Summer is a time most of us look forward to. Sunshine, warm weather and approaching holidays. But the arrival of Summer weather also presents a hidden danger to your building’s water systems. The warmer the weather, the warmer the water in your building’s water system. And this kind of warm water is a perfect breeding ground for the Legionella bacteria.
Legionella Bacteria: Explained
Legionella bacteria is a type of bacteria commonly found in water systems. Typically, the bacteria is harmless. However, when the bacteria is dispersed by an aerosol through facilities such as a shower, humidifier or air conditioner, it can be breathed into the lungs and cause infection.
This infection can lead to a type of pneumonia known as Legionnaires’ disease, with a fatality rate of 10-25%. Legionnaires’ disease outbreaks represent a significant, and often highly disruptive, public health threat.
Businesses that have water systems within their premises have to ensure their systems are compliant. However, during Summer extra attention has to be paid as the risk is greater.
How Legionella Bacteria Grows
The two key factors for Legionella bacteria growth are temperature and flow. Stagnant warm water is the ideal environment for Legionella to multiply and thrive.
The ideal temperature growth range is 20°C to 45°C. Below 20°C, the Legionella bacteria is considered dormant and in a controlled state. Above 45°C, it is no longer multiplying and above 60°C it is eliminated entirely.
Therefore, storing water either below 20°C or above 60°C is the key task for organisations. An organisation that acts on their legionella control responsibilities will already be doing this. But with the Summer heat, their usual systems can get disrupted.
The Hidden Summer Threat
With the Summer hot weather, buildings are warmed by the sun, and that warmth can spread into water systems. Potentially raising cold water storage temperatures above their safe 20°C limit.
What was once a controlled environment can become a breeding ground for Legionella bacteria – without anyone in the building even realising it.
The reality is that as Summers in the UK become warmer, the Legionella threat grows. Even organisations with the most regimented approach to Legionella control are at risk from this increased threat.
Summer can also lead to other changes in buildings. If a building shuts down for the Summer, such as a School or University, large parts of the water system will become unused. Taps are no longer being used, and toilets are no longer flushed. This leads to a severe slowdown of water cycling and increasing fluid stagnation.
These two factors combined can cause a real increase in Legionella threat for organisations big and small. Compliance tasks should not cease just because the building’s use has.
Combatting Legionella Bacteria in the Summer
Proactively testing the temperature of water systems, especially during exceptionally hot weather and heatwaves, is a great first step.
Water tanks, dead legs, showers, taps, TMVs and pipework are usually the main threat area for warming water in the Summer months. So paying close attention to particular parts of the water system which are liable to warm up can give extra clarity.
If a building has shut down for a Summer recess, make sure that building maintenance continues. Periodically run, empty and flush water systems at regular intervals. Turn the task into a straightforward, but vital process to make sure every water feature and system is run properly.
Next Steps
First steps should include devising and following a flushing routine which should be recorded within your Logbook along with regular temperature checks. Regular sampling can also assist during warmer months to evidence the flushing routine is sufficient.
If the temperatures continually come back too warm, you may need to schedule a Legionella risk assessment to help identify the cause.