* Corresponding author. Tel.: 00-95-521-9157; fax: 00-95-521-9157. E-mail address: vniipo-3.4@mtu-net.ru (V.V. Molkov) Fire Safety Journal 33 (1999) 45 } 56 Explosions in buildings: modeling and interpretation of real accidents V.V. Molkov* All-Russian Research Institute for Fire Protection, VNIIPO 12, Balashikha-3, 143900 Moscow region, Russia Received 30 October 1995; received in revised form 21 May 1998; accepted 10 September 1998 Abstract 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. De#agra- tion dynamics are solved for enclosures of volumes of 130}8000 m for vent release overpres- sures in the range of 0}0.21 bar, and for di!erent inertia of covers over the venting spaces in the range 0}15 kg/m. From comparisons of the real explosion data with the modeling of pressure- time behavior during vented gaseous de#agrations according to an earlier lumped parameter theory values of the main parameter, a turbulence factor, , are obtained. The results suggest the combustion is highly turbulent for real conditions in domestic structures (turbulence factor *8 with discharge coe$cient "0.6) and especially in large-scale enclosures such as a plant, with internal obstacles (turbulence factor *17). On the basis of the devised e!ective turbu- lence factors (the ratio /) the design procedures for avoiding the development of excessive overpressures during de#agrations, in both domestic and industrial plant, can be im- proved.  1999 Elsevier Science Ltd. All rights reserved. Notation A radius of spherical vessel of equivalent volume a acceleration, m/s E  expansion coe$cient at initial conditions ("M  ¹  /M  ¹  ) F vent area, m f  surface area of imaginary sphere to which burnt gases may be collected at any moment, m f  real area of turbulent #ame at any moment, m i inertia of vent cover, kg/m M molecular mass, kg/kmol 0379-7112/99/$ - see front matter  1999 Elsevier Science Ltd. All rights reserved. PII: S 0 3 7 9 - 7 1 1 2 ( 9 9 ) 0 0 0 0 3 - X