Fire induced flows through room openings-flow coefficients

Abstract

A full-scale experimental and theoretical study was made of steady-state fire-induced flows through doorway and window openings. Measurements included two-dimensional temperature and pressure-difference profiles within the opening and vertical temperature profiles within the rooms connected by the openings. Gas burners served as the energy source. Mass flow rates through the openings were calculated from the opening data. A static-pressure flow model was used to establish ideal orifice flows. The opening and ideal flow results were combined to form room-opening flow coefficients as a function of fire energy release rate, opening geometry, and fire location. An irrotational jet model for the flow coefficients was developed and found to be in reasonable agreement with these and other measurements. Measured flow coefficient results show no significant dependence on fire strength, opening geometry, or fire location. The mean value of the inflow coefficient is 0.68 and 0.73 for the outflow coefficient. However, the theory indicates a significant variation in flow coefficient with opening widths larger than those used in the experiments.