Explosions in buildings: modeling and interpretation of real accidents

Real explosions in domestic structures (Rasbash and Stretch, Struct. Eng 1969;47;403-11) and industrial plants (Howard, Loss Prevention 1972;6;68-73) have been analyzed. Deflagration dynamics are solved for enclosures of volumes of 130-8000 m³ for vent release overpressures in the range of 0-0.21 bar, and for different inertia of covers over the venting spaces in the range 0-15 kg/m². From comparisons of the real explosion data with the modeling of pressure-time behavior during vented gaseous deflagrations according to an earlier lumped parameter theory values of the main parameter, a turbulence factor, χ, are obtained. The results suggest the combustion is highly turbulent for real conditions in domestic structures (turbulence factor χ ≥ 8 with discharge coefficient μ = 0.6) and especially in large-scale enclosures such as a plant, with internal obstacles (turbulence factor χ ≥ 17). On the basis of the devised effective turbulence factors (the ratio χ/μ) the design procedures for avoiding the development of excessive overpressures during deflagrations, in both domestic and industrial plant, can be improved.