Cooling towers and evaporative condensers are among the higher-risk water systems for Legionella, because they spray water into the air and can carry droplets some distance. If your building has one, it needs specialist attention: a clear risk assessment, a written scheme, regular treatment and monitoring, and competent people looking after it. This guide explains why they matter and what good management looks like.
Why cooling towers are different
A cooling tower or evaporative condenser cools water by exposing it to air, and some of it escapes as a fine mist (drift). The water is often kept warm, it circulates continuously, and the packing and basin offer plenty of surface for biofilm. Those are the conditions that allow Legionella to grow and, if drift is not controlled, to be breathed in by people nearby. That is why these systems are treated more seriously than most other water systems in a building. Our guide to biofilm explains part of the picture.
Where you may find them
- On the roofs and in the yards of offices, hospitals, hotels and shopping centres
- With larger air conditioning and refrigeration systems
- At food processing, pharmaceutical and industrial sites
- In data centres and other buildings with heavy cooling loads
Smaller air-handling plant, humidifiers and air conditioning are a separate topic; see our article on air conditioning and humidifiers.
What good management typically includes
- A current risk assessment carried out by a competent person, covering design, location, water treatment, maintenance and who might be exposed.
- A written scheme of control, setting out what is done, how often and by whom. See our guide to the written scheme of control.
- Water treatment to control microbial growth and corrosion, set up and monitored by a competent contractor.
- Regular inspection and cleaning of the basin, packing, drift eliminators and fill, as set out in the scheme.
- Monitoring and sampling as part of the plan, interpreted by someone who understands the results. See how often sampling is typically done.
- A plan for what to do if a result is high, including who is told and when.
- Records. Treatment, inspections, cleaning and results should be kept in a logbook. See our logbook guide.
- Review. After a shutdown, a change in use or any event that may have affected the system, the plan should be looked at again. See our reopening checklist.
Who should do the work
Cooling tower work is specialist. Risk assessment, treatment, cleaning and sampling should be done by competent people who can show their training and experience. For anything beyond a first look, speak to a specialist, and do not assume that general building maintenance covers it. Specific legal and notification requirements for this type of equipment should be checked with the relevant authority, such as the Health and Safety Authority.
Your duties
The Safety, Health and Welfare at Work Act 2005 requires employers and those in control of workplaces to manage risks to people. The HPSC National Guidelines for the Control of Legionellosis in Ireland (2009) are the main Irish reference for controlling Legionella. A building that has a cooling tower or evaporative condenser should make sure it is clearly covered in its Legionella risk assessment and sampling plan.
Talk to Safer Solutions
We carry out fire risk assessments, Legionella risk assessments, Legionella sampling, water tank cleaning and fire extinguisher servicing for businesses across Ireland, including Dublin, Cork, Limerick and Galway. Call 086 275 9728, email info@safersolutions.ie or send us a message and we will be happy to talk it through.