90.92 Standard to be revised Nov 26, 2018
ISO
ISO/TC 131/SC 6 Contamination control
International Standard
23.100.60 Filters, seals and contamination of fluids
Published
This International Standard specifies methods for determining the level of particulate contamination in liquids used in hydraulic systems by counting the number of particles deposited on the surface of a membrane filter using an optical microscope. It includes particle counting by two manual methods and image analysis, using either transmitted or incident lighting systems.
Particle sizes greater than or equal to 2 micrometres can be sized and counted by this method, but the resolution and accuracy of the results will depend upon the optical system used and the capabilities of the operator.
All hydraulic fluids with a wide range of contamination levels can be analysed according to this International Standard. However, the counting uncertainty at the larger particle sizes increases if the volume filtered is reduced to allow smaller sized particles to be counted, where a fine precipitate or a high particle concentration is present.
WITHDRAWN
ISO 4407:1991
PUBLISHED
ISO 4407:2002
90.92
Standard to be revised
Nov 26, 2018