Abstract: A process and an apparatus for blowing in inert gas and vacuum foaming of insulting panels: an upper shell and a lower shell defining the outer in-sight surfaces and a foaming cavity of a panel, are positioned between the opposing platens of a press, together with a peripheral frame for retaining the foam; the frame comprises an interior channel connected to the foaming cavity of the panel, respectively to an annular manifold arranged in one of the press platens. At first, air in the foaming cavity is removed by blowing in an inert gas through the interior channel of the foam retaining frame; successively the foaming cavity is connected to a vacuum source and a metered quantity of a polyurethane mixture with a pentane blowing agent is injected, allowing the mixture to flow and foam in the panel under the vacuum effect.