The Difference Between Oil-free Compressors and Class 0 Oil-free Air Compressors

Monday, October 28, 2019

Some compressor brands offer air compressors described as "oil-free", “oil-less", or “technically oil-free”. These terms are misleading.


They are often confused with air compressors which provide class 0 oil-free air. At BOGE Australia, we believe passionately that our potential and existing customers should be given all salient information so that they can make the best purchasing decision for their needs. With this in mind, and if you are looking to buy an oil-free air compressor in Australia, let us now explore the difference between oil-free compressors and oil-free class 0 air compressors.


What Does Oil-Free Compressed Air Mean?

Each region has its own legislation and regulations to ensure that produced compressed air is standardised for specific uses, though ISO numbers are the preferred means (more on that below). Unfortunately, due to the non-standard use of terms, however, like oil-less air compressors and technically oil-free air compressors, there is some confusion about what each means. They may sound similar, but they can differ drastically in reality.


In order to avoid this confusion, let us clearly define what each term means in practice:


Technically Oil-Free Air: If you see an air compressor marketed as "technically oil-free", what this actually means is that oil as indeed present somewhere. The oil is used to lubricate moving parts within the compressor. This is often seen with piston compressors. Oil filtration is then added to the air compressor. This, in theory, removes oil particles from the produced air. However, unless you are using cutting-edge filtration technology, there is always the risk that oil will end up in the air outlet. Some companies will market their air compressors as "technically oil-free", because these compressors tend to be cheaper to produce than class 0 compliant air-compressors.


Class 0 Air: Unlike "technically oil-free air", class 0 compliant air provides certainty that the compressed air is 100% oil-free. Most of the time, this is achieved by completely removing oil from the environment. This is done, not through filtration, but instead by using synthetic materials such as Teflon in manufacturing the moving parts of the compressor. These alternatives to oil provide excellent lubrication for moving parts and give complete confidence to users that there is no oil present.


The Difference Between ISO Class 1 and Class 0

How can you be certain that your compressor will produce completely clean, oil-free air? First, by purchasing your compressor from a reliable manufacturer. We at BOGE, for example, have been designing and engineering industry leading air compressors and accessories for well over a hundred years. On top of doing business with a reliable company, looking for the ISO numbers associated with a compressor will also alert you to the compressor's properties.


ISO stands for International Organization for Standardization. It is a way for commercial, private, mining, manufacturing, medical, and industrial sectors to agree upon set air compression standards. ISO numbers tell the user what a specific compressor is capable of producing. When trying to tell the difference between “technically” oil-free air and “actually” oil-free air, we talk about ISO Class 1 and ISO Class 0.


ISO Class 1: ISO can be thought of as a measure of air purity. ISO Class 1 is what we would think of as “technically” oil-free. It refers to compressed air with an oil concentration equal to or less than 0.01mg/m3 for 1 bar of pressure at 20 degrees Celsius. While there is very little oil present here, there is still the danger of filtration failure in sub-par compressor systems, leading to oil contamination from any used lubrication.


ISO Class 0: If absolutely no oil can enter the air stream, then ISO Class 0 is what you need. This standard was arrived at in 2010 and ensures that there are no oil particles, including vapour. This strict standard is used by BOGE in a number of its air compressors.


Why You Need to Know What Oil-Free Means

Because terms like oil-free and technically oil-free are used interchangeably with class 0 oil-free air, many businesses and individual consumers end up buying compressors which are not suitable. Not only that, but in the worst case scenarios, purchasing the wrong air compressor results in expensive and even dangerous operation.


Think of medical air. Patients cannot breathe any oil particles, and so class 0 air is a must. Likewise, in electronics manufacturing, pharmaceuticals, food and beverage production, and even textiles, oil can cause contamination of products which will prove costly, even potentially hazardous, to the customer.


When in doubt, buy class 0.


Buy Oil-Free Class 0 Air Compressors With Confidence

If you need Class 0 air, produced reliably, with a low carbon footprint, BOGE's line of truly oil-less air compressors are a great option at a competitive price. Feel free to peruse our products today. If you have any other queries, our BOGE air compressor experts are waiting to meet your needs.