BS 8465:2010

Defines methods to assess the level of particulate contamination in hydraulic liquids using an optical microscope. It includes assessment by two manual methods using either transmitted- or incident-lighting systems.

This British Standard specifies methods to assess the level of particulate contamination in hydraulic liquids using an optical microscope. It includes assessment by two manual methods using either transmitted- or incident-lighting systems. It also includes procedures for evaluating and controlling the accuracy of the technique that ensure reproducible results. This method is applicable to nearly all hydraulic liquids at a wide range of contamination levels, provided the samples can be filtered. However, the procedure requires modification for samples that are either heavily contaminated (e.g. > ISO -/20/17 according to BS ISO 4406) or lightly contaminated (< ISO -/12/10 according to BS ISO 4406), by decreasing increasing the volume of sample filtered. This procedure is not applicable to samples that have high concentrations of small (< 3 μm) particles (so called \'silt\'), gels or where overlapping particles are present on the membrane filter. The method detailed is a qualitative assessment only, not a quantitative evaluation, and it is applicable to all samples where the data has to be expressed in terms of contaminant codes. This procedure does not cover procedures for the extraction of fluid samples from systems or bulk containers.