Under the proposed US EPA Drift Reduction Technology (DRT) protocols, low speed wind tunnel testing can be used to define drift reduction potential for a given application technology. However, as the program is currently envisioned, emphasis has been placed upon equipment-based DRTs such as nozzles and shielded/shrouded spray booms. For chemistry-derived DRTs such as tank adjuvants, and, especially, formulation-based solutions, it is unclear how the drift reduction potential can be derived without significant field-scale testing. A test case will be described that suggests that wind tunnel-measures of the fraction of fine particles produced by a nozzle-formulation combination can be a successful surrogate for drift reduction and subsequently, a DRT rating. Results from a replicated operational-scale field study will be shown that strongly correlate with the fraction of driftable fines produced with the same nozzle-formulation combination. It will be proposed that the resulting correlations can then be used to extrapolate low-cost wind tunnel results to field-scale DRT ratings for chemistry-based drift reduction systems.

Validation of the extrapolation of wind tunnel-generated spray droplet distributions to DRT classifications with field data

246th National Meeting (2013)

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