Brick longitudinal
This was due to a constructive scheme with two internal brick longitudinal walls.
This decision, which has become generally accepted, when considering the layout from the point of view of universal use of the premises, has a number of disadvantages: the difficulty of replacing communications (ventilation, sewage) when changing the internal layout of the premises or their division; limiting the depth of the premises with engineering communications, which determines the use of only the corridor system in the educational case; The difficulty of operating engineering communications during their repair and change in the corridors - the main ways of evacuation.