Collector Size and Test Duration Effects on Sprinkler Water Distribution Measurement

AN automated indoor sprinkler testing facility was used to study the influence of collector diameter and test duration on the uncertainty in depth of water caught. Greater variability near the sprinkler and the wetted radius than in the mid-range was assumed to be caused by the impact arm spray near the sprinkler and jet interruption, respectively. Coefficient of variation (CV) of water application decreased as collector diameter increased and as test duration increased. Variation decreased with volume caught by a collector (related to test duration and collector diamter) and thus CV could be estimated from duration and diameter. In addition, for larger collectors, fewer tests were needed to reach a stable CV. Thus, larger collectors are recommended to maintain accuracy and reduce the duration and number of tests.