2. Spray Droplet Size Standard S-572 Robert E. Wolf Extension Specialist Application Technology Biological and Agricultural Engineering

3. Efficacy and Drift Potential is Influenced by Size of the Spray Droplets - Volume Median Diameter (VMD) Droplet Spectrum (Range - big to small) % Volume in droplets less than 200 microns in size

4. One micron (  m ) =1/25,000 inch Relationship of Drift to Drop Size

5. Comparison of Micron Sizes for Various Items: (approximate values) pencil lead 2000 (  m ) paper clip 850 (  m ) staple 420 (  m ) toothbrush bristle 300 (  m ) sewing thread150 (  m ) human hair100 (  m ) 150

6. 1/2 of spray volume = larger droplets VMD 1/2 of spray volume = smaller droplets

7. Cutting Droplet Size in Half Results in Eight Times the Number of Droplets 500 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns

8. Important Droplet Statistics Operational Area

9. Evaporation of Droplets Wind High Relative Humidity Low Temperature Low Relative Humidity High Temperature Fall Distance

10. Example Reference Graph Cumulative Volume Fraction 0.10.50.9 Drop Size (microns) 0 100 200 300 400 500 600 700 800 900 very fine/ fine fine/medium medium/ coarse coarse/ very coarse very coarse/ extremely coarse VF F M C VC XC Guidance to Chemical Manufacturers Match the crop protection product to the target Adhere to label guidelines based on an industry standard ASAE S-572 Buffer Zones or No Spray Zones Maximize Efficacy Minimize Drift EPA Requested Changes Coming !?!?

11. ASAE S-572 Droplet Size Standard

12. Origin Of Standardized Spray Droplet Size Categories 1985 -- British Crop Protection Council (BCPC) Droplet size classifications, primarily designed to enhance efficacy. Uses the term SPRAY QUALITY for droplet size categories. 2000 -- ASAE Standard S572 Droplet size classifications, primarily designed to control spray drift. Uses the term DROPLET SPECTRA CLASSIFICATION for droplet size categories.

13. Specifics of the Standard Based on spraying water through reference nozzles. Nozzle manufacturers can conduct the tests. Must use a set of reference tips and a laser- based instrument. Droplet Spectra measurements must be with the same: Instrument, measuring method, sampling technique, scanning technique, operator, and in a similar environmental condition.

15. Coverage Need knowledge of the product being used. Systemic Contact What is the target? Soil Grass Broadleaf (smooth, hairy, waxy) Leaf orientation – time of day

16. ASAE DSC and Volume Median Diameter (D V0.5 ) From PMS* Laser Spectrometer Very Fine (VF) < 182µm Fine (F)183-280µm Medium (M)281-429µm Coarse (C)430-531µm Very Coarse (VC) 532-655µm Extremely Coarse (XC) >656µm *USDA ARS College Station, TX Droplet Spectra Classification (DSC) Droplet Size Range

17. Nozzle Technology? How to use?? Nozzles designed to reduce drift Improved drop size control Emphasis on ‘Spray Quality’

18. Spray Characteristics are Important to Understand: Demonstrates Turbo Flat vs TurboDrop-5 MPH Wind

19. Nozzles Types?

20. Extended Range Flat-fan: Tapered edge pattern 80 and 110 degree fan Requires overlap - 50 to 60% 15-60 psi range

21. Extended Range Flat-fan: Tapered edge pattern 80 and 110 degree fan Requires overlap - 50 to 60% 15-60 psi range 110° 80°

22. Demo

23. Nozzles Types?

24. Turbo Flat-fan: l Turbulence chamber as in the Turbo Flood l Tapered edge, wide angle flat pattern l Designed to work in flat-fan nozzle holder l Uniform spray distribution, 50-60% overlap l Wide pressure range, 15 – 90 psi l Large, drift resistant droplets l Plastic with superior wear characteristics

25. Turbo Flat-fan: l Turbulence chamber as in the Turbo Flood l Tapered edge, wide angle flat pattern l Designed to work in flat-fan nozzle holder l Uniform spray distribution, 50-60% overlap l Wide pressure range, 15 – 90 psi l Large, drift resistant droplets l Plastic with superior wear characteristics TT XR

26. Demo

27. Nozzles Types?

28. Air-Induction/Venturi Nozzles Where air is drawn into the nozzle cavity and exits with the fluid.

29. Air/Induction – Venturi Nozzle: Spraying Systems AI TeeJet Air intake venturi section Mixing Chamber - air and spray solution blended Exit orifice - Pattern tip - forms large air-bubble drops Better Penetration? Reduced run-off? Improved coverage? Adequate efficacy? Reduced drift? YES!!!

30. XR Flat-fan and Turbo Flat-fan compared to Venturi Style 5.0 MPH wind at 40 psi XR vs TurboDropTurbo Flat vs Turbo Drop

31. Demo

32. Driftable Droplets: Spraying Systems-2000 Nozzle Type (0.5 GPM Flow) Approximate % of Spray Volume < 200 Microns 15 PSI40 PSI XR 1100514%22% XR 80056%12% DG 11005N/A11% DG 8005N/A7% TT 11005<1%<6% TF-2.5<1% AI 11005N/A<1%

34. Page 4

35. Computer Models:

36. AgDRIFT® Program Map

37. Example of Model Use – Aerial Applicators Standard Operation

38. For more information contact: www.bae.ksu.edu/rewolf/ rewolf@ksu.edu