Fire Safety Science Digital Archive

Force-ventilation compartments are a common environment for fire growth in sealed or high-rise structures. Currently, no method exists for reliably estimating the fire hazard in these enclosures. Using data from compartment fires in the forced ventilation facility at the Lawrence Livermore National Laboratory (LLNL), a simple correlation has been developed following the methods of McCaffrey, Quintiere and Harkleroad. The upper layer temperature rise above ambient, AT = Tu - T,, is given as a function of: the fire heat release rate, Q, the compartment mass ventilation rate, in, the gas specific heat capacity, cp, the compartment surface area A and an effective heat transfer coefficient based on AT, h. The nondimensional form of the best fit to the LLNL data is :This confirms the correlation suggested by McCaffrey et a1 . For their free ventilation data the coefficient increases t o 0.77. A l l the data are well fit by a coefficient of 0.7, while the powers remain unchanged. Alternatives for, limits on, and usefulness of such correlations are discussed.