Controlling Legionella in Cooling Towers with Effective Risk Management
From a legionella risk management perspective wet cooling towers and evaporative condensers (equipment that use water as part of the cooling process) are considered high risk for various reasons. They have the ability to create and distribute fine water sprays (called aerosols), they process water at elevated temperatures and are often exposed to the atmosphere meaning they can collect organic matter and other debris - an excellent source of nutrients. All these conditions can significantly increase the potential for the growth and proliferation of Legionella bacteria, sometimes across wide areas, and so raise the risks associated with an outbreak of Legionnaires’ disease.
Safety guidance for cooling towers from the HSE
In the UK the Health and Safety Executive has published an Approved Code of Practice known as ACOP L8 – its full title being “Legionnaires disease: the control of legionella bacteria in water”. To support this code of practice they have also published supporting guidance in the form of HSG274 Part 1 which deals specifically with the management of cooling towers.
Both HSE documents provide best practice advice, guidance and support and should be considered essential reading for those with sites that have one or more cooling towers and/or evaporative condensers.
It is vitally important to make sure this type of cooling equipment is properly managed to avoid the risks posed by the growth of legionella and the potential for an outbreak of Legionnaires’ disease. If these risks are not properly controlled or managed, there is a chance the bacteria could swiftly multiply out of control causing serious risks to health and safety.
Where do the potential risks really lie?
This is the most important question to ask. Identifying all possible sources of risk is the first step in considering and controlling those risks and this would normally be done by completing a comprehensive legionella risk assessment of the cooling towers.
The person in charge of this risk assessment process should note all possible sources of risk and take one of two actions:
- Prevent the risk from occurring.
- Control the risk, if it cannot reasonably be prevented.
Why do outbreaks of Legionnaires’ disease occur?
The HSE has found that around 90% of all UK outbreaks of Legionnaires’ disease are caused by one of two things:
- A failure to identify where the specific risks lie.
- A failure to implement solid control plans to combat those risks.
Thus, even if the risks are clearly and correctly identified through a formal legionella risk assessment, it would still be possible for those people with responsibility to ignore those risks, or to fail to put proper plans into place to manage those risks.
Controlling legionella in cooling towers
Once a detailed plan for managing the risks is in place (often called a written scheme of control), it should be acted upon according to the steps indicated in that plan. Regular monitoring of the systems should also be conducted, to ensure the plan is working as it should be, and that the risks are being properly and safely managed.
The need for detailed management records
Proper records should also be kept indicating what was done, when and by whom; how it was done, and what the outcome was. Information relating to each step of the process should also be recorded in a legionella logbook, along with who was responsible for taking each action.
Maintaining records is an essential part of the risk management process as they can be used to demonstrate to the regulator that suitable precautions are in place and active.
The role of the responsible person
A suitably qualified and experienced person – the responsible person - should also be officially appointed to take care of all these elements, or at least ensure that they are completed correctly by suitably competent people or contractors. The responsible person should be someone trained in the management of legionella and in all safety procedures and processes relating to it.
What does legionella training for the responsible person include?
All changes and alterations, either to working processes, or to the way the cooling towers or evaporative condensers are used should also be noted and the plan reviewed to see if any changes are required there. In following these steps, it will be much easier to keep on top of risk management and so improve the health and safety of colleagues and other people.
Registering cooling towers with your local council
And finally… in the UK you have a statutory duty under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992, to notify your local council in writing if you are a business that operates cooling towers or evaporative condensers. The only exceptions to this are when towers or condensers contain no water, or the water or electricity supply is disconnected.
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For further information about our expert cooling tower risk management services please call us on +44 (0) 161 877 0586 to speak to one of our specialists or contact us here.