High velocity system uses nozzles which are specifically designed to discharge a jet of water at high speed. The water jet forms a cone of coarse spray of uniform density which is able to penetrate the flame zone and reach the surface of the burning oil. The high velocity spray splits the oil into particle and the emulsion is produced on the surface of oil which will not burn. This “emulsification” is the principal way the fire is extinguished, along with a cooling and smothering effect. The key to the engineering is the selection of the nozzle specification, water pressure and the orientation of the nozzle. The application includes transformer, turbines and combustible liquid hazards.
Medium velocity water spray system: Wherever light hazards are involved and emulsification from high velocity sprayers is not possible, medium velocity spray nozzles are selected to discharge a water spray of finely divided droplets. This fine spray cools the exposed surfaces and protects the adjacent plant and structures from catching fire. The components of the systems are fire detection system, deluge valve system and piping leading to the nozzles.