This European standard specifies a method for the determination of the thickness of geotextiles and geotextile-related products at specified pressures and defines the pressure at which the nominal thickness is determined. The method is applicable to all geotextiles and geotextile-related products. Note: The thickness of geotextiles and geotextile-related products should normally be determined by measuring one layer of the product. When two or more layers are used on top of each other in a design, a test may be made in accordance with this European standard with the agreed number of layers.