HVAC Hygiene Best Practice Guideline

HVAC Hygiene Best Practice Guideline

Specialised HVAC cleaning services have been available in New Zealand since the early 1980s. However, it was not until the 1990s that growing public concern for better indoor air quality (IAQ), improved indoor environment quality (IEQ) and improved ventilation hygiene that the cleaning of HVAC systems became a widely adopted practice. General awareness of occupational, public health and comfort issues associated with HVAC systems continues to increase and system owners and managers have responded with better management of these systems.

More recently, building energy use and energy conservation has become increasingly important to building owners and system operators, including the need to operate HVAC systems at their maximum efficiency. Maintaining HVAC systems in a clean condition is one essential and fundamental way of achieving these objectives.

Although Australian and New Zealand Standards, such as AS1851, AS/NZS 3666.2, and industry maintenance specifications, such as AIRAH DA19, specify requirements for HVAC system and component inspection and cleaning, very little criteria for evaluating and assessing different types and levels of contamination are provided.

The Guideline establishes the criteria for evaluating the internal cleanliness of HVAC system components and clearly determines when cleaning is required, according to the building use. The Guideline describes the components of HVAC systems to be evaluated, the types of contamination likely to be encountered and includes for post fire and flood damage assessments.

Minimum inspection frequencies for various HVAC systems and components are specified for scheduled maintenance programs.

The Guideline also provides test methods that can be used to verify that a clean system hygiene level has been achieved following a system cleaning or restoration project. This document also includes recommendations for creating new access openings within HVAC systems where they are required to facilitate the inspection and cleaning of the internal surfaces of system ductwork and components.

The Guideline does not provide instructions on how to clean or restore HVAC systems but does provide some guidance on the management of cleaning and restoration projects.

This edition of the Guideline was developed by the AIRAH HVAC Hygiene Special Technical Group and modified by IRHACE for New Zealand conditions and building code requirements. This was reviewed by Industry prior to publication.

Read the full article in the Industry Journal, December 2022 issue