Temperature related changes in dimension in a column system, having at least one separating column, a column vessel and a coldbox with coldbox casing, can be compensated for by providing for axial and/or radial movement. The column vessel is connected to the coldbox casing slidably in the axial and/or radial direction by means of radial, rigid connecting members (3, 3a, 3b, 3c, 3d).