How to Control Legionella in Evaporative Cooling Systems

How to Control Legionella in Evaporative Cooling Systems

In this article the water safety specialists at Legionella Control International look at the control of legionella in evaporative cooling systems and similar water based cooling towers.

Using inspection data taken from the one of the UK’s primary health protection agencies our experts review the report’s findings to discover that nearly one third of all sites inspected were found to be non-compliant on health and safety grounds, with a number of recurring themes evident.

Controlling legionella in evaporative cooling systems

While any hot or cold water system can be prone to an increase in Legionella bacteria given the right conditions, evaporative cooling towers and similar wet systems may pose a particular risk as they have the potential to spread water as a fine spray over large areas – up to 6km.

Cooling towers and evaporative condensers

Evaporative cooling towers may allow legionella contaminated water droplets to disperse as an aerosol in to the air and so potentially affect people working at a tower, nearby or over wider distances. Evaporative condensers also pose a potential risk, as they use a heat exchanger to cool water, rather than allowing direct contact with air.

Cooling tower registration

All businesses with evaporative cooling systems must register with their local council to remain within the law. This highlights their presence and allows for periodic inspections by the local regulator to be made. Such inspections can occasionally highlight issues with cooling towers and similar higher risk systems. In some cases, those issues could be potentially hazardous to health and would require urgent attention.

Inspections revealed breaches at 625 sites over a 17-month period

Official data available on the Health Protection Scotland website indicates 1,906 premises were inspected from 1st April 2013 through to the end of August the following year. During that time, 625 sites exhibited issues relating to a lack of compliance with health and safety rules. This amounts to a third of all sites.

What caused the breaches and how can future ones be avoided?

While individual sites may have exhibited their own issues, most problems fell into four general areas which were as follows:

  • Lack of staff training
  • Poor or inadequate maintenance
  • Poor or no legionella risk assessment present
  • Poor or inadequate management scheme to control legionella

A lack of training in how to maintain and manage the water systems was found to be a clear issue in many cases. In others, insufficient maintenance was a major cause of problems. Poor maintenance makes it easier for Legionella bacteria and other bacteria to grow and multiply, both in cooling towers and in the water inside the systems.

In some cases, a legionella risk assessment had either not been done at all or had been insufficient for the situation in hand. Furthermore, while every site should have an in-depth control scheme written down, some sites failed to meet this requirement or did not have a sufficiently detailed one to adhere to.

Focusing on the areas of concern to reduce risk

Focusing on these four elements of training, good maintenance, risk assessment and management helps to ensure a responsible and balanced approach to the risks inherent in evaporative cooling systems.

The conditions within such wet cooling systems can be ideal for the growth and spread of Legionella bacteria over wider areas. By covering all legionella risks in a competent assessment and allowing the correct controls and measures to be written down and then implemented and managed, there is far less chance of a potentially dangerous situation occurring. There is plenty of free guidance online via Legionella Control International or the Health & Safety Executives website for those wanting to learn more about the control of legionella in evaporative cooling systems.

Legionella control water safety specialists

Our teams of water safety specialists support those responsible for the control of waterborne pathogens including Legionella bacteria, helping them to protect public health and meet their health and safety obligations in this area. We deliver professional water safety risk assessments for legionella and other waterborne pathogens, water testing, independent compliance auditing, City & Guilds training and other environmental risk management services that help keep staff and others safe.

If you have questions about any of the issues raised above or you would like to speak with one of our specialists please call us today on 0330 223 36 87 or contact us here.