tight interior surface of the entire expansion tent it has precisely one opening at which it is gastightly connected to the container 3 along the circumference of the container opening together with the walls of the container 3 the cover 4 forms the boundary surface between the contaminated exterior area and the interior area to be kept clean in the illustrated advantageous embodiment the cover 4 is permanently and flatly connected with the tent segment 2 away from the container specifically on the surface which in the erected condition of the tent segment 2 forms the inward facing surface this fastening of the cover to the tent segment 2 has the effect that as a result of the rolling out and unfolding of the tent segment fig4 away from the container the cover 4 connected with the latter is also rolled out and unfolded the rolling out of the disassembled tent segment 2 away from the container together with the cover 4 arranged thereon takes place through the already erected tent segment 1 close to the container in an embodiment not shown here the bag shaped cover is connected with none of the tent segments in the transport condition in this case the individual tent segments are first erected and mutually connected subsequently the unfolding of the bag shaped cover takes place in the interior of the tent over all tent segments so that the cover forms the interior surface of the expansion tent in fig5 the tent segment 2 away from the container is partially inflated the cover 4 is flatly connected with the tent segment 2 specifically on its entire inward facing side it is also shown in fig5 that in.