Walls and ceilings that are elements of fire separation, should be made of non-flammable materials, and their openings are enclosed with fire atriums or closed with fire doors, or another fire closure. The total area of ​​these openings in the case of their presence in the wall of the fire separation (e.g. door, windows, installation culverts) should not exceed 15% surface of that wall, and in the case of their occurrence in the ceiling, fire separation (e.g. installation culverts) – 0.5% floor surface.
The fire-prevention vestibule should have dimensions of the horizontal projection not less than 1.4×1.4 m, walls and ceiling, and power cable sheaths or housings – except for those used in the vestibule – with a fire resistance class of at least El 60, made of non-combustible materials and be ventilated and have doors equipped with devices that automatically close them in the event of fire. A section of the corridor can play the role of a fire-fighting vestibule, having in addition to the door leading to the staircase, also doors leading to the rooms, possibly also to the rest of the corridor.
Fire resistance class (He) installation culverts in the fire separation elements should be equal to the fire resistance class of these elements, however, it is allowed not to install this type of culvert for single pipes of water systems, sewage and heating systems, led through walls and ceilings into hygienic and sanitary rooms. For culverts with a diameter greater than 4 cm, located in walls and ceilings that are not elements of fire separation, for which a fire resistance class of at least El is required 60 or REI 60, the fire resistance class of the culverts should be equal to the fire resistance class (He) these walls and ceilings, where they are located.