NF ISO 11943:2021

This document sets out methods for: validate equipment used to prepare secondary calibration suspensions for automatic particle counters; perform on-line secondary calibration of automatic particle counters; pair two or more particle counters online, i.e. obtain the same number of particles of a given size with two automatic particle counters associated online; validate automatic in-line particle counting systems, with and without in-line dilution, such as systems used to measure the filtration efficiency of a hydraulic filter as described in the NFISO 16889closed-loop filter test.