manchester, Stockport and the Greater Manchester areas. Keep on top of the maintenance of your cooling systems with our regular servicing plans.

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