When zero is hero: Class 0 oil-free versus technically oil-free air
01 July 2019 | Web Article Number: ME201914879
OIL-free compressed air is used throughout industry where the purest compressed air quality is critical to the end product and to the processes involved – such as in the pharmaceutical or food and beverage sectors.
That’s according to portable power and air solutions provider Rand-Air, which has a TUV Class 0 certification under the ISO 8573-1 standard.
The company’s Fleet Manager Craig Swart said the. evolution of this standard reflects the ever-increasing requirement for quality air for processes and end products.
“Class 0 is a more stringent industry standard where the total oil content is measured – not only aerosols and liquids but vapours as well – by the internationally recognised TUV organisation.”
Swart said Rand-Air sources its oil free compressors from Atlas Copco, which put these units through the most rigorous tests available; and which is now the first manufacturer to receive Class 0 Certification for all its oil-free products.
"However, in the field of air compressors, there are two terms which need to be understood – Class 0 and technically oil-free."
The latter term means that oil is injected into the compressed air and then removed afterwards using a filtration process. This involves an oil separator in the compressor, coalescing filters to remove most liquid oil, and then an activated carbon filter to remove oil vapours.
Swart cautioned that with technically oil-free compressors, during the filtration process failures can potentially occur – for example, separators can break and filters can become saturated. These factors are exacerbated when the operating temperatures are high.
When using a technically oil-free system, there are also other issues to consider such as ensuring that filters are regularly changed, treatment of the condensate and higher energy costs.
"At Rand-Air, all our PT-, PN- and Z- range of compressors are Class 0 oil-free, TUV-certified and we have a range of oil-free compressors to suit most applications," he said.
"So, if your requirement is for oil-free compressed air, why take the risk of potential damage to equipment or reputation?”