Fire Safety Science Digital Archive

This report describes the derivation of an empirical formula expressing the spray throw in terms of the nozzle pressure, the cone-angle of the spray, and rate of flow of water. Most of the data were taken from an American report describing tests made on spray-nozzles for the National Fire Protection Association. Some data were also avrailable from tests made by the Joint Fire Research Organization. The results indicate that the throw of a spray is as much dependent on the rate of flow and the cone angle as on the pressure. All these data referred to pressures between 50 and 150 lb/sq.in. but there is some additional evidence that the throw of sprays at pressures of 300 to 600 lb/sq.in. is much less than that given by extrapolating the data for low pressure sprays.