1- Its great ability to prevent the permeability of water and liquids through it.
2- It must have high chemical, physical and mechanical properties.
3- To withstand all weather conditions that are exposed to it in terms of temperature changes or exposure to ultraviolet rays.
4- To have the ability to resist the influence of any chemicals or any salts found in the surrounding environment.
5- To retain its properties throughout the life of the project.
6- To be highly resistant to all stresses to which it is subjected except for tensile and tear stresses, and to have a great capacity for elongation.
7- The surface of the chips should be smooth, free of wrinkles and needle holes, and that it should be compatible with the nature of the soil in which it is used, as well as the characteristics of the surrounding material.
8- It should be taken into account that the specifications of the foil are proportional in terms of thermal, such as the stability of dimensions, longitudinal and crosswise, tensile strength, elongation and elastic modulus, while leaving ripples that allow expansion and contraction so that the chips are not exposed to a decrease in their mechanical properties.
