ISO Code for Hydraulic Oil Cleanliness

[nasirqa1407]

I referred to some website for ISO Code for Hydraulic Oil Cleanliness & I observed there are differences between the size of particles in each site. For example:
17/15/12: 17 is the quantity of particles greater than 2 micron. 15 is the quantity of particles greater than 5 micron. 12 is the quantity of particles greater than 15 micron.But, the other side shows: For example:17/15/12: 17 is the quantity of particles greater than 4 micron. 15 is the quantity of particles greater than 6 micron. 12 is the quantity of particles greater than 14 micron. My question is ISO has so many standerd or just one? if so many how can I know which one suppose to be used? if it is one standard what is the right quantities for the microns.

Thanks,

 

[WKTaylor]

nasirqa1407...

Per SAE AS4059 Aerospace Fluid Power - Cleanliness Classification for Hydraulic Fluids...

Refer to ISO 11218 Aerospace - Cleanliness Classification for Hydraulic Fluids

Regards, Wil Taylor

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[TVP]

ISO 11218 uses the following sizes:

> 2 micrometers
> 5 micrometers
> 15 micrometers
> 25 micrometers
> 50 micrometers