by means of correspondingly cut plate sections 6 and 8 i e they are involved in a box like fashion in the intermediate area intermediate plates 7 are introduced and all elements are attached to the cover construction with adequate metal clips 5 the plate sections 6 through 8 may preferably be formed also as integral molded section which is applied around the frames in such a way that in one operational step it embraces the frames without forming thermal bridges the plate material for plate sections 6 7 and 8 features in the example a surface weight of 2 3 kg m 2 with such a fire protecting construction it is possible to attain the fire resistance category a60 without problems the material resistance in the event of fire is insured due to the fact that the mineral wool fibers are selected in such a way that their point of fusion is located above 1 000 u00b0 c this will insure that also with fire resistance category a60 the insulating element of the invention is resistant for a sufficiently extended period of time i e one hour against the fire temperatures in the version shown the average geometrical fiber diameter is 3 2 u03bcm and the binding agent content is 1 8 weight the composition in weight of the conventional insulating elements i e molded section produced from traditional rock wool as well as insulating elements i e molded section produced from traditional glass wool results from table 2 and the traditional rock wool as well as the insulating element i e molded section of the.