Setting of fire scenarios in performance based characteristic coefficient on the optimal quantity of concrete walls

China has no fire protection regualtion about the ancient buildings, and the research on this issue is limited in China.This paper proposes some very important issues in the setting of fire scenarios for ancient buildings, especially the spread of fire. It discusses the criterion and process of fire scenario setting. The integrity procedure of fire scenario setting includes the fire position set, the fire development curve set and the fire spread analysis. Two ways of the fire spread are proposed.