Water permeability of porous filter media is an essential characteristic in the evaluation and design of filtration systems, as it directly reflects the hydraulic behaviour and flow resistance of these media. Several methods for measuring water permeability exist and are described in the literature, including methods working under constant and declining pressure conditions, and flow‑simulation‑based methods. Although fluid flow through porous media has been well studied, there is no standardized procedure for water permeability testing, and there is no consensus on units, test conditions, or instrumentation requirements. This work aims to present, explore, and describe the POROLUXTM Revo porometer extension for measuring water permeability.

In addition, the repeatability and the influence of the sample testing area and applied pressure on the resulting liquid permeability values are also investigated. The water permeability measurements were performed using a liquid permeability extension setup on the POROLUXTM Revo porometer. This device allows fully automatic measurement of liquid flow through a membrane or filter media at a predefined constant pressure. Three porous materials were selected for this study: a track‑etched membrane with a well‑defined porous structure having the mean flow pore size (MFP) of 1 µm, a PET membrane with an MFP of approximately 2 µm, and a nonwoven filter sample with an MFP of 7.8 µm.

Three different pressures, ranging from 0.05 to 1 bar, were applied to test the studied samples with different diameters of 13, 25, and 47 mm. In addition, measurement repeatability was checked. The water permeability measured with the POROLUXTM Revo setup showed good repeatability across the tested materials. However, the standard deviation for repeatability was higher for nonwovens than for membranes, e.g., [...]% vs. [...]%.

The sample size, as expected, influenced the water permeability. Interestingly, the 2-fold increase in the testing area led to approximately a ...