What is AS / NZS 3666 ?
AS / NZS 3666 is the Australian and New Zealand Standard for "Air-handling and water systems of buildings – Microbial control." It's the primary regulatory framework governing how commercial HVAC systems must be designed, installed, operated, and maintained to prevent the growth and spread of microorganisms—particularly Legionella bacteria.
The Standard's Key Components
- Part 1: Design, installation, and commissioning requirements
- Part 2: Operation and maintenance requirements
- Part 3: Performance-based maintenance of cooling water systems
- Part 4: Performance-based maintenance of air-handling systems
Your Legal Obligations Under WHS Law
The Work Health and Safety Act 2011 creates a duty for PCBUs(Persons Conducting a Business or Undertaking) to ensure, so far as is reasonably practicable, the health and safety of workers and others.This includes indoor air quality.
⚖️ Legal Precedent
Facility managers have been prosecuted and fined for Legionella outbreaks linked to poorly maintained cooling towers and HVAC systems.Non - compliance with AS / NZS 3666 is used as evidence of negligence.
AS / NZS 3666.2 Maintenance Requirements
Part 2 of the standard specifies inspection and cleaning frequencies:
Monthly Inspections
- Outdoor air intakes(check for debris, bird nesting)
- Air filters(check loading, replace as needed)
- Humidifiers(check for microbial growth)
- Drain pans(check for standing water, biofilm)
Annual Inspections
- Ductwork(visual inspection for contamination)
- Cooling coils(check for fouling)
- Fan components(check for buildup)
Cleaning When Necessary
The standard requires cleaning "when contamination is observed." This is where professional assessment becomes important—visible contamination often indicates more extensive hidden buildup.
Documentation Requirements
AS / NZS 3666.2 requires that maintenance records be kept for at least three years, including:
- Date and nature of inspections
- Findings and any corrective actions
- Details of cleaning performed
- Filter replacement records
ProSan Australia's AS/NZS 3666 Compliance Program
We offer comprehensive HVAC hygiene services designed around the standard:
- Scheduled inspections with borescope photography
- Duct and coil cleaning using approved methods
- Antimicrobial treatment and mould remediation
- Detailed compliance reports for your records
Ensure your Brisbane facility meets AS / NZS 3666 requirements. Contact ProSan Australia for a compliance assessment.