Abstract: The invention relates, on the one hand, to a prismatic, especially panel-formed thermal insulation element which is enveloped in a gas-tight foil and evacuated, whereby a stable core pre-formed from a porous material is completely enveloped in a single cut sheet of the gas-tight foil; as well as a manufacturing process for same comprising the following steps: a) Manufacture of a prismatic core corresponding to the desired form of the thermal insulation element from a porous material; b) Enveloping of the principal faces of this core with a single sheet of the gas-tight foil; c) At least partial welding together of the foil which is drawn tight around the core along the face of the core; d) Folding-in of the welded seam area of the foil against the face of the core; e) Stress-free folding-together of the areas of the cut sheet of gas-tight foil projecting beyond the core, covering and in flat contact with the end surface(s) of the core; f) Welding together of the folded-together areas of foil on at least on

Abstract: The invention relates, on the one hand, to a prismatic, especially panel-formed thermal insulation element which is enveloped in a gas-tight foil and evacuated, whereby a stable core pre-formed from a porous material is completely enveloped in a single cut sheet of the gas-tight foil; as well as a manufacturing process for same comprising the following steps: