This European Standard specifies the relevant characteristics of geotextiles and geotextile-related products used in the construction of reservoirs and dams, and the appropriate test methods to determine these characteristics. The intended use of these geotextiles or geotextile-related products is to fulfil one or more of the following functions: filtration, separation, reinforcement and protection. The separation function is always used in conjunction with filtration or reinforcement, accordingly separation will never be specified alone. This standard is not applicable to geomembranes.