Assessment of Fire Engineering Design Correlations Used to Describe the Geometry and Thermal Characteristics of Externally Venting Flames

Eleni Asimakopoulou, Dionysios Kolaitis, Maria Founti

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Externally venting flames (EVF) may emerge through openings in fully developed under-ventilated compartment fires, significantly increasing the risk of fire spreading to higher floors or adjacent buildings. Several fire engineering correlations have been developed, aiming to describe the main characteristics of EVF that affect the fire safety design aspects of a building, such as EVF geometry, EVF centreline temperature and EVF-induced heat flux to the façade elements. This work is motivated by recent literature reports suggesting that existing correlations, proposed in fire safety design guidelines (e.g. Eurocodes), cannot describe with sufficient accuracy the characteristics of EVF under realistic fire conditions. In this context, a wide range of EVF correlations are comparatively assessed and evaluated. Quantification of their predictive capabilities is achieved by means of comparison with measurements obtained in 30 different large-scale compartment-façade fire experiments, covering a broad range of heat release rates (2.8 MW to 10.3 MW), ventilation factor values (2.6 m5/2 to 11.53 m5/2) and ventilation conditions (no forced draught, forced draught). A detailed analysis of the obtained results and the respective errors corroborates the fact that many correlations significantly under-predict critical physical parameters, thus resulting in reduced (non-conservative) fire safety levels. The effect of commonly used assumptions (e.g. EVF envelope shape or model parameters for convective and radiative heat transfer calculations) on the accuracy of the predicted values is determined, aiming to highlight the potential to improve the fire engineering design correlations currently available.
LanguageEnglish
Pages709-739
JournalFire Technology
Volume53
Issue number2
Early online date2 May 2016
DOIs
Publication statusPublished - Mar 2017

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Fires
Geometry
Facades
Ventilation
Roof coverings
Hot Temperature
Heat flux
Heat transfer
Experiments

Keywords

  • Externally venting flames
  • Fire plume
  • Façade fire
  • Large-scale fire tests
  • Centreline temperature
  • Heat flux
  • Fire engineering design
  • Flame height
  • Flame width
  • Flame projection

Cite this

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title = "Assessment of Fire Engineering Design Correlations Used to Describe the Geometry and Thermal Characteristics of Externally Venting Flames",
abstract = "Externally venting flames (EVF) may emerge through openings in fully developed under-ventilated compartment fires, significantly increasing the risk of fire spreading to higher floors or adjacent buildings. Several fire engineering correlations have been developed, aiming to describe the main characteristics of EVF that affect the fire safety design aspects of a building, such as EVF geometry, EVF centreline temperature and EVF-induced heat flux to the fa{\cc}ade elements. This work is motivated by recent literature reports suggesting that existing correlations, proposed in fire safety design guidelines (e.g. Eurocodes), cannot describe with sufficient accuracy the characteristics of EVF under realistic fire conditions. In this context, a wide range of EVF correlations are comparatively assessed and evaluated. Quantification of their predictive capabilities is achieved by means of comparison with measurements obtained in 30 different large-scale compartment-fa{\cc}ade fire experiments, covering a broad range of heat release rates (2.8 MW to 10.3 MW), ventilation factor values (2.6 m5/2 to 11.53 m5/2) and ventilation conditions (no forced draught, forced draught). A detailed analysis of the obtained results and the respective errors corroborates the fact that many correlations significantly under-predict critical physical parameters, thus resulting in reduced (non-conservative) fire safety levels. The effect of commonly used assumptions (e.g. EVF envelope shape or model parameters for convective and radiative heat transfer calculations) on the accuracy of the predicted values is determined, aiming to highlight the potential to improve the fire engineering design correlations currently available.",
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Assessment of Fire Engineering Design Correlations Used to Describe the Geometry and Thermal Characteristics of Externally Venting Flames. / Asimakopoulou, Eleni; Kolaitis, Dionysios; Founti, Maria.

In: Fire Technology, Vol. 53, No. 2, 03.2017, p. 709-739.

Research output: Contribution to journalArticle

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T1 - Assessment of Fire Engineering Design Correlations Used to Describe the Geometry and Thermal Characteristics of Externally Venting Flames

AU - Asimakopoulou, Eleni

AU - Kolaitis, Dionysios

AU - Founti, Maria

N1 - New member of staff at Ulster 1st February 2017

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AB - Externally venting flames (EVF) may emerge through openings in fully developed under-ventilated compartment fires, significantly increasing the risk of fire spreading to higher floors or adjacent buildings. Several fire engineering correlations have been developed, aiming to describe the main characteristics of EVF that affect the fire safety design aspects of a building, such as EVF geometry, EVF centreline temperature and EVF-induced heat flux to the façade elements. This work is motivated by recent literature reports suggesting that existing correlations, proposed in fire safety design guidelines (e.g. Eurocodes), cannot describe with sufficient accuracy the characteristics of EVF under realistic fire conditions. In this context, a wide range of EVF correlations are comparatively assessed and evaluated. Quantification of their predictive capabilities is achieved by means of comparison with measurements obtained in 30 different large-scale compartment-façade fire experiments, covering a broad range of heat release rates (2.8 MW to 10.3 MW), ventilation factor values (2.6 m5/2 to 11.53 m5/2) and ventilation conditions (no forced draught, forced draught). A detailed analysis of the obtained results and the respective errors corroborates the fact that many correlations significantly under-predict critical physical parameters, thus resulting in reduced (non-conservative) fire safety levels. The effect of commonly used assumptions (e.g. EVF envelope shape or model parameters for convective and radiative heat transfer calculations) on the accuracy of the predicted values is determined, aiming to highlight the potential to improve the fire engineering design correlations currently available.

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