There is a need to qualify ultrafiltration and nanofiltration membranes with a standardized methods.

Two specific protocols have been developped and proposed by AFNOR (french normalization committee) to determine the filtration ratings of membrane at size lower than 1 µm.

A first protocol (under NFX 45 103 reference) is based on macromolecules retention under a differential pressure and can be applied upon crossflow and dead end filtration membranes.

A second protocol (under NFX 45 -104 reference) is based on latex beads retention of size (0.1-1 µm) and is applied on dead-end filtration membranes in steady flow conditions.

The interest of such normative protocols is to express a reference filtration rating (in µm) to characterize in a reproducible way a filtration membrane. This is a need for end-users to help them choosing the different available membranes in the market.