Measurements of Water Density and Drop Size Distributions of Selected Esfr Sprinklers

Characteristics of single sprinkler sprays for two Early Suppression Fast Response (ESFR) sprinklers were investigated. The water density, drop size and velocity distributions were measured at an elevation 2.85 m (9 ft 4 in.) below the sprinkler deflector for two water discharge pressures, 1.72 bar (25 psig) and 3.45 bar (50 psig). Measurements began at 0.61 m (2 ft) from the sprinkler axis and extended to near spray boundary. For every 0.61 m (2 ft) increment, the measurements were performed for 10 azimuthal angles with 45 degree intervals. The drop size and velocity distributions were measured with a PMS (Particle Measuring Systems, Inc.) optical imaging probe which can measure drop size ranging from 0.1 to 6.2 mm with a resolution of 0.1 mm.The results of the water density measurements indicate that the water densities for the two sprinkler models diminish with increasing radial distance from the sprinkler axis. Based on the local measured density data, the gross density distributions in term of volume...