Fire Safety Science Digital Archive

Characteristics of single sprinkler sprays for three selected upright sprinklers were investigated with the FMW: drop size measuring system. The sprays of sprinklers with nominal orifice sizes of 16.3, 13.5, and 12.7 mm were mapped out at water pressures of 206 and 393 kPa and at 3.05 and 6.10 m below the sprinklers in a measuring sector whose bisector was perpendicular to the sprinkler pipe. Correlations of gross drop size distributions were derived based on the measurements. The gross drop size distributions at the 3.05 m level could be reproduced with the data measured at the 6.10 m level. The gross drop size distributions of the tested sprinklers can be represented by a composite of a lognormal distribution and a Rosin-Rammler distribution. An economical test protocol was also developed to quantify the spray characteristics of commercial sprinklers.