This European Standard specifies requirements relating to the construction, performance and methods of testing for membrane separation systems with a particle rating below 1 m, namely microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) for drinking water installations inside buildings, intended to remove from the drinking water marginal concentrations of suspended and colloidal solids, microorganisms, organic molecules and/or to reduce the dissolved solids concentration and applies to systems with a minimum pressure of PN 10, connections between DN 15 and DN 100 and a maximum working temperature of at least 30 °C. This European Standard applies to membrane separation systems, whose elements may be partly or entirely cleanable or disposable in accordance with the type of system. It only concerns units which are permanently connected to the mains supply at the point-of-entry or the point-of-use. A membrane separation system may include, together with the separation device pre- and /or post-treatment devices. For the scope of this European Standard: - separation device shall comply with this European Standard, i.e. without pre-and/or post-treatments; - where pre-and/or post-treatment devices are incorporated in the system, each of them shall conform to the relevant standard. If this is the case, the complete system shall be considered as conforming as a whole.