ASSESSMENT OF FIRE-PROTECTIVE ABILITY OF VERTICAL PROTECTIVE MEMBERS FOR LOAD-BEARING BUILDING STRUCTURES

Abstract

The procedure for assessing the fire-protective ability of products and systems intended for fire protection of building structures applicable at the European level has uncertainties and requires clarification. Therefore, research aimed at improving and developing this evaluation procedure is relevant, in particular for vertical protective member for fire protection of load-bearing structures. The article identifies the experimental and computational components of the improved procedure for assessing the fire-protective ability of vertical protective member to protect load-bearing structures made of steel, reinforced concrete, reinforced concrete or timber. This procedure is based on the provisions of European standards EN 13381-2, EN 13381-4 and EN 13381-8, which regulate test methods for determining the effect of vertical protective members, passive and reactive fire protection systems of steel structures on the fire resistance of load-bearing building structures. It also applies the provisions of the European Building Codes in the European standards EN 1991-1-2, EN 1992-1-2, EN 1993-1-2, EN 1994-1-2 and EN 1995-1-2, which establish methods of calculating the fire resistance of building structures made of steel, reinforced concrete, reinforced concrete or timber. The application in the computational component of this procedure of two alternative approaches is substantiated, in one of which the results of temperature measurement in the cavity are used as a boundary condition in solving the thermal problem. In another approach, the effective thermal conductivity of a vertical protective member is determined by measuring the temperature in the cavity and on the surface of a steel column by solving the inverse thermal conductivity problem. It is shown that the proposed procedure allows to determine the parameters of load-bearing building structures, in particular the coefficient of cross section of the steel structure, and the thickness of the vertical protective member, which provide normalized fire resistance classes of these structures.