Compliance & Standards

AS/NZS 3666.2, explained

The Australian Standard for keeping building air-handling systems clean and microbially safe, and what it means for your HVAC hygiene.

The standard

What is AS/NZS 3666.2?

The AS/NZS 3666 series deals with the air-handling and water systems of buildings and the control of the microorganisms that can grow in them. Part 2 focuses on operation and maintenance: keeping air-handling plant, ductwork, coils, filters and related components clean enough that they do not harbour and spread contaminants such as mould and bacteria through a building.

The standard is published by Standards Australia. It is referenced by state public-health and building-maintenance regimes, and it commonly appears in essential-safety-measure schedules and planned-maintenance programs, particularly in buildings where occupants are more vulnerable, such as aged care and healthcare. How it applies to a specific building varies; your building surveyor or maintenance schedule is the reference point.

Scope

The air side and the water side

Microbial control in buildings has two fronts. The air side covers air-handling units, ductwork, coils, filters and vents. The water side covers cooling towers, warm-water systems and the specialised risk management that goes with them.

Where SAIS fits: we work on the air side, inspecting and cleaning air-handling units, ductwork, coils and vents, and remediating mould contamination, in line with AS/NZS 3666.2. Cooling towers and water-treatment programs sit with specialist water-risk providers; we’ll tell you plainly when something is theirs, not ours.

In practice

What air-side hygiene looks like

  • Inspection first. Air-handling systems vary enormously, so cleaning is inspection-led: we assess the condition of the AHU, duct runs, coils and filters, then scope what actually needs doing rather than working to a one-size interval.
  • Cleaning and remediation. Routine duct cleaning and AC systems cleaning keep the air path clean; where mould or contamination has taken hold, system remediation deals with it and addresses the conditions that allowed it.
  • Documentation. Every job is documented with photo evidence and a detailed report, records that slot into your planned-maintenance file and support your essential-safety-measure reporting.

FAQ

Common questions about AS/NZS 3666.2

What does AS/NZS 3666.2 actually cover?
Part 2 of the AS/NZS 3666 series covers the operation and maintenance of building air-handling and water systems for microbial control: keeping the plant and pathways that move air and water through a building clean enough that they do not become a source of mould or bacterial contamination.
Is AS/NZS 3666.2 mandatory for my building?
It depends on the building and the state. The standard is called up by various public-health and building-maintenance regimes, and it commonly appears in essential-safety-measure schedules and lease obligations, especially for healthcare, aged care and larger commercial buildings. Confirm what applies to your site with your building surveyor or your maintenance schedule.
How often should ducts and air-handling units be cleaned?
There is no single fixed interval: it depends on the system, the environment and what inspections find. The practical approach is regular inspection with cleaning scoped to condition. We assess your air-handling systems and recommend an inspection and cleaning cycle based on what we actually find.
Does SAIS handle cooling towers or water treatment?
No. Cooling towers, warm-water systems and water-risk management are specialist water-treatment work, and we stay in our lane: the air side. If your building needs both, we’re happy to work alongside your water-risk provider so the whole system is covered.
We’ve found mould in the ductwork. What now?
Start with an assessment rather than a quote for a generic clean. Mould in ductwork usually has a cause, moisture, condensation, a failed component, and remediation needs to address both the contamination and the conditions behind it. We inspect, remediate and document the work with photo evidence.

This page is general information about AS/NZS 3666.2, not legal, health or regulatory advice. Obligations vary by state, building class and lease; confirm yours with your building surveyor or facilities compliance adviser.

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