Abstract
For performance-based design, fire engineers commonly choose a design fire for use in computer modeling. Computer modeling requires the engineer to select a size and shape of the fire which is typically assumed to be a horizontal rectangular shape. Having chosen a heat release rate and a physical size for the fire, the engineer has defined a heat release rate per unit area (HRRPUA) often by default. However, the value of the HRRPUA can have an impact on the modeling results and thus on the design. Unfortunately, there is little guidance for choosing the HRRPUA. This paper outlines how the HRRPUA may be chosen by the engineer based on experimental results and the use of the Froude number to ensure that the flame is buoyancy driven. Values for the HRRPUA are suggested, and the Fire Dynamics Simulator (FDS) is used to demonstrate the impact that the HRRPUA has on the modeling results.
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Abbreviations
- A :
-
Area (m2)
- c p :
-
Specific heat (kJ/kg K)
- D :
-
Diameter of the fire (m)
- Fr :
-
Froude number (non-dimensional)
- g:
-
Gravitational constant (m/s2)
- h :
-
Height of storage (m)
- \( \overset{.}{Q} \) :
-
Heat release rate (kW)
- \( {\overset{.}{Q}}^{{\prime\prime} } \) :
-
Heat release rate per unit area (kW/m2)
- t :
-
Time (s)
- T :
-
Temperature (K)
- u :
-
Velocity of the fuel stream (m/s)
- ρ :
-
Density (kg/m3)
- a :
-
Ambient
- surface :
-
Surface
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© 2017 Springer Science+Business Media Singapore
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Fleischmann, C. (2017). Defining the Heat Release Rate per Unit Area for Use in Fire Safety Engineering Analysis. In: Harada, K., Matsuyama, K., Himoto, K., Nakamura, Y., Wakatsuki, K. (eds) Fire Science and Technology 2015. Springer, Singapore. https://doi.org/10.1007/978-981-10-0376-9_42
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DOI: https://doi.org/10.1007/978-981-10-0376-9_42
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