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MESYS Calculation Software

For the calculation of modified life, the definition of the lubrication is needed. The lubricant viscosity is calculated for the lubricant temperature using the reference values at 40°C and 100°C.

The selection ‘Consider lubrication’ defines if the modified life Lnmrh and the data for lubrication is shown in the report. For a small rotation speed, there will be no effective lubrication and the  aISO factor approaches 0.1.

The lubricant cleanliness is considered by the factor eC. It can be selected if the lubricant contains effective EP additives which can have an influence on  aISO factor for small speed.

The eC Factor can either be defined by lubricant cleanliness or it can be input by the user. An overview of recommended eC factors is shown in the following table:

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