ISO/NP 22056-3

Aerospace series — Lubricant filter elements test methods — Part 3: Filtration efficiency

Scope

This part of ISO 22056 describes a method to measure in repeatable conditions the filtration efficiency of filter elements used in aviation and aerospace lubrication fluid systems. It can be applied when evaluating the overall characteristics of a filter element per ISO 22056-1, or separately.

Since the filtration efficiency of a filter element can change during its service life as it is clogging, this test method specifies its continuous measurement by using on-line particle counters with continuous injection of test contaminant and recirculation of particles not retained by the test filter element until the differential pressure across the element reaches a given final or "terminal" value.

This test procedure describes the laboratory conditions for tests and will need to be augmented by system level testing including actual conditions of use, for example the operating fluid or contamination.

The test data resulting from application of this part of ISO 22056 can be used to compare the performance of aerospace lubricant filter elements.