According to international recommendations, the upper floor is at a depth of 15 metres. Penetrating deeper our "pie" has the following layers: a living space, a floor with a water treatment system and generator, a layer of electrical equipment, and at the very bottom — a well.
The Plan B bunker has three exits, and the fire-resistant evacuation "ring" can be reached from almost anywhere. This is done in case of the event of danger inside the bunker, its inhabitants do not spend time getting out (especially given the floor area), but can immediately get to the evacuation route, for example, from the bathroom or gym.
Of course, all systems in the Plan B underground building are autonomous. Water supply, sewerage, closed ventilation system with recuperation, intake, and air purification. Whatever happens on the Earth's surface, life in Plan B will continue.
The systems will be developed in detail at the project stage together with specialized contractors. At present, we have developed a design proposal for the bunker, our own vision.
The main building mass is reinforced concrete, the strongest duo, and the optimal cost. The doors are automatic but have the option of manual control. Directly next to the entrance to the bunker, there is a disinfection shield, behind it — a quartz zone.
The main spiral staircase and elevator lead to the underground building, as well as two flights of spiral staircases for staff and loading stocks — so the flows are distributed and do not interfere with each other.