The regulatory approach to managing cooling water systems in NSW was previously based on a prescriptive approach which required all cooling water systems to be managed according to the same set of minimum criteria. This has been replaced with a performance based (or risk management) approach which requires the individual characteristics and unique risks of each cooling water system to be assessed and controlled.
Building occupiers are required to ensure that there are six key safeguards in place for their cooling water systems:
- Risk assessment of Legionella contamination, documented in a Risk Management Plan (RMP) – every five years (or more frequently if required)
- Independent auditing of compliance with the RMP and Regulation – every year
- Providing certificates of RMP completion and audit completion to the local government authority
- Sampling and testing for Legionella and heterotrophic colony count – every month
- Notifying reportable laboratory test results (Legionella count ≥1000 cfu/mL or heterotrophic colony count ≥5,000,000 cfu/mL) to the local government authority
- Displaying unique identification numbers on all cooling towers.
Although the risk management approach requires cooling water systems to be maintained in accordance with AS/NZS 3666 Part 3 rather than Part 2, other parts of AS/NZS 3666 remain relevant for some aspects of managing cooling water systems.
- Installation, design and commissioning in accordance with AS/NZS 3666 Part 1
- Operation (but not maintenance) in accordance with AS/NZS 3666 Part 2
- Maintenance in accordance with AS/NZS 3666 Part 3.
The requirements for building occupiers to test for Legionella bacteria on a monthly basis and notify high ‘reportable test results’ to the local government authority commenced on 1 January 2018.