Oil Free / Oil-Less Air Compressors

You may have no choice over the quality of the compressed air used in your process – especially in the food and beverage, and, pharmaceutical industries – it just has to be absolutely contaminant free. Oil free compressors are the perfect solution for applications requiring the highest air quality, resulting in oil-less air for your end-product and production processes.

Air purity is critical for many applications where even the smallest drop of oil can cause product spoilage or damage the production equipment, resulting in potential unplanned downtime.

There are many options available to ensure your production runs smoothly and to industrial standards, and Direct Air are happy to advise on what would be the ideal solution for your circumstance.

West Midlands: See our air compressor services in Birmingham, Coventry & West Midlands

South West: See our air compressor services in Bristol, Gloucester, Cheltenham & the South West

ISO 8573-1 Class 0 Compressed Air

Direct Air can advise on the most suitable means to deliver an acceptable level of oil free compressed air from your existing or new system.


Compressed air purity classes for particles

The ISO standard is divided into three main groups of contaminants: Solid particulates, water (both liquid and vapor) and oil (both aerosols and vapor). Each of these categories has up to ten different purity classes (eight for particulates, ten for water and five for oil). The table below displays each ISO class to demonstrate how to choose the correct air purity class and acceptable levels of contamination.

ISO8573-1:2010 CLASS

Solid Particulate Water Oil
Maximum number of particles per m³ Mass Concentration mg/m³ Vapour Pressure Dewpoint Liquid g/m³ Total Oil (aerosol liquid and vapour)
0.1 – 0.5 micron 0.5 – 1 micron 1 – 5 micron mg/m³
0 As specified by the equipment user or supplier and more stingent than Class 1
1 ≤ 20,000 ≤ 400 ≤ 10 ≤ -70℃ 0.01
2 ≤ 400,000 ≤ 6,000 ≤ 100 ≤ -40℃ 0.1
3 ≤ 90,000 ≤ 1,000 ≤ -20℃ 1
4 ≤ 10,000 ≤ +3℃ 5
5 ≤ 100,000 ≤ 7℃
6 ≤ 5 ≤ -10℃
7 5 – 10 ≤ 0.5
8 0.5 – 5
9 5 – 10
X > 10 > 10 10

Oil free compressors

Many manufacturers in critical applications industries choose ISO 8573-1 Class Zero oil-free compressors that provide clean, 100 percent oil-free air. However atmospheric conditions can lead to oil vapour being present in the air generated from an oil free air compressor.

Therefore, additional filtration may be necessary for the system as a whole or point of use depending upon the application.

As with all systems a detailed analysis of the process requirements is the best solution to ensure that the delivered air quality is suitable for the application.

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The future of oil-free compressor design


To deliver oil free compressed air filtration is generally required even in a system that has oil free compressors. Oil free air can also be achieved in systems that have oil lubricated compressors installed.

Depending upon the class of air required Direct Air can advise on how oil free air can be delivered to your system.

Filtration systems including activated carbon filters, activated carbon towers or BEKOKAT catalytic solutions are all possible ways that may be considered to generate oil free air suitable for your process needs.

More info about Air Treatment

Popular Industries

Oil-less compressed air technology is used in many working environments for its reliability and peace of mind. But it’s most essential where quality standards and purity of the production must be to the absolute highest level. Therefore, the air must be completely oil free when involved in applications such as:

Medical and Pharmaceutical

Within the medical and healthcare industries, any compressed air needs to be as clean as possible. Our oil free air compressors meet ISO 13485 standards to ensure the best practice and low maintenance.

Clothing & Fabric

Oil spillages and leaks can lead to damaged goods. Oil free air compressors eliminate this risk and reduce costs while removing unnecessary wastage.


Using oil free air compressors for bodywork leaves a high-quality, smoother finish. Removing the risk of oil contaminating paint.

Food and Beverage

Oil spillages within food production can lead to health risks and product wastage, alongside poor quality products. Oil free air compressors should always be used by any good food and beverage manufacturer to avoid this risk.

Chemical Production

A clean, uncontaminated production line is essential in these environments. Oil free air compressors enhance the purity within chemical production.

Find your oil free solution

Complete the form below to contact the Direct Air team with your enquiry.

Talking to us is easy

We're happy to explain how all our products work and to help you get started over the phone. Real people, plain English and no obligation.

You can call us

0800 021 6800


We offer complete compressed air solutions including design, installation, servicing & WSE inspections.


We consider your entire compressed air system from the compressor to downstream equipment & pipework.

Industry / Sector

Whatever the industry and whatever the application, there's a growing demand for higher-quality compressed air.