In the field of energy production, HEYgreen membranes count amongst the most powerful fabrics. The membranes produced for flexible gas containers and made of PVC coated polyester fabric are produced in various designs with special, dirt repellent surfaces. They are used both as internal membranes for sealing of gas storage spaces and as UV and weather resistant outer membranes or flame resistant weather protection hoods. Depending on the design, the single layer systems and inner membranes have a methane gas permeability (test temperature 23 ° C) between 130 and 500 cm³/ (m²*d*bar).