Abstract
When a fire occurs, the opening jet plumes ejected from an opening cause fire damage to adjacent space in a building. Especially it is considerable to be vital to control smoke from fire room facing vertical space such as atrium to prevent from damaging upper spaces. Then the purpose of this study is grasping the influence of horizontal soffit against opening jet plumes. In this study, a series of experiments were carried out by changing the opening shape, the depth of horizontal soffit, the length of smoke curtain, the diameter of source of fire etc. As the results, the knowledge about opening jet plumes in adjacent space with presence of a horizontal soffit could be obtained. It is possible to model the flow rate of the opening jet plumes by coefficient of involved air as parameter of opening shape and the depth of a horizontal soffit etc.