Introduction to Structural Fire Engineering
Class lecture is finished by 8th Jun You have two weeks to prepare and draft the course report Dead line to submit the course report: 25th June(Thursday) Send your course report to: Chensm@tongji.edu.cn
• Class lecture is finished by 8th Jun • You have two weeks to prepare and draft the course report • Dead line to submit the course report: 25th June(Thursday) • Send your course report to: Chensm@tongji.edu.cn
9.1 Introduction Structures for buildings are required to have fire resistance of minimum duration(typically,30 minutes to 2 hours)to enable occupants to escape and to protect fire fighters. Any structure must be designed and constructed,in the case of fire,it satisfies the following requirements: load-bearing function must be maintained during the required time, development and spread of fire and smoke within the building is restricted, spread of the fire to adjacent buildings is restricted, People within the building must be able to leave the area safely or to be protected by other means such as refuge areas,the safety of fire fighters is assured
9.1 Introduction • Structures for buildings are required to have fire resistance of minimum duration (typically, 30 minutes to 2 hours) to enable occupants to escape and to protect fire fighters. • Any structure must be designed and constructed, in the case of fire, it satisfies the following requirements: load-bearing function must be maintained during the required time, development and spread of fire and smoke within the building is restricted, spread of the fire to adjacent buildings is restricted, People within the building must be able to leave the area safely or to be protected by other means such as refuge areas, the safety of fire fighters is assured
Resistance to fire-Chain of events ⊙ Steel columns time 1:Ignition 2:Thermal action 3:Mechanical actions time 4:Thermal 5:Mechanical 6:Possible response response collapse
9.2 Temperatures in fires to consider a real fire as Temperature Pre-Flashover Post-Flashover 1000-1200°C consisting of three phases,defined as growth,full Natural fire curve development and decay. rapid temperature rise Flashover occurs in the period IS0834 standard fire curve following flashover, Ignition which is the point at Start of fire which all organic Time Keywords: IgnitionSmouldering Heating Cooling materials in the Control:Inflammability Temp./smoke Fire load Ventilation development density compartment spontaneously combust. Figure 9.1 Phases ofa natural fire, comparing atmosphere temperatures with the ISO834 standard fire curve
• to consider a real fire as consisting of three phases, defined as growth, full development and decay. • rapid temperature rise occurs in the period following flashover, which is the point at which all organic materials in the compartment spontaneously combust. 9.2 Temperatures in fires Ignition Smouldering Pre-Flashover Post-Flashover 1000-1200°C Flashover Ignition Start of fire Keywords: Heating Cooling Time Control: Inflammability Temp./smoke development Fire load density Ventilation ISO834 standard fire curve Natural fire curve TemperatureFigure 9.1 Phases of a natural fire, comparing atmosphere temperatures with the ISO834 standard fire curve