CWA 18309:2025

This document defines a standardized method for assessing the antibacterial effectiveness of air filtration media after exposure to a bacterial bioaerosol. The procedure includes the controlled generation and delivery of a bacterial aerosol, its contact with the test filter surface, and the subsequent evaluation of bacterial viability using both qualitative and quantitative approaches.
This method is applicable to various types of air filters, including but not limited to HEPA filters, HVAC filters, coated filters, and filters treated with antimicrobial agents. It establishes validation criteria for controls, inoculum quality, and test conditions to ensure reproducibility and comparability of results across laboratories and applications.
This procedure is specifically designed for air filters treated with antibacterial agents to confer antimicrobial properties. Untreated specimens of the same type and production batch shall be used as control specimens to assess the relative antibacterial performance under identical test conditions.
The method is intended for use in research, quality control, and product development. It may also be used to facilitate conformity assessment procedures and regulatory compliance, where relevant and applicable.