The final question you have to answer is whether you need an oil-free compressor. This is primarily an issue of air quality (although all compressed air systems benefit from clean air in some ways).
Therefore, to answer this question, you need to understand your air quality requirements. But before we get to that, you first have to understand why air quality is so important.
Generally, oil and other contaminants in your air are a bad thing. In the compressed air system itself, as well as in any downstream equipment, the contaminants can lead to reduced service lives and higher maintenance costs.
In end products, these contaminants can cause even worse – and more expensive – problems. For example, imagine a company working in the food and beverage sector that allows oil residue to get into its products. Or what about a pharmaceutical manufacturer whose prescription drugs are contaminated in that way?
The consequences could be disastrous: Sick customers, expensive recalls, lawsuits …
So how do you avoid these problems? It all starts with knowing your air quality requirements.
Different applications have different air quality obligations. In some cases, air quality hardly matters. For example, if the compressor powers a jackhammer on a construction site, the quality of the compressed air it produces is not as important as its reliability.
That is obviously not the case for a compressor that operates in a cleanroom environment. Here, air quality is the top priority.
To navigate your air quality requirements, you should either contact the experts of Atlas Copco or consult the ISO standards for compressed air.
If you need top-quality air, you have to properly treat it. And that begins with an oil-free compressor. While oil-injected compressors use oil for lubrication and to prevent corrosion, as a sealant and to cool the compressed air, oil-free compressors do not.
It is important to note that this does not mean that there are no traces of oil in the compressed air produced with an oil-free compressor. The reason for this is that there is also oil in the ambient air that is being compressed. However, these trace amounts can be cleaned with the help of filters or other air treatment equipment.
While oil-free compressors are more expensive, they are essential to the production of a wide range of sensitive products – from semiconductors, medication and paper.
ISO 8573-1 (ed. 2010) is the most important internationally recognized air quality standard. It is divided into seven air quality classes and the three main types of contaminants (oil, particles and moisture). ISO 8573-1 will serve as your essential guide to determine how clean your air has to be. Essentially, it defines how many contaminants your air is still allowed to contain at a specific point in your compressed air system after it has been treated.
In some cases, this figure can be quite high. For example, if your application calls for Class 6 air, then it can contain any number of solid particles. Class 0, on the other hand, is reserved for the cleanest air.
Therefore, the most important (and stringent) classes are Class 1 and Class 0.
Class 1 specifies an oil concentration of 0.01 mg/m3 at 1 bar(a) 14.5 psia and 20°C (68°F). It is sometimes referred to “technically oil-free solution.”
Class 0, on the other hand, is the only category that is absolutely oil-free.
That is why, when choosing an oil-free compressor, make sure to pick a Class 0 oil-free compressor and not a “technically oil-free” option.
