Fire Technology

, Volume 50, Issue 2, pp 205–231 | Cite as

Predicting Spill Plumes with the Fire Risk Zone Model B-RISK

  • Roger Harrison
  • Colleen Wade
  • Michael Spearpoint


Recent experimental research on spill plume entrainment has developed a range of empirically-based formulae for smoke management design. These formulae form the spill plume entrainment model in B-RISK, a new fire risk zone model. This article describes the performance of B-RISK in predicting spill plume entrainment. Selected experimental data from the series of reduced-scale experiments used to form the new design formulae have been used for model validation, along with other full-scale experimental data from ‘hot smoke tests’ conducted to assess the performance of installed smoke management systems. B-RISK provides predictions of the plume clear-layer height that generally agree with experimental results within the range of experimental error. This gives confidence in its use to predict spill plume entrainment for smoke management design purposes.


Balcony spill plume Adhered spill plume Fire modeling Smoke management 

List of Symbols


Breadth of balcony or soffit (m)


Depth of gas layer (m)


Height of balcony or soffit above the floor (m)


Height of fire compartment opening above the floor (m)

\( \dot{m} \)

Mass flow rate of gases (kg/s)

\( \dot{Q}_{c} \)

Convective heat flow of gases below the spill edge (kW)


Volume flow rate of mechanical exhaust (m3/s)

\( W_{c} \)

Width of fire compartment opening (m)

\( W_{s} \)

Lateral extent of gas flow below the spill edge (m)

\( z_{s} \)

Height of rise of the plume above the spill edge (m)

\( z_{trans} \)

Height of rise of plume above the spill edge where there is a transition in the rate of entrainment to that of an axisymmetric plume (m)



Variable evaluated in the layer flow at the compartment opening


Variable evaluated in the plume at an arbitrary height of rise


Variable evaluated in the layer flow below the spill edge


Property of the 2-D spill plume


Property of the 3-D spill plume



The authors would like to thank BRANZ for providing funding from the Building Research Levy in support of this article. And the New Zealand government’s research, science and technology funding agency, the Ministry of Business, Innovation and Employment for their funding contributing to the development of B-RISK.


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Roger Harrison
    • 1
  • Colleen Wade
    • 2
  • Michael Spearpoint
    • 3
  1. 1.AECOM Fire and Risk EngineeringSt AlbansUK
  2. 2.BRANZ LtdPorirua CityNew Zealand
  3. 3.Department of Civil and Natural Resources EngineeringUniversity of CanterburyChristchurchNew Zealand

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