NOVELTY - A covering has an interior membrane (102) at least partly covering the inner volume (Vs,i) for industrial gas in the gas storage (100), and an exterior membrane (101a,101b) covering the interior membrane as such that the membranes define an outer volume (Vs,o) in-between to store support gas. The exterior membrane, as well as the interior membrane, can be formed of material with ultimate elongation of more than 100 percent. The material may be thermoplastic elastomer, in particular a synthetic rubber such as ethylene propylene diene monomer (EPDM).    USE - Covering for gas storage for industrial gas (claimed) or gaseous medium such as natural gas or liquid gas. Can also be used for bio gas storage (claimed).    ADVANTAGE - Due to the stretchable characteristic of the material used to make the exterior membrane, manufacture of the exterior membrane in form of a plane or conical or cylindrical shape is easy and cost-effective. Gas pressure in the inner volume below the membranes can be kept stably, ensuring stability of the membranes. The storage function is still provided, because the inner volume and positions of the membranes are still amendable. Since both membranes are stretchable, the gas storage can be operated even if leakage in the interior membrane occurs. By the defined curved shape of the stretched, folding-free interior membrane, the filling level of the inner volume can be measured more exactly. Due to the stretching and expanding properties of the exterior membrane, the area size of the same membrane is adaptable and amendable to the respective pressure of gaseous medium in the storage volume, preventing the same membrane from fluttering under influence of wind while tension on the membrane is kept. The curvature in the operating state of the gas storage is achieved by stretching the membrane due to gas pressure in the storage volume, simplifying tailoring of the exterior or interior membrane.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a gas storage for industrial gas; and    (2) a method manufacturing a storage for a gaseous medium.    DESCRIPTION OF DRAWING(S) - The drawing shows the sectional view of a gas storage for gaseous medium including the covering.    Gas storage (100)    Exterior membrane (101a,101b)    Interior membrane (102)    Inner volume (Vs,i)    Outer volume (Vs,o)