Heat flow avaliation in closing system in light steel framing.

Abstract

The use of steel in construction appears as an alternative to change the overview of this sector, contributing to increase productivity, reduce waste and the running time of construction. The Light Steel Framing System (LSF) introduced in Brazil in the late 1990s is going through a process of technical development and acceptance in the domestic construction market, but there are still shortcomings in the design, detailing and implementation of complementary systems of closing and also in its thermal performance. This study covers an analytical approach in which simplified methods of calculating resistance and thermal transmittance and a numerical approach are presented, using the computer program ANSYS (version 15) for checking and comparing of these methods. It is considered the closing of multi-layer compound in the outer layer by cement board and the inner layer of gypsum board, brokered by fiber glass insulation, with studs formed by C-sections profiles in galvanized steel. Among the simplified methods discussed in analytical analysis, the method of Isothermal Plans showed the lowest value of thermal resistance and thus the highest thermal transmittance and heat flow. In relation to the numerical analysis, the results showed that the heat flow is equal to a value around 49% higher than the heat flux value for a closing without the presence of steel profile. The method of Modified Zone showed the smallest difference in the value of the equivalent thermal resistance in comparison of analytical and numerical analysis.