BS ISO 11500:2022

Hydraulic fluid power. Determination of the particulate contamination level of a liquid sample by automatic particle counting using the light-extinction principle. | Status: Current, Under review

1 Scope This document specifies an automatic particle counting procedure for determining the number and sizes of particles present in hydraulic-fluid bottle samples of clear, homogeneous, single-phase liquids using an automatic particle counter (APC) that works on the light-extinction principle. This document is applicable to the monitoring of:

1. a) the cleanliness level of fluids circulating in hydraulic systems;
2. b) the progress of a flushing operation;
3. c) the cleanliness level of support equipment and test rigs;
4. d) the cleanliness level of packaged stock fluid.

NOTE Measurements can be made with particles suspended in the original liquid or in a sample of the liquid diluted with a compatible liquid when APCcoincidence error limits are exceeded.