Cooling water systems must be managed safely in order to prevent the growth and transmission of Legionella bacteria.
Cooling water systems contain one or more cooling towers. These devices are used to circulate cooling water which, in turn, cools the air in refrigeration, air conditioning systems and industrial processes.
A cooling tower reduces the temperature of water through evaporation (evaporative cooling). Cooled water is then piped to an interface with an air-handling system, allowing the water to cool the air. Air ventilation pipes then deliver the cooled air into the building.
Effective management of cooling water systems is essential for protecting public health.
Poorly managed cooling water systems can provide ideal conditions for the growth and transmission of Legionella bacteria.
People can become infected by inhaling fine airborne aerosols generated by cooling towers. Infection may cause Legionnaires’ disease, a serious and potentially life-threatening condition.
The Public Health Regulation 2022 (the Regulation) requires all cooling water systems to be managed according to AS/NZS 3666:3:2011 Air-handling and water systems of buildings - Microbial control - Performance-based maintenance of cooling water systems.
This risk management approach requires the individual characteristics and unique risks of each cooling water system to be assessed and controlled.
The Regulation sets out six key requirements or “safeguards” as part of the risk management approach:
There are several important roles in managing a cooling water system:
The NSW Guidelines for Legionella Control in Cooling Water Systems explain the new requirements in detail.
This series of factsheets summarises the key information for each stakeholder. The full set of factsheets can be found on the NSW Health website.
NSW Health has developed the Legionella Control in Cooling Water Systems training program together with TAFE NSW. All stakeholders are encouraged to complete this training. The course is compulsory for auditors.