INCREASE THE CABLE RESISTANCE TO THE FLAME DISTRIBUTION THROUGH THE FACING OF THE METAL CABLE BOXES WITH REACTIVE FIRE PROTECTION MATERIAL
To ensure compliance with the basic requirements for buildings and structures to limit the spread of fire in them during a fire, the provisions on the use of cables resistant to flame propagation at construction sites are given in building codes.To ensure this resistance, constructive solutions are used, which consist in the use of special plastics for cable sheathing or covering the surface of cables with fire protection materials. However, these constructive solutions are not always possible to implement in practice and the actual task is to identify other solutions that limit the spread of fire (flame) through cables within the room where the fire broke out, which is what the study in the article is dedicated to. During this study, the acceptability of a constructive solution was determined, which consists in the use of reactive fire protection material on the inner surface of a metal cable box, to ensure that the spread of flame through cables located in this box is limited. For the research, the methodology based on the provisions of DSTU EN 60332-3-10:2013 and DSTU EN 60332-3-22:2013 was applied. The essence of this technique lies in the fact that a bundle of category A cables, a class unstable to flame propagation, located inside a metal cable box, through a rectangular opening in the box cover for 40 minutes, is exposed to the flame of two special belt burners. After the termination of the impact of this flame, the length of the charred part of the cables is determined and compared with the boundary value, which is 1.5 m. According to the results of the study, the peculiarities of the flame propagation process through cables laid in a metal cable box, the inner surface of which is coated with a reactive fire protection material, have been established. A constructive solution has been defined that limits the spread of flame through cables laid in a metal cable box within the room where the fire occurred. The direction of further research, which is focused on identifying the influence of the volume coefficient of expansion of the reactive fire protection material, which covered the inner surface of the metal cable box, on the resistance of the cables to flame propagation, has been established.