Thomas' Flashover Correlation

This tool calculates the heat release rate necessary for flashover for a given compartment geometry and vent opening.

Theory

The expression derived by Thomas for the minimum rate of energy release required for flashover comes from experimental data and is shown below. This assumes an average q'loss of 7.8AT, an upper layer gas temperature change of 600oC for flashover, and a cp of 1.26 kJ/kg*K.
Q' = 7.8AT + 378AOHO1/2
where
  • AT = total area of compartment enclosing surfaces (m2)
  • AO = area of opening (m2)
  • HO = height of opening (m)
Metric English
Room Length:
Room Width:
Room Height:
Vent Height:
Vent Width:
Q'FO = kW

Instructions

  1. Select Metric or English units
  2. Enter room geometry
  3. Click on the "GO" button
Equations used are from The SFPE Handbook of Fire Protection Engineering, 2nd edition, page 3-146.
Send e-mail to: ierardi@wpi.edu

Last Modified: Fri 22 Aug 18:07:45 EST

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