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MESYS Calculation Software

The contamination factor is used for the calculation of life modification factor aISO. It is considering the cleanness of the lubricant and can be calculated with the viscosity ratio, the bearing size and a selection of oil cleanness according ISO 4406. The selection according ISO 4406 defines how many particles of certain size may exist.

Also an own input of the contamination factor can be selected and the factor can be entered using the all_img3-button.  The contamination factor is in the range from 0.1 to 1 and guide values can be selected according (ISO 281, 2007):

Contamination level


Dpw < 100mm

Dpw ≥ 100mm

Extreme cleanliness
Particle size of order of lubricant film thickness, laboratory conditions



High cleanliness
Oil filtered through extremely fine filter; conditions typical for bearings greased for life and sealed 0.6

0.9 to 0.8

Normal cleanliness
Oil filtered through fine filter; conditions typical for bearings greased for life and shielded

0.6 to 0.5

0.8 to 0.6

Slight contamination

0.5 to 0.3

0.6 to 0.4

Typical contamination
Conditions typical of bearings without seals; course filtering; wear particles from surroundings

0.3 to 0.1

0.4 to 0.2

Severe contamination
Bearing environment heavily contaminated and bearing arrangement with inadequate sealing

0.1 to 0

0.1 to 0

Very severe contamination




Note that for small bearings, the values for eC calculated from oil cleanliness can be much lower than in the table.