The test method is standardized in DIN 51581, CEC L-40-A-93 and ASTM D 5800. The oil sample is heated in a testing device, the evaporation crucible, and subsequently re tained at the testing temperature for exactly 60 minutes. Whilst the testing temperatures can generally be as high as 400°C, motor oils are usually tested at 250°C ±0.5°C.
A constant flow of air, brought about by a differential pressure, extracts the resultant oil vapours.
The airflow is accurately regulated by the integrated digital pressure controller. It can be read-off using an inclined manometer.
According to CEC specifications, the partial pressure should be equal to 20 mm water column(1.96 mbar).