The modular house that is firstly manufactured in a factory and secondly assembled in site is beneficial to shorten the construction period, to improve the construction quality and to reduce the construction fee. However, for fire protection, few research work has been studied in Korea, in which, in turn, the demand for the construction of the modular houses has never been increased, due to the fire safety issue. This study investigates the improvement of fire resistance of the modular houses. A gypsum board and an insulating material were applied to the beams and columns, and their fire resistance performance was examined. The results of fire tests showed that the board encasing system had the least damage and protected the substrate modular structures from fire for maximum 71 min. Hence, it can be expected that this new board encasing system can inspire other researchers who work for developing the fire resistance technique for the modular house in near future.

Structural steels are one of the most popular construction materials with a number of merits, such as cost-effectiveness, durability, lightweight, versatility, etc. However, when exposed to a high temperature, their thermal expansion rate is high and the strength reduces substantially, making the steel structures vulnerable to fire. So far, a number of studies have been performed to understand the behavior of steel in fire. Rigorous tests, from the material to structural level, have led the advancement of modeling techniques. Among various analytical techniques, one of the most widely used approaches is the finite element modeling (FEM). While FEM can demonstrate geometrical and material nonlinearities, due to the complexity, the approach may result in high computational loads to ensure the convergence. Thus, in this paper, a simple calculation method is instead used to understand the steel frame subject to fire, in conjunction with experimentally collected temperature and displacement data. Then, at each temperature (before and after critical temperature and the formation of plastic hinges), the effect of elevated temperature on global behavior is examined using frame analysis. Results of the study have demonstrated that when structural integrity is of concern, the critical temperature of the structure must be examined in terms of fundamental characteristics of the structure.

Fire doors are installed on the openings in buildings to protect fire spreading in the event of fire. In foreign countries, fire doors whose fire resistance performance is from 20 minutes to 180 minutes are installed depending on required fire resistance performance of where fire doors are installed. But, in Korea, it is difficult to protect fire spreading in the event of fire because fire doors only having integrity of 1 hour are installed regardless of the position of fire doors. Therefore, it is needed to improve the system related to fire doors by strengthening the required fire resistance performance depending on where fire doors are installed and introducing insulation performance. To do so, the performance verification of the existing fire doors must be done first. In this study, fire resistance performance of the steel fire doors which are used widely depending on core material was evaluated. As a result, most specimens had the integrity performance and secured insulation performance of around 10 minutes depending on core material.

Since the column members in buildings deal with both vertical and horizontal loads, appropriated amount of load should be estimated in order to evaluate the fire resistance performance of the columns under loaded condition. However, according to the ISO 834, the international standard for the evaluation of structural members, the fire resistance performance evaluation of column members is only based on the displacement and displacement rate under loaded condition in a standard fire. The purpose of this study is to suggest appropriate axial load ratios for the evaluation of fire resistance performance. The test conducted in this study produced appropriate axial load ratios for different slenderness ratios. They are expected to contribute to more accurate estimation of fire resistance performance and more efficient and cost-effective structural design.

This study aims to assess heat transfer analysis of RC columns and unstressed test by applying 500°C isotherm method, which is the strength deterioration estimation method of Eurocode, inorder to use it as basic data for fire engineering design. According to the heat transfer analysis and fire resistance experiment, it was decided an appropriate axial ratio of RC columns that have cross sections of 300 and 350 can be anticipated as 0.49 and 0.59.