ISO 18471:2015 a test method for the verification of filtration grade of filters intended for operation in agricultural irrigation systems. It is intended to be used for verifying the filter manufacturer's declaration about the filtration grade of a specific filter. This test method uses a Clogging Capacity Meter (CCM) device to compare the filtration grade of the filter under test against the filtration grade of a test filtration screen. NOTE This test method may also be used by a filter manufacturer to determine the filtration grade.