Technically oil-free versus 100% oil-free compressed air

Technically oil-free vs. 100% oil-free compressed air: differences according to ISO 8573-1

Compressed air is an indispensable energy source in industry. But not every compressed air quality is suitable for every application. The oil content in compressed air, in particular , plays a major role in product quality, process safety, and maintenance costs. In this blog post, we explain the difference between technically oil-free compressed air and 100% oil-free compressed air , as defined in ISO 8573-1 .

ISO 8573-1 is the international standard that classifies the quality of compressed air based on:

  • solid particles
  • water
  • oil

total oil content is considered : a combination of oil aerosols and oil vapor. The standard distinguishes between Class 1 and Class 0 , which are often confused.

Technical oil-free compressed air (ISO 8573-1 Class 1)
Technically oil-free compressed air meets ISO Class 1 , with a maximum oil content of 0.01 mg/m³ . This compressed air is usually produced with an oil-lubricated compressor , combined with high-quality filters that almost completely remove the oil. An activated carbon filter is often added to reduce the residual oil to 0.003 mg/m³.

Although this air is very clean in practice, it is not completely oil-free .

Advantages of technically oil-free compressed air

  • Lower investment costs
  • Energy-efficient solution
  • Suitable for most industrial applications
  • Widely applicable in production environments

Disadvantages

  • Small chance of oil in the compressed air if the filter fails (certainly not unthinkable, so a risk)
  • Not suitable for critical processes
  • Regular and correct maintenance is necessary

100% oil-free compressed air complies with ISO Class 0. This class is stricter than Class 1 and requires an oil content of less than 0.01 mg/m³ , with a manufacturer-guaranteed value. The compressed air is generated using oil-free compressors , thus structurally eliminating oil contamination.

Benefits of 100% oil-free compressed air

  • Maximum security against oil pollution
  • Ideal for food & beverage , pharmaceutical and electronics
  • Protects product quality and brand reputation
  • Minimal chance of rejection and process disruptions

Disadvantages

  • Higher purchase costs
  • Often higher energy consumption
  • More complex installation and technology

Technically oil-free or 100% oil-free: what’s the right choice?
The right compressed air quality depends entirely on the application. For many industrial processes, technically oil-free compressed air (Class 1) is a reliable and cost-effective solution. In sectors where even the slightest oil contamination is unacceptable, such as the food industry, pharmaceuticals, or medical technology , 100% oil-free compressed air (Class 0) is the best choice.

Conclusion
A conscious choice for the correct compressed air quality according to ISO 8573-1 prevents product contamination, reduces risks, and saves costs in the long run. By understanding the difference between technically oil-free compressed air and 100% oil-free compressed air , you make a future-proof and safe choice for your process.