Klase ISO standarda za kvalitet komprimovanog vazduha

Prvo, većina sistema komprimovanog vazduha ima jedan ili više filtera. To je zato što vazduh koji napušta kompresor može da sadrži razne zagađivače kao što su: pesak, so, šećer, rđa, cement ili veštačke boje, bakterije i viruse. Ova mešavina može da kompromituje vaš krajnji proizvod. Zato su filteri toliko važne komponente za vaš sistem vazduha kako bi se obezbedio kvalitet i pouzdanost proizvodnje. Ali koliko treba da bude čist komprimovani vazduh i kakvi vam filteri za to trebaju?

For those unfamiliar with compressed air systems, choosing the right air purity level can seem complicated. Different industries demand different standards, and contaminants like moisture, dust, and oil each affect performance in their own way. To make things comparable worldwide, the ISO 8573 series of standards was created.

First published in 1991 and revised in 2010, ISO 8573-1:2010 sets the rules for compressed air purity. The update refined the classification system and testing methods to match modern industry needs, ensuring that air quality can be measured consistently everywhere.

The series is made up of nine parts. ISO 8573-1 defines the purity classes, while the other parts cover testing methods for oil, water, particles, gases, and even microorganisms. Together they provide a complete framework for assessing compressed air quality.

Within ISO 8573-1, air purity is classified by three groups of contaminants: solid particles, water, and oil. Each group has several classes, with lower numbers meaning cleaner air. For instance, class 1 particle limits are extremely strict, while class 9 water levels permit up to 10 g/m³. Oil ranges from just 0.01 mg/m³ in class 1 to 5 mg/m³ in class 4.

This system helps companies select the right filtration and drying equipment for their needs. It avoids unnecessary costs while guaranteeing compliance, process safety, and long-term reliability.

By knowing how each ISO class is defined, you can select the right filtration level for your system, avoiding unnecessary costs and ensuring consistent air purity. See the table below for a quick overview of purity classes.

Note:
While the ISO 8573-1 standard defines several purity classes, Class 0 deserves special mention. In Atlas Copco terminology, Class 0 always refers to air produced by an oil-free compressor, not to achieving lower oil content through additional filtration stages. This distinction ensures true oil-free air at the source, reducing maintenance needs and the risk of contamination in sensitive applications.

ISO 8573-1 defines particle classes (P) based on the number and size of solid contaminants in a cubic meter of compressed air. These particles can include dust, rust, pollen, or wear debris from pipes.

• Class 1: Very high purity, maximum particle size ≤ 0.1 μm and extremely low particle count. Used in critical environments such as semiconductor manufacturing, pharmaceutical production, and medical applications where even microscopic particles can cause defects or contamination.

• Class 2–3: Moderate filtration, particle size up to 1 μm (Class 2) or 5 μm (Class 3). Common in food & beverage, chemical processing, and precision engineering where clean air prevents product contamination and equipment wear. 

• Class 4–6: Minimal or no filtration, particle size up to 15 μm (Class 4), 40 μm (Class 5), or higher. Typically means no filter is installed, which is not recommended for pneumatic tools or any sensitive equipment, as particles can cause abrasion and premature failure.

The water classes (W) are determined by the moisture level in compressed air, measured through pressure dew point or, in higher classes, by liquid water content.

• Class 1: Pressure dew point ≤ −70 °C. Used in ultra-critical environments such as semiconductor manufacturing, pharmaceutical production, and high-precision electronics where even trace moisture can cause defects.

• Class 2–3: Pressure dew point between −40 °C and −20 °C. Common in food & beverage processing, chemical plants, and medical applications where low moisture prevents contamination and corrosion.

• Class 4–5: Pressure dew point between +3 °C and +7 °C. Typical for general industrial use, such as automotive, metal fabrication, and packaging, where moderate dryness is sufficient to protect tools and equipment.

Oil classes (O) include both aerosol and vapor forms of oil that can enter the system from lubricated compressors or the surrounding environment.

• Class 0: Achieve the highest possible purity, 100% oil-free, in accordance with Atlas Copco standards. Essential for industries with the most stringent purity requirements.

• Class 1: Allows a maximum of 0.01 mg/m³, required in industries like food, beverage, or healthcare.

• Class 2-3: Up to 0.1 mg/m³, often used in general industrial processes.

• Class 4-5: Up to 1 mg/m³ and 5 mg/m³ respectively, sufficient for less demanding pneumatic applications.

When defining the required compressed air quality, it is important to specify it according to ISO 8573-1:2010. The standard uses a three-part code that indicates the chosen purity class for particles (P), water (W), and oil (O). For example, an air quality requirement of 2.4.1 means Class 2 for particles, Class 4 for water, and Class 1 for oil. This format avoids misunderstandings between suppliers, operators, and inspectors by making the requirement both simple and precise.

Specifying compressed air quality starts with understanding the application. Industries such as pharmaceuticals, food, and electronics often require stricter classes, while general manufacturing or workshop tools can work with mid-range classes. It is also important to balance purity with cost: producing very clean air requires additional filtration, drying, and energy consumption. Defining only the level of purity that is truly needed helps ensure compliance, process safety, and energy efficiency.

Postoje dva glavna razloga zbog kojih korisnici komprimovanog vazduha treba uvek da razmisle o neophodnim nivoima čistoće komprimovanog vazduha.

• Neke primene zahtevaju da ostvarite određene standarde kvaliteta. Ukoliko ne dostignete taj standard, može doći do ogromnih problema u proizvodnji.
• Kao načelno pravilo, što  vazduh mora da bude čistiji, skuplji je za proizvodnju. Ekstremno čist vazduh zahteva dodatnu opremu, kao što su filteri i sušači, kao i dosta energije koja se troši u procesu proizvodnje. Zato, određivanje pravog kvaliteta vazduha može da bude veoma značajno za smanjenje troškova i zaštitu okoline.

Što je niži broj kojim se označava kategorija, vazduh će biti čistiji. To znači, na primer, da vazduh klase 4 može da sadrži više nečistoća nego vazduh klase 3.

U slučaju čvrstih čestica, standard definiše koliko čestica može da se sadrži u vazduhu po m³. Dalje se ova sekcija deli prema veličinama čestica. Na primer, vazduh klase 1 može da sadrži 20,000 čestica veličine 0.1-0.5 mikrona, manje od 400 čestica veličine od 0.5-1 mikrona i manje od 10  čestica veličine od 1-5 mikrona. Vazduh klase 2 zahteva da vazduh sadrži manje od 400,000 čestica veličine 0.1-0.5 mikrona, manje od 6,000 čestica veličine 0.5-1 micron i manje od 100 čestica veličine 1-5 mikrona.

U slučaju vode, klase su oštrije i rangiraju se prema tački rosišta,  počevši sa klasom 7 i određuju se prema sadržaju tečnosti u vazduhu u gramu po kubnom metru.

Za kraj, ISO klase za ulje se određuje prema sadržaju ulja u mg/m³. 

Once you know the required compressed air ISO class, the next step is choosing the right air treatment equipment. Filters and dryers work together to remove all main contaminants: particles, water, and oil, ensuring the air quality matches your ISO 8573-1 specification.

• Particulate filters remove dust, rust, and other solids, helping achieve the correct particle (P) class.

• Coalescing filters capture oil and water aerosols as well as fine particles, ensuring both oil (O) and particle classes are met.

• Activated carbon filters eliminate oil vapor, odors, and hydrocarbons, required when very pure air is needed, such as in food or pharmaceutical production.

• Dryers reduce the moisture content (W class) by lowering the pressure dew point.

  • Refrigerant dryers are ideal for general industrial use.

  • Desiccant dryers provide extremely dry air for sensitive or low-temperature environments.

When designing your system, always match filters and dryers to your target ISO 8573-1 code.
This ensures compliance, protects your equipment, and avoids unnecessary energy and maintenance costs.

Za osobu bez iskustva, izbor pravog kvaliteta vazduha izgleda kao neverovatno težak zadatak. Ali, postoji alat koji može da učini ovaj izbor daleko lakšim, i zove se ISO 8573-1:2010.

To je tehnički naziv internacionalno prihvaćenog standarda za klase čistoće komprimovanog vazduha. Ovaj standard se definiše kroz rangiranje klasa u kojima je dozvoljeno određeno prisustvo zagađivača (kao što su: vlaga, čestice, ulje i druge zagađujuće supstance – u komprimovanom vazduhu).

Dok ISO standardi pojednostavljuju stvari, postoje mnogi drugi zagađivači i klase čistoće čije razumevanje može biti teško.

ISO standardom su zagađivači podeljeni u tri grupe: čvrste čestice, voda (u obliku pare i u tečnom stanju) i ulje (u vidu pare i aerosola). Svaka od ovih kategorija ima do deset različitih klasa čistoće.

Ukoliko vam je potrebna pomoć da sastavite sistem za vazduh koji će biti u skladu s vašim potrebama, kontaktirajte Atlas Copco stručnjake koji su uvek spremni da vam pomognu.

Note:
ISO 8573-1 purity is expressed as [Particles : Water : Oil].

Unsure which ISO class your compressed air system currently meets or should target? Poor air quality can damage equipment, compromise products, and increase operational costs.

This article was updated in October 2025; it was originally published in June 2021.