BS ISO 4407:2002

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Counting principle
5 Apparatus
6 Reagent and chemicals
   6.1 Reagent and rinsing and cleaning chemicals
   6.2 Liquids for transparentizing the membrane filter
       (transmitted-light method)
7 Glassware cleaning procedure
8 Calibration procedures
   8.1 Microscope calibration
   8.2 Determination of Effective Filtration Area (EFA)
9 Membrane filter preparation
   9.1 Sample preparation
   9.2 Blank analysis
   9.3 Separation of contaminants by vacuum filtration
   9.4 Evaluation of suitability for counting
   9.5 Mounting of membrane filters for observation under
       transmitted light
10 Particle sizing and counting procedure
   10.1 Particle sizing
   10.2 Selection of nominal magnification
   10.3 Statistical counting procedure
   10.4 Calculation of total count
   10.5 Verification of data
11 Expression of results
12 Identification statement (Reference to this International
   Standard)
Bibliography

Describes 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 also includes particle counting by two manual methods and image analysis, using either transmitted or incident lighting systems.

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≥2µm 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.