On ISO 16890 standard and selection of air filters

Nigel Hawley, managing director, Camfil Middle East, writes about the new global ISO 16890 standard and selection of air filters.

Nigel Hawley, Camfil Middle East, ISO 16890, ISO certification

Isn’t clean air a human right? We at Camfil believe so. Air is invisible; however, it is an indispensable part of our life. On average, we breathe 15kg of air per day and each breath contains millions of harmful particles. Indoor air is often even more polluted than external air.  Should we compromise the quality of air we breathe, or shall we take an action to enhance it? At Camfil, we believe so and we have been promoting this message for the last 55 years, and encouraging people to engage with this global issue.

No doubt, rapid industrial development during the last two decades of the 20th century has detrimentally impacted both indoor and outdoor air quality. Globally, air quality is deteriorating day by day and the Middle East region is no exception. The air we breathe is becoming more polluted with particulate matter (PM) every day. PM is commonly defined in terms of physical size and is expressed in microns, most commonly PM1, PM2.5 and PM10. Most countries are still focusing on PM2.5 concentration in ambient air conditions. However, latest research results show that PM1 has the closest relationship with human health and poses the most serious hazards to human health. These tiny particles penetrate the bloodstream and cause harmful effects to our respiratory and cardiovascular system.


Existing standards EN779:2012 and ASHRAE 52.2, used widely in this region, have limited effectiveness in terms of benefitting air quality in real-world conditions. Both standards used different testing approaches which hampered the possibility of comparing results. The new global standard ISO 16890 has finally introduced a standard to test all air filters in a wide variety of environments. The new filter classification system provides clear information on the effectiveness of a specific filter to remove different sized harmful particles from the air.

EN779:2012 will be withdrawn at the end of June 2018 and will be fully replaced by ISO 16890.

There are five different aspects to the new ISO 16890 standard:

1. Efficiency and pressure drop measurement

The efficiency test is wider than that currently used under EN779:2012 and AHSRAE 52.2, covering a range of particles from 0.3 µm to 10 µm, whereas previously, the testing only covered a range of 0.3 µm to 3 µm particles. The removal efficiency in existing standards was also calculated solely on one particle size (0.4 µm) whereas the new ISO16890 focuses on various particles sizes from 0.3µ to 10µ. These changes will lead to a more accurate classification of air filters in terms of particulate sizes and their impact on the indoor environment.

2. Discharging conditioning

Discharging conditions also vary from EN779:2012 and ASHRAE 52.2. For filter discharge efficiency testing under ISO 16890, the isopropanol method has been chosen due to its good discharging properties. However, the method has been further developed and is no longer based on saturated gas-phase discharging. Although the new testing method is slower and more complicated to conduct in the laboratory than the previous wet process, it discharges the filter 100% without affecting the fiber structure of the filter leading to more accurate test results.

3. Post-discharging efficiency measurement

This measurement evaluates the functionality of air filters after they have been used. The efficiency of post discharged filters must be similar to their initial classification of efficiency to gain the respective classification rating.  In other words, an ePM1 filter with 60% efficiency against PM1, must attain this 60% efficiency rating both before and after discharge.  This is very important as this most closely simulates normal working conditions.

4. Dust holding and arrestance measurements

Compared to ASHRAE52.2 and EN779:2012, the test dust in ISO 16890 has been changed to a finer test dust designated as L2 under ISO 15957. This finer dust takes a longer time to load in the laboratory, but it better stimulates real-life conditions.

5. Calculation and ePM classification

The major differences between previous standards and ISO 16890 become apparent in the final classification and calculation step. Through calculation, the measured test results are converted and related to the known outdoor air pollution measurements PM1, PM2.5 and PM10.

Based on the test steps, air filters will be categorised into four groups:

The next important step is to select an air filter based on these classifications within ISO 16890. To aid the selection of an appropriate air filter which will help ensure the required indoor environment, European Union States have adopted Eurovent 4/23. This standard classifies Ambient Air Quality based on WHO guidelines and suggests how to select the correct air filter to achieve the targeted indoor environment.

As per WHO [2005] guidelines, the PM levels considered are as follows:

PM2.5  ≤ 10 µg/m3 annual mean

PM10 ≤ 20 µg/m3 annual mean

According to EN 4/23, Ambient Air is classified into three groups:

ODA 1 – Outdoor Air temporarily dusty and applies where WHO guidelines fulfilled [PM2.5  ≤ 10 µg/m3; PM10 ≤ 20 µg/m3]

ODA 2 – Outdoor Air with high concentration of particulate matters where WHO guidelines exceeded up to 1,5 annually [PM2.5 ≤ 15 µg/m3, PM10 ≤ 30 µg/m3]

ODA 3 – Outdoor Air with very high concentration of particulate matters where WHO guidelines exceeded up to 1,5 annual means [PM2.5 ≤ 15 µg/m3, PM10 > 30 µg/m3]

Based on the outdoor air classification, supply air to the indoor environment has been classified into the following five categories:

These two classifications support the selection of filters to ensure supplied air is as per the WHO standard and the below table provides for the optional selection of the filters based on these requirements.

* Minimum filtration requirements ISO ePM1 50% refer to a final filter stage
** Minimum filtration requirements ISO ePM2.5 50% refer to a final filter stage
Presented efficiency values concern both single filter and multi-stage filtration systems with a cumulated efficiency.

Filter selection remains a decision dependent upon the quality of indoor air quality one wishes to achieve. For example, when selecting air filters for an office building in the Middle East region, where let’s say the sandy conditions result in the outdoor air being classified as ODA2 and the supply air to the room is SUP1 then one must select air filters with a minimum efficiency of ePM1 80% to achieve the quality of indoor air that is required.  Similar methodology should be followed for selecting filters for each type of indoor environment like healthcare facilities, public and private buildings etc., where the quality of indoor air required may vary. Hence, the choice of filters to achieve the indoor air quality required relies on well trained and educated personnel who should select air filters according to the new ISO 16890 standard and ensure the supplied filters have achieved the requisite ISO standard, which unfortunately is not so today for all the filters being manufactured and used within the region.

In summary, the key benefits of ISO 16890 include:

  • An acknowledgement that air filters positively influence indoor air quality and benefit human health;
  • Global applicability; we now have one test and classification system that can be utilised throughout the air filtration industry that can be readily understood by specifiers, purchasers and users of air filters; and
  • The ability to easily select and comprehend product value in relation to function and application.

In short, the ambient environment, and poor indoor air quality, should never be allowed to affect the short or long-term health of individuals.  Stakeholders should always seek to understand the benefits of protecting people’s health, business processes, machinery and the environment itself. Adopting and applying ISO 16890 in the region will be challenging but early adoption of this standard is of paramount importance and is already being seen. Attention is slowly moving away from solely considering the initial cost of a filter. The health considerations of each of us who spend almost 90% of our time indoors needs to be foremost in people’s mind when selecting filters. We, at Camfil, believe that every human being has a right to clean air and we are ready to help provide a better future for all those who feel the same way.

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