ANSI/ASHRAE Standard 63.2 prescribes a method for measuring the filtration capability of liquid-line filters and filter driers for use in refrigerant systems.

It is recognized that the test contaminant, test fluid, test equipment, and method in the prescribed test do not fully represent the conditions that can exist in the liquid line of a refrigerant system. The specified test contaminant was chosen as the most nearly representative controlled-particle-size test contaminant commercially available. The wide range of controlled particle sizes used provides a satisfactory degree of repeatability of test results. However, it is recognized that seldom, if ever, will the composition, particle size, and mix of the test contaminant be duplicated in an actual system. Therefore, the filtration capability of a filter determined by this test does not necessarily predict its exact capability in actual service in a refrigerant liquid line. This test, however, serves as a useful means of comparing filter capabilities and implementing quality control to maintain uniformity of products.

The 2024 edition of Standard 63.2 includes updates to Informative Appendix B.