HVAC Maintenance Obligations

What are the legal implications and corporate responsibility in respect to to HVAC Hygiene Standards?

The Queensland Work Health and Safety Act 2011 defines the duties to ensure the health and safety of workers. This includes the management of risks, the provision and maintenance of safe plant and structures. It sets out that a person conducting a business or undertaking has the responsibility to provide a clean safe work environment. This includes Air Quality, Temperature and any other issue that may affect a workers health or safety.

The responsibilities of a facility manager relating to the ongoing maintenance of a building’s HVAC system are outlined in the applicable Australian standard AS/NZS 3666 (Parts 1, 2, 3 & 4), AS 1668 and AS 1851 which are used as references in this area as well as the AIRAH Best Practice Guideline on HVAC Hygiene.

AS/NZS 3666.2:2011 outlines the scheduling and the details of HVAC cleaning tasks required in order to assist in the control of microorganisms within buildings. The following table is an indicative list of these tasks:
Outdoor air intakes and exhausts MonthlyWhen Necessary
Air filters MonthlyWhen Necessary
Humidifiers MonthlyWhen Necessary
Evaporative air-cooling equipment 3 MonthsWhen Necessary
 Sump3 MonthsWhen Necessary
 Wetted pads3 MonthsWhen Necessary
 Water strainer3 MonthsWhen Necessary
 Air filter3 MonthsWhen Necessary
 Drainage system3 MonthsWhen Necessary
Ducts and components   
 CoilsMonthlyWhen Necessary
 Trays and sumpsMonthlyWhen Necessary
 Condensate drains, tundishes, and trapsMonthlyWhen Necessary
 DuctworkAnnuallyWhen Necessary
 Fans3 MonthsWhen Necessary
 Terminal units inc. coilsAnnuallyWhen Necessary
 Terminal units components including coilsAnnuallyWhen Necessary
 Return air and relief air grillesAnnuallyWhen Necessary
AS/NZS 3666.2:2011 & HVAC Cleaning

The title of this standard is “Air-handling and water systems of buildings – Microbial control Part 2: Operation & maintenance“. As the title indicates, it’s critical that HVAC systems and air-handling systems are maintained in order to control microorganisms accumulating in a building's air system.

As can be seen above, the standard explicitly mentions the following 5 parts of an HVAC system that must be part of a maintenance program:


Frequency  – Monthly

Inspect, clean or replace where necessary.


Frequency  – Monthly

Inspect, clean or replace where necessary.


Frequency  – Monthly

Inspect, clean or replace where necessary.


Frequency  – At least every 3 Months

Inspect, clean or replace where necessary.


Frequency  – Depending on component between 1 Month & 12 months

Inspect, clean or replace where necessary.

Components include:

  • Coils
  • Trays & Sumps
  • Condensate drains, tundishes & traps
  • Ductwork
  • Fans
  • Terminal Units
  • Supply air outlets
  • Return air & relief air grilles

The standard also outlines the need for the existence of Maintenance Manuals and Maintenance Records.

The Maintenance Manual should include details of the maintenance management program including plant servicing, cleaning schedules, and replacement periods for equipment items and components.

Maintenance Records should include:

  1. Date and nature of service performed.
  2. Results of periodic testing.
  3. Details of defects found and remedial procedure undertaken.
  4. The name of the person and company performing the service.

Maintenance manuals and Maintenance Service Records shall be readily available at the site for inspection by regulatory authority upon request.

For the purpose of maintenance management, the maintenance service records shall be retained for a period as required by the regulatory authority.

A Clean-Air, HVAC Hygiene Specialist, can manage all your HVAC maintenance requirements and compile maintenance records which ensures that a building, hospital or factory is compliant.


For Kitchen Exhaust Cleaning, see our AS 1851-2012 Checklist here

For full details of Clean-Air's HVAC Hygiene Operating Standards and Practices, visit our dedicated page here