filterklasse

Filterklasse (German for "filter class") is a generic term used to describe the category or class of a filtration device or process according to its performance characteristics. The concept is context-dependent and there is no single universal standard for what constitutes a given filter class.

A filter class is typically defined by factors such as pore size or retention rating (often expressed in micrometres or by removal efficiency), filtration efficiency, flow resistance or pressure drop, material compatibility, and the physical form of the filter (media, cartridge, bag, or membrane). These factors determine suitability for a particular application and help users compare different products.

In practice, different domains use different classification schemes. In air filtration, classes often reflect particle removal effectiveness, with standards and labels such as HEPA or ULPA in some regions, and EN 1822 classifications (for example H13, H14) in others. Residential filters may be described by approximate efficiency ratings (for example, MERV-like scales). In water filtration, classes are commonly defined by nominal or absolute micron ratings and the media used (activated carbon, ceramic, or membranes). In respiratory protection, filter class designations such as FFP1, FFP2, and FFP3 indicate protection levels under applicable standards. In industrial liquid filtration, classes differentiate media by pore size, material compatibility, and performance under expected flow and chemical exposure.

The purpose of a filter class is to enable comparability and appropriate selection for safety, hygiene, or process requirements. Manufacturers publish the class in product specifications, and buyers use it as a basis for meeting regulatory and performance criteria. See also related standards such as EN 1822, EN 149, and regional labeling schemes.