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World-class industrial air purifier filters

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Zehnder’s industrial air filters capture pollution particles of every shape and size. Our unique approach means we have an air filter solution for businesses of all sizes and from any sector.

What are industrial air purifier filters?

Air purifier filters are at the heart of every industrial air cleaner and are largely responsible for removing dirt particles such as dust, gases, vapours, smoke, and microorganisms from the air in your building. But not all filters are the same. 

There are a variety of different filters that are highly effective, depending on the environment, the industry, and the amount of particles in the air. To choose the right filters for your needs, it is therefore very important to understand the particles you are dealing with. So that your air purifiers are equipped with the ideal mixture of dust absorption capacity and permeability. 

What types of filters are there and how do they differ from each other?

Zehnder’s air cleaning solutions offer many different kinds of filter configurations, tailored to fit specific environments. The most important are flimmer filters (a Zehnder inhouse development), pocket filters, and compact or HEPA filters.  

Flimmer filters:

Flimmer filters are made from thousands of polypropylene fibers that electrostatically trap particles. Compared to other filters, flimmer filters allow a high air flow rate – even if they contain a lot of dust. They can be used alone or in combination with a pocket or compact filter.  

Patented Bonus: When flimmer filters are used as a pre-filter for a compact or pocket filter, you can significantly extend the life of the secondary filter! This extra is only available from us and is patented as FlimmerM®. 

air purification system filter flimmer
air purification system filter bag

Pocket filters:

Pocket filters (also known as bag filters) have it all – because they deal with very high levels of dust.

They are called pocket filters because the filter is made up of several adjacent pockets. The air, including disruptive particles, is drawn into these pockets, and released again on the other side, cleaned.

Pocket filters can be used individually or in combination with other filters (as pre-filters or downstream filters).

Compact filter and HEPA filters:

Compact filters come in many different filter classes, ranging from coarse filters for trapping larger, coarse particles, to what’s known as HEPA filters for harmful ultrafine particles, whether chemical, biological, or even radioactive.

They work as supportive filters and can be obtained in different filter classes (up to HEPA 14).

air purification system filter compact

However, in many cases we recommend multi-stage filter systems.

This is because multi-stage filter solutions are more effective in terms of the amount and type of particles they can remove, have a longer service life, are adaptable, energy efficient, and can handle higher air flow rates. 

industrial air filter flimmer m working principle

How do air purifier filters work?

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The particle sizes set the tone: Filter classes and what you need to know

Filter Classes – another word that can cause confusion. But don't worry, we'll bring some light into the darkness. 

Firstly, there are different filter classes that have been defined and standardised by different organisations, for example the EN or ISO classifications. These classes indicate how efficiently various filters remove harmful particles of all sizes from the air in the room. The higher the filter class, the more effective the filter is at removing particles from the air.

The most important distinguishing feature is always the size of the particles to be filtered. This is given in PM (particulate matter). For example, an ISO ePM10 80 % class filter can filter 80 % of all PM10 particles. 

  • PM1: Particles smaller than 0,001 mm
  • PM2,5: Particles between 0,001 mm and 0,0025 mm
  • PM10: Particles between 0,0025 mm and 0,01 mm
  • Coarse dust: Particles equal to or larger than 0.01 mm
industrial air fitlers particle sizes compared

The different standards for air purifier filters

ISO 16890 and ASHRAE 52.2 

This is the internationally recognised classification and testing standard for air filters. It replaces the previous EN779:2012 standard. To comply with the ISO 16890 standard, an air purifier filter must be able to filter at least 50% of the particles from a certain fine dust category (PM). The ASHRAE 52.2 standard is primarily used in the United States


EN1822 defines the filter classes for very fine filters (particles ≤ PM1). It is the valid standard for the certification of EPA, HEPA, and ULPA filters in Europe and the USA. 

clean air references full

So, which air purifier filter is the right one for your company?

Each type of filter has its own advantages, depending on the environment and the particles to be filtered. 

This means, making the right choice is easier said than done. That’s why our experts are here to advise you right from the start and determine the best filter combination for you. Making sure you get the air quality that you want.  

If your business cares about clean air, get in touch with us today to find out how we can improve the air quality at your site!

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