PARTICLES AND RELATIVE MICRON SIZE
Particles are generated or become airborne through everyday human, commercial, and industrial activity, making filter efficiency a critical factor in maintaining clean and safe air. In the post-pandemic environment, this concern has grown significantly as individuals seek to protect themselves at home, at work, and within the broader community.
Airborne particles are typically measured in microns (millionths of a meter) and vary in size depending on their source. A strand of human hair—ranging between 50 and 150 microns—offers a useful comparison when considering the relative size of large and small airborne particles.
Why be concerned about the size of the above particles?
| Common Particles | Size |
|---|---|
| Human Hair | 50-150 microns |
| Household dust and lint | 0.01-100 microns |
| Pollen | 10-110 microns |
| Mould | 1-50 microns |
| Pet dander | 0.1-10 microns |
| Tobacco Smoke or Soot | 0.01-1 micron |
| Viruses and Bacteria | 0.001-10 microns |
FILTER RATING
A filter’s efficiency rating describes the relationship between particles retained or trapped by the filter to the number of particles entering the filter.
For example if you are looking at the table below, it shows the rating and the efficiencies of each filter. If you look at H13 (Merv 17), it shows the filter is a 99.95% efficient filter. This indicates that 99.95% of particles entering the filter are removed from the air by the filter.
HEPA filters, as used in cleanroom environments and biological safety cabinets, are designed to capture at least 99.97% of particles ≥0.3 microns. Equipment such as the UltraSafe Class II Biological Safety Cabinet relies on this level of filtration to ensure a sterile workspace and protect both the operator and the product.
FILTER EFFICIENCY TABLE
Download the filter efficiency guide HERE
Introducing AS 16890
AS 16890 is Australia’s adaptation of the ISO 16890 air filter standard. It classifies filters based on their efficiency at capturing PM1, PM2.5 and PM10 particles, aligning with public health and environmental metrics.
Unlike the global version, ISO 16890, the Australian adaptation mandates that test results come from ILAC-accredited labs (like NATA), ensuring verified, transparent performance data. For schools, hospitals, and commercial HVAC systems, it’s a reliable way to compare filter effectiveness using recognised test methods — with results you can trust.
Why AS 1324 Still Matters and Where ISO/AS 16890 Falls Short
While AS 16890 brings meaningful improvements to air filter classification by focusing on PM efficiency and accredited test results, it does not address construction safety, long-term durability, or mechanical performance. These are critical elements in many Australian HVAC and clean air applications.
AS 1324, Australia’s long-standing standard for air filter construction, remains essential for several reasons:
Construction & Safety Requirements
AS 16890 (and ISO 16890) provide a test method but not a construction standard. AS 1324 includes specifications for:
- Filter integrity and burst strength
- Resistance to fibre shedding
- Washable and renewable media
- Fire performance
- Long-term mechanical reliability
Whole-of-System Compatibility
Filters installed in healthcare, education, and industrial environments must withstand variable airflow, humidity, and vibration. AS 1324 ensures filters are built for operational resilience, not just lab test compliance.
Risk Management & Regulatory Compliance
AS 1324’s construction requirements help protect against system failures, airborne contamination, and non-compliant installations — particularly in risk-critical sectors like healthcare and defence.
While AS 16890 verifies how a filter performs in a lab, AS 1324 ensures the filter is built to withstand the realities of Australian HVAC systems. Together, they provide the confidence that filters are not only effective but truly fit for purpose.
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