The Key Techlogoy Research For Performance-based Digsn Of Underground Commercial Building

Because of the poor ventilation condition, no sunshine, less safety exits and long evacuation passages in underground commercial buildings, the quickly spreading fire and the heavy smoke will bring on occupants'hurt or death due to not evacuation in time when the fire occurs in these buildings. In consideration of the fire hazard in underground commercial buildings, many experts have made much study about the characteristics of fire spread, occupant evacuation and so on. But in the underground commercial buildings, most of the fire protection designs follow the prescriptive code in our country because of their particularity. With the fast development of these buildings, the performance-based design approach had gradually been applied to the fire design of large scale underground commercial buildings in our country. As the complementarity of current prescriptive code, the performance-based design approachs play an important role in the fire design of underground commercial buildings.In this article, the smoke movement, ventilation technique, occupant evacuation technique, fire and smoke protection technique of underground commercial buildings are discussed briefly. Fire designs of theses buildings are studied elementarily by performance-based approachs and solving methods are given: 1) reasonable fire and smoke compartmentation, smoke control system, available occupant evacuation route design are all based on the knowledge and mastery on smoke movement rules. Smoke movement characteristic of underground commercial buildings is analyzed and some research methods are summarized in this article. It is directed that computer simulation based on the mathematic model of smoke movement is the fire research trend; 2) During the fire, it is important that smoke prevention and discharge system are built because the temperature and toxic of smoke are main factors on occupant hurt or death. Smoke prevention and discharge methods, including existed problem of these methods, are analyzed in underground commercial buildings and the detail requirements are given. In this article, new points of the smoke prevention and discharge system are introduced by performance-based approachs to the certain underground commercial building; 3) Based on the occupant evacuation simulation technique, the basic rule of occupant evacuation is discussed in underground commercial buildings,further new idea to the design of occupant evacuation route, the number of evacuation exit and exit width are provided; 4) In underground commercial buildings, the present fire and smoke compartmentation technique is discussed and the new concept, the'safety island'acting as the fire and smoke compartmentation to solve the problem of occupant evacuation, is given aiming to the characteristic of the less safety exits in these buildings.