several fireproof layers i ii iii of an insulating material are housed between the two outer layers 2 1 or 3 1 which has a retarding effect in case of fire so that a maximum permissible threshold value load on the information technology device will not be exceeded for 90 minutes for example the corner area between the side wall element s and the ceiling elements d is covered by means of an angled profiled lining 2 2 wherein the vertically downward oriented leg of the profiled lining 2 2 extends over the connecting area between the side wall elements s and the ceiling element d the adjoining edges of the side wall element s and of the ceiling element d are complementarily designed in an l shape so that the side wall elements s and the ceiling elements d can be easily and clearly put together with good sealing sealing means with an expansion seal 2 5 arranged in the center of the cross section with high temperature seals 2 6 arranged laterally of the expansion seal 2 5 with a sealing tape 2 7 arranged on the outside and with a sealing material 2 8 provided between the sealing tape 2 7 and the high temperature seal 2 6 are arranged between the long sides of the side wall elements s and the ceiling elements d the critical connecting points are designed to be fireproof with this sealing design connecting tongues 2 4 adjoin the sealing means at the front with respect to the.