A model experiment was performed in this research for the purpose of explaining the form of fire plume behavior ejected from opening flowing into a section adjacent to a fire section in a space with several openings at the fire section with the use of a model of rooms. Through such experiment, temperature distribution inside the fire section and adjacent section according to the conditions of opening were investigated and a model was constructed by calculating radiation heat added to combustibles at the adjacent section and calculated value of the calculation model and experiment value were compared to reveal the validity of the radiation heat calculation model. And a similar tendency was derived after suggesting a simple temperature forecasting model on the temperature of the adjacent section before the extension of combustion with the use of the suggestion formula by McCaffrey and comparing with the experiment value.