Drift Comparisons of Low-Expansion Foams and Conventional Sprays

Experiments were conducted to compare the drift of low-expansion foam and conventional sprays in a low-speed horizontal wind tunnel under controlled environmental conditions. Dimensions of the tunnel were 1.30 m high, 0.61 m wide, and 7.32 m long. Wind speed was maintained at 1.52 m/sec. Drift was compared for spray solutions, with and without foam adjuvants, using several different types and sizes of air-inducting nozzles and three sizes of conventional fan nozzles. Large drops produced by the air-inducting nozzles, with and without foam adjuvant, resulted in significantly less drift beyond 1.83 and 6.10 m than sprays from the conventional fan nozzles. The addition of foam adjuvant to the spray solution resulted in increased drift beyond 1.83 m for sprays from the air-induction nozzles in several comparisons but did not result in a significant increase in the drift beyond 6.10 m.