Impacto do cálculo da temperatura crítica no dimensionamento de materiais de revestimento contra fogo

Abstract

The consequences of a fire can be quite severe, and as a result, the main objectives of fire safety are the preservation of life and the reduction of property losses. To achieve these objectives, it is necessary to adopt a set of passive and active protection measures, among which are the fire protection materials, which act by delaying the rise in temperature of the steel and consequently increasing the fire resistance time of the steel structure. Despite the importance of these materials and the relevance of the topic in question, in Brazil, few researchers have dealt with this subject. In addition, information about the behavior and properties of these materials at high temperatures is still quite limited, leading to the current practice of specifying material thickness based on fixed critical temperature values, such as 550 °C for column and 620 °C for beams. However, these temperature values are applied to all types of elements without considering their particularities of exposure to fire. Thus, in this work, a computational tool was developed to assist in the design of steel structural elements in fire situation and fire protection materials, which determines the critical temperature of steel columns and beams. A parametric study was carried out investigate the effect of different variables on the critical temperature of the structural element, and the results were compared to fixed temperatures. The results showed that there is distortion in the amount of protection material when it is calculated using fixed temperatures. The most impacted structural element is the column subjected to pure compression, in which calculating the critical temperature results in fire protection material savings of up to 39%. Furthermore, among the materials studied, the calculation of the critical temperature had the greatest impact on the thickness of intumescent paint.