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DIN EN ISO 16890: The new standard for classifying air filters

EN 779 has been the most widely-used method of classifying air filters for over 20 years. But from the beginning of 2017, a new standard came into force that completely changed the way that filters are tested and categorized.

The good news is that ISO 16890 brings a number of benefits over the previous standard. It uses a number of new approaches and mechanisms that make the testing process more indicative  of  the  conditions  that  the  filter  will  operate  within  once  installed. And the new rating system centers on the ultimate aim of an air filter - removing particulate matter - so it’s easier to find a product that’s matched to your needs.

ISO 16890 - easy explanation

Our new video explains why ISO 16890 was introduced, why it’s important, and how it categorises filters according to their performance in the real world.

Key facts on DIN EN ISO 16890

ISO 16890 provides a standardized process for classifying air filters used in general ventilation - in other words, it's a new method for grouping HVAC filters depending on their performance.

EN 779 has done much to improve quality standards across the industry and has provided a uniform method for selecting filters. But our understanding of the air around us has grown enormously over the 20 years since its launch, and its limitations are now obvious.

Chief among these limitations is the fact that EN 779 only tests a filter's performance against one particle size - 0.4 µm. Particulate matter (PM) is not uniform in size or shape, so exposing a filter to one particle size in testing is not reflective of the conditions it will face when in operation.

The new ISO 16890 standard differs because it focuses on a filter's ability to capture different size particles in the danger zone - where particulate is too small for our bodies in-built defences to protect against.

Testing under ISO 16890 exposes a filter to particles from 0.3 µm all the way up to 10 µm. This means that filters are tested in conditions that are much more similar to real life, and you get a product capable of performing as you expect it to.

Based on this testing, filters are classified according to their efficiency at PM10, PM2.5 and PM1 - that is, particulate matter with a diameter less than 10 µm, 2.5 µm and 1 µm respectively.

And these particle sizes are the basis for the four ISO 16890 groups: ePM1, ePM2.5, ePM10 and Coarse. ‘e' in the group name simply stands for efficiency and the number relates to PM size. To qualify in each group, a filter must have 50% efficiency at that PM size. So, a filter classified as ePM1 captured at least half of the PM1 contaminant it was subjected to in testing. Filters achieving an efficiency lower than 50% with PM10 go into the Coarse group.

ISO 16890 Filter Group
< 50% of PM10
ePM10≥ 50% of PM10
ePM2.5≥ 50% of PM2.5
ePM1≥ 50% of PM1

Once tested, filters are awarded an efficiency rating that's rounded to the nearest 5%. So you will see filters described as ePM10 70% and ePM2.5 95%, for example. This simply means that the first filter is 70% efficient at PM10 and the second product is 95% efficient at PM2.5.

ISO 16890 was launched at the beginning of 2017, but most countries have an 18-month transition period where EN 779 will continue to be valid alongside the new standard. This is to give end users, distributors and manufacturers time to adjust to the new system.

Once any transition periods are finished, no. ISO 16890 uses a different grouping method to the G and F classes that we're familiar with under EN 779. A direct comparison between the old filter classes and the new groups is not straightforward as EN 779 examines a fraction of the performance data that ISO 16890 does. Making like-for-like conversions also ignores much of the benefits that ISO 16890 brings.

No, not quite. ISO 16890 is just for general ventilation applications, so the higher efficiency filters classified according to EN 1822 - such as EPA, HEPA and ULPA filters - are not affected by the new standard.

ISO 16890 also only currently impacts those countries adopting the EN 779 standard, so regions using other schemes - such as ASHRAE - will also remain unchanged for the time being. Discussions to introduce ISO 16890 to these markets are underway, with the aim of creating a truly global standard.

Guide to ISO 16890

Take an in-depth at the new ISO filtration standard.


Ready for ISO 16890

Testing times

Testing an air filter according to ISO 16890 is a much more extensive process than the EN 779 standard being replaced. EN 779 challenged a filter with just one particle size-0.4 µm, which made the process straightforward, but didn't reflect what happens outside of the laboratory, in real life. Under ISO 16890, filters are tested against 12 different particle size groups from 0.3 µm up to 10 µm.

Testing a filter is done by challenging it with a test aerosol and comparing the number of particles going in against the number of particles that get past the filter on the clean air side. As ISO 16890 introduces a wider range of particle sizes, testing is no longer just a case of counting upstream versus downstream. Now, test rigs need to sort and analyse different sized particulate across 12 channels. This means that although the test is much more realistic, it does require the latest sophisticated equipment.

The added benefit of this is that the new equipment is much more accurate than the previous EN 779 test rigs. So it gives us a much clearer picture of a filter's performance too.

We are ready

We have just completed the fit out of our Swedish research facility with an all new laboratory that's ready for ISO 16890. It's a 240 m² space with full air-conditioning control for temperature and humidity to create the perfect test environment. Contained within the laboratory is a brand new ISO 16890 test rig capable of carrying out the more demanding tests of the new standard. And alongside this, sits a raft of other testing equipment including a burst pressure test rig for pushing our products to the limit (and beyond).

Later this year, this new equipment will be joined by an oil mist rig for the testing of oil mist eliminators used in metalworking. And a water separation machine to test the performance of our range of marine weather louvers will be installed in 2017.

The aim of all this investment is to analyse the performance of our products in as realistic an environment as possible. That way, we can ensure that our products are ready for use in your air handling unit.