Abstract
An investigation is carried out to assess the two-flux model for evaluating the attenuation ability of a water spray curtain in fire protection. Transmittances calculated with this model are compared with the “exact” discrete ordinates solutions for a range of water curtains under practical conditions. The results show the unsuitability of the two-flux method under a collimated incidence boundary condition, even if some improvements could be expected with very small droplets. Whereas the diffuse incidence type provides relatively better results, it is more reliable for transmittance calculations. [S0022-1481(00)00101-8]