The standard defines a controlled test method to evaluate filter performance. Key elements of the test include:
- controlled airflow through the filter
- particle size measurement upstream and downstream
- calculation of particle removal efficiency for each size range
- evaluation of pressure drop across the filter
The results are used to determine the MERV classification.
Electrostatic Discharge and Appendix J
Some filters rely on electrostatic charge to enhance particle capture. АШРАЭ 52.2 includes Appendix J, which introduces a conditioning procedure to reduce electrostatic charge before testing. This process helps ensure that filter performance reflects long-term operating conditions rather than temporary electrostatic effects.