Safety Tech Talk | OIL MEASUREMENT in accordance with DIN EN 12021:2014

A frequent reason for misinterpretations is the definition of the term “oil”. ISO 8573-1 defines the oil content in compressed air as liquid and vaporous oil content, the so-called total oil content for hydrocarbons from C6 (purity class) and higher.

Lubricating oils for compressors contain hydrocarbons from C10 to C40, primarily C20 to C30. Do bear in mind that, more than measuring the gaseous content, it is most important to measure oil in aerosol form, as it can produce many times higher amounts of moist oil vapor when the temperature rises.

VOC measuring devices usually operate with PID sensors. These sensors only detect substances in gaseous form, which means up to C10 at the best.

They do not measure aerosols, oil in droplet or vaporous form, and no residual oil.


In oil lubricated high-pressure compressors VOC measurements with PID sensors cannot fully meet the requirements of DIN EN 12021:2014.


If you want to measure oil in order to meet the requirements of DIN EN 12021:2014, have the respective supplier confirm in writing that the measuring device really detects residual oil (within the meaning of DIN EN 12021:2014) and oily substances in liquid and aerosol form and that it reliably measures their percentage in the air.

Only then, you, as the operator, can be sure that the requirements of DIN EN 12021-2014 will be met and that you do not incur a liability risk.

IDE AIRSAVE OilControl reacts directly to oil the compressed air actually contains–be it in aerosol, vaporous or gaseous form.

The IDE AIRSAVE OilControl sensor for residual oil uses the established MHCM dynamic process, since many years considered to be a unique method for measuring the true oil content in compressed gases containing oil in any form.