Pipe liners are exposed to a variety of loads, e.g. groundwater, road traffic, or the pressure of the earth. They need to be designed accordingly and have sufficient load capacity. The Young’s modulus is a key mechanical characteristic in this regard. It is measured by means of a three-point bending test on construction site samples. The measured Young’s modulus (or modulus of elasticity), is compared with the specification. In formulas, it is abbreviated as E . A greater Young’s modulus means that the material resists deformation more. A component made of a material with a high Young’s modulus (e.g. steel) is therefore rigid; a component made of a material with a low Young’s modulus (e.g. rubber) is flexible. What does this mean for our purposes?The glass mats we use are designed to fulfil the load capacity requirements in the cured liner. ADV 75 for instance has a Young’s modulus of 7500 N/mm².