Design Fires and Actions

Abstract

This chapter addresses design fires in the context of structural fire safety. Figure 4.1 illustrates a typical structural fire engineering (SFE) design process. First, the design fuel load must be derived for the given space, which represents the potential energy that needs to be considered. Once the design fuel load is established, estimation of the fire exposure intensity on the structure is a key next step in the process. Specifically, thermal boundary conditions acting on structural and/or insulative exposed boundaries must be derived so that subsequent heat transfer analyses may be conducted to determine the temperature histories of the given structural system. Also, it is important to note that SFE typically only considers a subset of design fires, which are those that are uncontrolled (any cooling effects of active fire protection systems and/or manual intervention are neglected) and termed as structural design

Burnout resistance of concrete slabs: Probabilistic assessment and global resistance factor calibration

“…A value Γ = 1 corresponds to a heating phase close to the ISO 834 standard heating curve, while Γ > 1 implies that higher temperatures are reached earlier, resulting in a fire which is colloquially 'hotter' than the ISO curve. The opposite applies for Γ < 1 [34]. Moreover, the Eurocode definition distinguishes two types of fires, i.e.…”

“…These equations are valid for both fuel and ventilation controlled fires. It should be mentioned that in the special case where the equivalent reference compartment parameters are Oeq > 0.04, qt,eq < 75 MJ/m 2 and beq < 1160 J/(m 2 s 0.5 K), an additional parameter k needs to be taken into account as discussed in Hopkin et al [34]. This issue can however be avoided by choosing the reference thermal inertia beq ≥ 1160 J/(m 2 s 0.5 K).…”