ASTM E2798-19

Standard Test Method for Characterization of Performance of Pesticide Spray Drift Reduction Adjuvants for Ground Application

SIGNIFICANCE AND USE
5.1 Pesticide regulations for the minimization of drift during pesticide application often require active ingredient (a.i.) product use under defined droplet size conditions. Spray performance with respect to transport and deposition of droplets and particles at target surfaces and product efficacy for desired applications are also affected by droplet size spectra. The effect of drift reduction adjuvants on droplet size spectra should be understood in this context. The present test method describes standard tests that can be conducted to investigate the performance of pesticide spray drift reduction adjuvants under simulated field use conditions for drift management decisions in the context of the entire spraying process. The measured reduction in driftable fines and shift in spray droplet size distribution can be used to reduce the buffer zones mandated by regulatory agencies.
SCOPE
1.1 This test method is used to characterize the performance of pesticide spray drift reduction adjuvants with respect to spray droplet size spectra, volume of fines, and other use parameters under simulated field ground application conditions. This test method does not include any procedures to evaluate if pump shear degrades the performance of the spray drift reduction adjuvant.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
Note 1: This method uses industry-standard units. The following conversions to SI units are provided for convenience: 1 mph = 1.61 kph; 1 in = 2.54 cm; 1 gal/acre = 9.36 L/hectare.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2019
• ICS: 65.100.01 - Pesticides and other agrochemicals in general
• Technical Committee: E35 - Pesticides, Antimicrobials, and Alternative Control Agents
• Drafting Committee: E35.22 - Pesticide Formulations and Delivery Systems

Relations

• Replaces: ASTM E2798-11 - Standard Test Method for Characterization of Performance of Pesticide Spray Drift Reduction Adjuvants for Ground Application
• Effective Date: 01-Oct-2019
• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM E799-03(2020)e1 - Standard Practice for Determining Data Criteria and Processing for Liquid Drop Size Analysis
• Effective Date: 01-Apr-2020
• Refers: ASTM E1260-03(2020) - Standard Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering Instruments
• Effective Date: 01-Apr-2020
• Refers: ASTM E456-13A(2017)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM E456-13A(2017)e3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM E609-16 - Standard Terminology Relating to Pesticides
• Effective Date: 15-Sep-2016
• Refers: ASTM E1519-15b - Standard Terminology Relating to Agricultural Tank Mix Adjuvants
• Effective Date: 01-Oct-2015
• Refers: ASTM E1519-15a - Standard Terminology Relating to Agricultural Tank Mix Adjuvants
• Effective Date: 01-Aug-2015
• Refers: ASTM E1519-15 - Standard Terminology Relating to Agricultural Tank Mix Adjuvants
• Effective Date: 01-Jun-2015
• Refers: ASTM E609-15a - Standard Terminology Relating to Pesticides
• Effective Date: 01-May-2015
• Refers: ASTM E799-03(2015) - Standard Practice for Determining Data Criteria and Processing for Liquid Drop Size Analysis
• Effective Date: 01-Mar-2015
• Refers: ASTM E1260-03(2015) - Standard Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering Instruments
• Effective Date: 01-Mar-2015
• Refers: ASTM E609-15 - Standard Terminology Relating to Pesticides
• Effective Date: 01-Jan-2015
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014

Overview

ASTM E2798-19: Standard Test Method for Characterization of Performance of Pesticide Spray Drift Reduction Adjuvants for Ground Application is an internationally recognized method developed by ASTM International. This standard outlines procedures to evaluate the performance of pesticide spray drift reduction adjuvants (DRAs) during ground application under simulated field conditions. Adjuvants that effectively reduce the volume of driftable spray droplets can significantly minimize unintended pesticide deposition, enhance application efficacy, support regulatory compliance, and reduce environmental impacts.

By characterizing spray droplet size spectra and associated drift potential, this method assists manufacturers, applicators, and regulators in making informed decisions about DRA selection, tank mix compatibility, and drift management strategies.

Key Topics

• Spray Drift and Pesticide Application: Regulatory bodies require minimized pesticide drift to protect off-target areas. Droplet size spectra are central to drift potential and application efficiency.
• Drift Reduction Adjuvants Assessment: The standard details laboratory protocols for evaluating how specific adjuvants affect droplet formation and distribution during ground application.
• Simulated Field Conditions: Testing is conducted using spray chambers or wind tunnels to replicate real-world scenarios and ensure relevant, credible data.
• Measurement Techniques: The method employs advanced droplet size analysis using laser diffraction, phase Doppler analyzers, and imaging systems.
• Safety and Environmental Considerations: The standard addresses health, safety, and environmental practices for laboratory handling, disposal, and testing with reference to applicable regulations.

Applications

ASTM E2798-19 provides practical value in several contexts:

• Product Development and Registration: Pesticide and adjuvant manufacturers can demonstrate the drift reduction efficacy of their products to satisfy regulatory requirements.
• Regulatory Compliance: Data from this test method can be used to support reduced buffer zone requirements by proving superior drift control performance, streamlining pesticide approvals and use directions.
• Tank Mix Optimization: Applicators and agronomists benefit by selecting and validating compatible adjuvant-active ingredient combinations that optimize spray quality and coverage while limiting drift.
• Operator and Environmental Safety: By quantifying and managing drift, applicators help protect sensitive habitats, water resources, and human health.
• Research and Comparative Analysis: Laboratories and research organizations use this standardized protocol to compare the relative performance of different drift reduction technologies under controlled conditions.

Related Standards

ASTM E2798-19 references and aligns with several international and industry-specific standards for spray drift and droplet analysis:

• ASTM E799: Practice for determining data criteria and processing for liquid drop size analysis.
• ASTM E1260: Test Method for determining liquid drop size characteristics in a spray using optical nonimaging light-scattering instruments.
• ASTM E2408: Test Method for measuring relative extensional viscosity of agricultural spray tank mixes.
• ASABE/ANSI S572.2: Spray nozzle classification by droplet spectra.
• NFPA 30 and NFPA 33: Standards for safe handling and application of flammable liquids and spray processes.
• ASTM E456, E609, E1519, and E1620: Terminologies related to pesticides, tank mix adjuvants, liquid particles, and atomization.

These related standards support comprehensive, harmonized approaches to evaluating drift management practices and adjuvant performance.

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Keywords: pesticide spray drift, drift reduction adjuvants, ASTM E2798-19, droplet size spectrum, ground application, tank mix, drift control, spray performance, regulatory compliance, buffer zones, spray chamber, wind tunnel.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2798 − 19
Standard Test Method for
Characterization of Performance of Pesticide Spray Drift
Reduction Adjuvants for Ground Application
This standard is issued under the fixed designation E2798; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
1.1 This test method is used to characterize the performance
E456 Terminology Relating to Quality and Statistics
of pesticide spray drift reduction adjuvants with respect to
E609 Terminology Relating to Pesticides
spray droplet size spectra, volume of fines, and other use
E799 Practice for Determining Data Criteria and Processing
parameters under simulated field ground application condi-
for Liquid Drop Size Analysis
tions. This test method does not include any procedures to
E1260 Test Method for Determining Liquid Drop Size
evaluate if pump shear degrades the performance of the spray
Characteristics in a Spray Using Optical Nonimaging
drift reduction adjuvant.
Light-Scattering Instruments
1.2 The values stated in SI units are to be regarded as
E1519 Terminology Relating to Agricultural Tank Mix Ad-
standard. No other units of measurement are included in this
juvants
standard.
E1620 Terminology Relating to Liquid Particles andAtomi-
zation
NOTE 1—This method uses industry-standard units. The following
conversions to SI units are provided for convenience: 1 mph = 1.61 kph; E2408 Test Method for Relative Extensional Viscosity of
1 in = 2.54 cm; 1 gal/acre = 9.36 L/hectare.
Agricultural Spray Tank Mixes
1.3 This standard does not purport to address all of the
2.2 ASABE Standards:
safety concerns, if any, associated with its use. It is the
ANSI/ASAE S572.2 Spray Nozzle Classification by Droplet
responsibility of the user of this standard to establish appro-
Spectra, July 2018
priate safety, health, and environmental practices and deter-
2.3 NFPA Standards:
mine the applicability of regulatory limitations prior to use.
NFPA 30 Flammable and Combustible Liquids Code
1.4 This international standard was developed in accor-
NFPA 33 Standard for Spray Application Using Flammable
dance with internationally recognized principles on standard-
or Combustible Materials
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3. Terminology
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. 3.1 Definitions for terms used in this test method can be
found in Terminologies E456, E609, E1519, and E1620.
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
D3825 Test Method for Dynamic Surface Tension by the
4.1 This test method provides guidelines for the measure-
Fast-Bubble Technique (Withdrawn 2016)
ment of parameters pertaining to the performance of drift
reduction adjuvants under simulated field ground application
1 conditions.The measurements can be made in a wind tunnel or
This test method is under the jurisdiction of ASTM Committee E35 on
Pesticides, Antimicrobials, and Alternative Control Agents and is the direct spray chamber. The method describes the preparation,
responsibility of Subcommittee E35.22 on Pesticide Formulations and Delivery
composition, and test/application conditions for droplet size
Systems.
and spray pattern measurements. Exact selection of application
Current edition approved Oct. 1, 2019. Published December 2019. Originally
conditions, such as nozzle type and tank mix partners, may
approved in 2011. Last previous edition approved in 2011 as E2798–11.
DOI:10:1520/E2798–19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American Society of Agricultural and Biological Engineers
the ASTM website. (ASABE), 2950 Niles Rd., St. Joseph, MI 49085, http://www.asabe.org.
3 5
The last approved version of this historical standard is referenced on Available from National Fire Protection Association (NFPA), 1 Batterymarch
www.astm.org. Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2798 − 19
varyaccordingtointendeduseconditions.Thistestmethodhas diffraction analysis. Test Method E1260 outlines the procedure
not been verified for aerial and orchard airblast pesticide for determining liquid drop size using these instruments.
applications.
6.3 Liquid preparation and delivery system, including agi-
tation mechanism for tank mixes.
5. Significance and Use
6.4 Nozzle and spray application system for ground appli-
5.1 Pesticideregulationsfortheminimizationofdriftduring
cation platforms.
pesticide application often require active ingredient (a.i.)
product use under defined droplet size conditions. Spray
7. Hazards
performance with respect to transport and deposition of drop-
7.1 SafetyPrecautions—Before testing, read the precaution-
lets and particles at target surfaces and product efficacy for
ary statements on the product label, and the Material Safety
desired applications are also affected by droplet size spectra.
Data Sheet, or both. Take proper precautions to prevent skin
The effect of drift reduction adjuvants on droplet size spectra
contact and inhalation of the fines, or the vapors, or both. Take
should be understood in this context. The present test method
care to prevent contamination of the surrounding area.Always
describesstandardteststhatcanbeconductedtoinvestigatethe
wear the appropriate safety equipment and, where indicated,
performance of pesticide spray drift reduction adjuvants under
wear respiratory devices approved by NIOSH for the product
simulated field use conditions for drift management decisions
being tested.
in the context of the entire spraying process. The measured
7.1.1 Warning—A spray of flammable liquid dispersed in
reduction in driftable fines and shift in spray droplet size
air presents the risk of explosion and fire. Refer to NFPA30 or
distributioncanbeusedtoreducethebufferzonesmandatedby
NFPA 33 for information about safe practices for storage and
regulatory agencies.
handling of flammable liquids and for spray processes involv-
6. Apparatus ing sprays of flammable liquids.
7.1.2 Warning—Exposure to drops of various liquids by
6.1 Spray chamber or wind tunnel of known air flow
inhalation, ingestion, and skin contact may constitute health
characteristics. Droplet size measurements may be made in a
hazards.
spray chamber or wind tunnel. Where a spray chamber is used
7.1.3 Warning—Emission of some sprayed liquids into the
for simulating ground application of pesticides, make provi-
atmosphere may be harmful to the environment or may pose a
sionstohaveanairflowwithaminimum7mphvelocityinthe
health risk.
direction of the sprayed fluid. The Spray Drift Task Force
7.1.4 Warning—Laser-based instruments contain lasers or
(http://www.spraydrift.com) has found that this minimum air
other strong light sources which may pose a hazard to persons
flow will keep the small drops moving forward and prevent
in their vicinity.
them from swirling back and getting measured multiple times.
7.2 Contain all sprayed material and be sure to dispose of
Adiagram of an example test arrangement can be seen in Fig.
1 of Test Method E1260, but locate the exhaust vent at the this material and remaining test substances properly.
bottom of the spray chamber so the ambient air is moving in
8. Selection of Test Substances
the same direction as the sprayed fluid.Where a wind tunnel is
used for simulating ground applications of pesticides, size the 8.1 Selecttestsubstancesthatreflecttheintendedend-useof
wind tunnel working section width to allow the spray to fully the drift reduction adjuvant. While water can provide a useful
form without constriction. The minimum width for normal use
baseline for range-finding tests, it must not be the sole system
with a wide range of nozzle and atomizer types will be 1 m. tested. Use the active ingredient pesticide formulation spray
The height shall be sufficient to allow a full traverse (using
tank mixture as one of the test substances with the adjuvant.
either continuous or chordal measurement sampling) through For example, commercial herbicides may be selected for
the entire spray cross-section. Usually this will require a
adjuvants intended for use in herbicide applications. The use
minimum height of 1 m. rate for the tests shall reflect commercial label use rates. It may
be desirable to select several test substances for the
6.2 Droplet size analyzer with calibration verification for
evaluations, to compare performance between products. It may
tests. The droplet size analyzer selected for the tests shall be
be appropriate to include other adjuvants such as surfactants,
appropriate for the type of measurement being conducted and
crop oils, or fertilizers, as the label allows. For example,
have a dynamic size range configuration capable of measuring
ammonium sulfate (AMS) is recommended on many pesticide
the entire droplet size range produced by the sprays under
levels. Compatibility agents will be included if necessary to
investigation. Appropriate techniques include, but are not
create a physically stable system.
limited to, laser diffraction, Phase-Doppler particle size ana-
6 7
lyzers and imaging systems. Sympatec and Malvern make 8.2 Where possible, measure the physical properties of the
instrumentscapableofmeasuringspraydropletsizeusinglaser test substance, particularly the dynamic surface tension at a
6 7
The sole source of supply of the apparatus known to the committee at this time The sole source of supply of the apparatus known to the committee at this time
isSympatecGmbH,System-Partikel-Technik,AmPulverhaus1D-38678Clausthal- is Malvern Instruments Ltd, Enigma Business Park, Grovewood Road, Malvern,
Zellerfeld, Germany. If you are aware of alternative suppliers, please provide this Worcestershire WR14 1XZ, United Kingdom. If you are aware of alternative
information to ASTM International Headquarters. Your comments will receive suppliers, please provide this information to ASTM International Headquarters.
careful consideration at a meeting of the responsible technical committee, which Your comments will receive careful consideration at a meeting of the responsible
you may attend. technical committee, which you may attend.
E2798 − 19
surfacelifetimeageof20ms,shearandextensionalviscosities. usually involve an airstream velocity up to 18 mph to facilitate
Test Method D3825 provides a technique for measuring sampling with number density sampling techniques.
dynamic surface tension. Test Method E2408 provides a
10.2 Ground Spraying Systems—For ground-based
technique for measuring extensional viscosity.
applications, ANSI/ASAE S572.2 provides flat fan reference
8.3 Use WHO 342 ppm hardness water in all sample
nozzles of different designations between extremely fine (XF)
preparations.
and ultra coarse (UC).These are often used in standard droplet
size tests in Europe, NorthAmerica, and other regions. Include
9. Preparation of Test Substances
the reference sprays to assess whether the adjuvants cause the
9.1 Mixing Order—Mix the test substance components in
sprays to shift toward finer or coarser sprays. The extremely
themannerdescribedintheirrespectivemixinginstructions.In
fine category is not commonly used in agricultural sprays. The
some cases, this may involve the preparation of a pre-mix of
actual test nozzle will be specified by the adjuvant
adjuvant(s) and active ingredient formulation. The samples
manufacturer, but may include one or more of the following
must be mixed until homogeneous. Compatibility agents must
nozzle types for ground-based application tests at typical
be added to mixtures that do not form physically stable
recommended use conditions: flat fan, air induction, and cone.
samples.
If possible, include nozzles of at least two initial droplet size
classes. Table 1 provides examples of test and reference
10. Nozzles, Atomizers, and Spraying System
nozzle/pressure combinations that are used in ground applica-
10.1 Nozzle Types and Use Conditions—The nozzle selec-
tions. All use a 50 mesh screen to prevent plugging and all
tionwilldependontheintendedend-usefortheadjuvantunder
yield about 0.2 gpm flow at the same given pressure listed in
evaluation. Section 10.2 lists resources for nozzles which
Table 1.
should be used at a minimum for the tests, depending on
applicationtypes.Additionalnozzletypesandusepatternsmay
11. Procedure
also be included if appropriate for the pesticide and use type.
The performance of many adjuvants depends on the nozzle
11.1 Droplet Size Measurement—Data criteria and process-
typeanduseconditions,aswellastheinitialdropletsizerange.
ing examples are given in Practice E799. The droplet size
For example, some adjuvants may cause an increase in the
analyzer shall be used in accordance with appropriate ASTM/
coarseness of the spray for sprays which are initially relatively
ISO standard test methods. Methods for using laser diffraction
fine, or for certain types of nozzle, while providing different
instruments are given in Test Methods E1260.
behavior with sprays of different initial (that is, no adjuvant)
11.1.1 Precision—Refer to Practice E177.
conditions. Ground nozzles are usually operated at pressures
11.1.2 Droplet Size—Droplets shall be measured and char-
around 40 psig.The exact pressure for a given test will depend
acterized using an instrument having demonstrated accuracy in
on manufacturer recommended operating conditions and test
the range of droplet size produced by the nozzle being tested.
requirements. Measure and record the effect of the adjuvant on
spray pressure and liquid flow rate. Ground applications The instrument shall have a calibration verification performed
TABLE 1 Test and Reference Spray Quality Nozzle
Recommendations
Nozzle
B
Pressure
Spraying Lechler
Application Spray Quality
Systems (psig)
A
TeeJet
Adjuvant Drift Fine XR11002 LU11002 40.0
Reduction Medium to Coarse TT11002 AD11002 40.0
Test Nozzles Coarse to Very Coarse AIXR11002 IDK11002 40.0
Very Course to Extra AI11002 ID11002 40.0
Coarse
ANSI/ASAE Very Fine/Fine XR11001 . 65.3
S572.2 Fine/Medium XR11003 . 43.5
Spray Quality Medium/Coarse XR11006 . 29.0
Reference Coarse/Very Coarse XR8008 . 36.3
Nozzles Very Coarse/Extra Coarse TP6510 . 2.9
Extra Coarse/Ultracoarse TP6515 . 21.7
A
The sole source of supply of the apparatus known t
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2798 − 11 E2798 − 19
Standard Test Method for
Characterization of Performance of Pesticide Spray Drift
Reduction Adjuvants for Ground Application
This standard is issued under the fixed designation E2798; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method is used to characterize the performance of pesticide spray drift reduction adjuvants with respect to spray
droplet size spectra, volume of fines, and other use parameters under simulated field ground application conditions. This test
method does not include any procedures to evaluate if pump shear degrades the performance of the spray drift reduction adjuvant.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
NOTE 1—This method uses industry-standard units. The following conversions to SI units are provided for convenience: 1 mph = 1.61 kph; 1 in = 2.54
cm; 1 gal/acre = 9.36 L/hectare.
1.3 This test method does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D3825 Test Method for Dynamic Surface Tension by the Fast-Bubble Technique (Withdrawn 2016)
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E609 Terminology Relating to Pesticides
E799 Practice for Determining Data Criteria and Processing for Liquid Drop Size Analysis
E1260 Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering
Instruments
E1519 Terminology Relating to Agricultural Tank Mix Adjuvants
E1620 Terminology Relating to Liquid Particles and Atomization
E2408 Test Method for Relative Extensional Viscosity of Agricultural Spray Tank Mixes
2.2 ASABE Standards:
ASAE S572.1ANSI/ASAE S572.2 Spray Nozzle Classification by Droplet Spectra, March 2009July 2018
2.3 NFPA Standards:
NFPA 30 Flammable and Combustible Liquids Code
NFPA 33 Standard for Spray Application Using Flammable or Combustible Materials
This test method is under the jurisdiction of ASTM Committee E35 on Pesticides, Antimicrobials, and Alternative Control Agents and is the direct responsibility of
Subcommittee E35.22 on Pesticide Formulations and Delivery Systems.
Current edition approved Jan. 1, 2011Oct. 1, 2019. Published February 2011December 2019. DOI:10:1520/E2798–11.Originally approved in 2011. Last previous edition
approved in 2011 as E2798–11. DOI:10:1520/E2798–19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from American Society of Agricultural and Biological Engineers (ASABE), 2950 Niles Rd., St. Joseph, MI 49085, http://www.asabe.org.
Available from National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2798 − 19
3. Terminology
3.1 Definitions for terms used in this test method can be found in Terminologies E456, E609, E1519, and E1620.
4. Summary of Test Method
4.1 This test method provides guidelines for the measurement of parameters pertaining to the performance of drift reduction
adjuvants under simulated field ground application conditions. The measurements can be made in a wind tunnel or spray chamber.
The method describes the preparation, composition, and test/application conditions for droplet size and spray pattern
measurements. Exact selection of application conditions, such as nozzle type and tank mix partners, may vary according to
intended use conditions. This test method has not been verified for aerial and orchard airblast pesticide applications.
5. Significance and Use
5.1 Pesticide regulations for the minimization of drift during pesticide application often require active ingredient (a.i.) product
use under defined droplet size conditions. Spray performance with respect to transport and deposition of droplets and particles at
target surfaces and product efficacy for desired applications are also affected by droplet size spectra. The effect of drift reduction
adjuvants on droplet size spectra should be understood in this context. The present test method describes standard tests that can
be conducted to investigate the performance of pesticide spray drift reduction adjuvants under simulated field use conditions for
drift management decisions in the context of the entire spraying process. The measured reduction in driftable fines and shift in
spray droplet size distribution can be used to reduce the buffer zones mandated by regulatory agencies.
6. Apparatus
6.1 Spray chamber or wind tunnel of known air flow characteristics. Droplet size measurements may be made in a spray
chamber or wind tunnel. Where a spray chamber is used for simulating ground application of pesticides, make provisions to have
an air flow with a minimum 7 mph velocity in the direction of the sprayed fluid. The Spray Drift Task Force (http://
www.spraydrift.com) has found that this minimum air flow will keep the small drops moving forward and prevent them from
swirling back and getting measured multiple times. A diagram of an example test arrangement can be seen in Fig. 1 of Test Method
E1260, but locate the exhaust vent at the bottom of the spray chamber so the ambient air is moving in the same direction as the
sprayed fluid. Where a wind tunnel is used for simulating ground applications of pesticides, size the wind tunnel working section
width to allow the spray to fully form without constriction. The minimum width for normal use with a wide range of nozzle and
atomizer types will be 1 m. The height shall be sufficient to allow a full traverse (using either continuous or chordal measurement
sampling) through the entire spray cross-section. Usually this will require a minimum height of 1 m.
6.2 Droplet size analyzer with calibration verification for tests. The droplet size analyzer selected for the tests shall be
appropriate for the type of measurement being conducted and have a dynamic size range configuration capable of measuring the
entire droplet size range produced by the sprays under investigation. Appropriate techniques include, but are not limited to, laser
6 7
diffraction, Phase-Doppler particle size analyzers and imaging systems. Sympatec and Malvern make instruments capable of
measuring spray droplet size using laser diffraction analysis. Test Method E1260 outlines the procedure for determining liquid drop
size using these instruments.
6.3 Liquid preparation and delivery system, including agitation mechanism for tank mixes.
6.4 Nozzle and spray application system for ground application platforms.
7. Hazards
7.1 Safety Precautions—Before testing, read the precautionary statements on the product label, and the Material Safety Data
Sheet, or both. Take proper precautions to prevent skin contact and inhalation of the fines, or the vapors, or both. Take care to
prevent contamination of the surrounding area. Always wear the appropriate safety equipment and, where indicated, wear
respiratory devices approved by NIOSH for the product being tested.
7.1.1 Warning—A spray of flammable liquid dispersed in air presents the risk of explosion and fire. Refer to NFPA 30 or NFPA
33 for information about safe practices for storage and handling of flammable liquids and for spray processes involving sprays of
flammable liquids.
7.1.2 Warning—Exposure to drops of various liquids by inhalation, ingestion, and skin contact may constitute health hazards.
7.1.3 Warning—Emission of some sprayed liquids into the atmosphere may be harmful to the environment or may pose a
health risk.
The sole source of supply of the apparatus known to the committee at this time is Sympatec GmbH, System-Partikel-Technik, Am Pulverhaus 1 D-38678
Clausthal-Zellerfeld, Germany. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive
careful consideration at a meeting of the responsible technical committee, which you may attend.
The sole source of supply of the apparatus known to the committee at this time is Malvern Instruments Ltd, Enigma Business Park, Grovewood Road, Malvern,
Worcestershire WR14 1XZ, United Kingdom. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments
will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
E2798 − 19
7.1.4 Warning—Laser-based instruments contain lasers or other strong light sources which may pose a hazard to persons in
their vicinity.
7.2 Contain all sprayed material and be sure to dispose of this material and remaining test substances properly.
8. Selection of Test Substances
8.1 Select test substances that reflect the intended end-use of the drift reduction adjuvant. While water can provide a useful
baseline for range-finding tests, it must not be the sole system tested. Use the active ingredient pesticide formulation spray tank
mixture as one of the test substances with the adjuvant. For example, commercial herbicides may be selected for adjuvants intended
for use in herbicide applications. The use rate for the tests shall reflect commercial label use rates. It may be desirable to select
several test substances for the evaluations, to compare performance between products. It may be appropriate to include other
adjuvants such as surfactants, crop oils, or fertilizers, as the label allows. For example, ammonium sulfate (AMS) is recommended
on many pesticide levels. Compatibility agents will be included if necessary to create a physically stable system.
8.2 Where possible, measure the physical properties of the test substance, particularly the dynamic surface tension at a surface
lifetime age of 20 ms, shear and extensional viscosities. Test Method D3825 provides a technique for measuring dynamic surface
tension. Test Method E2408 provides a technique for measuring extensional viscosity.
8.3 Use WHO 342 ppm hardness water in all sample preparations.
9. Preparation of Test Substances
9.1 Mixing Order—Mix the test substance components in the manner described in their respective mixing instructions. In some
cases, this may involve the preparation of a pre-mix of adjuvant(s) and active ingredient formulation. The samples must be mixed
until homogeneous. Compatibility agents must be added to mixtures that do not form physically stable samples.
10. Nozzles, Atomizers, and Spraying System
10.1 Nozzle Types and Use Conditions—The nozzle selection will depend on the intended end-use for the adjuvant under
evaluation. Section 10.2 lists resources for nozzles which should be used at a minimum for the tests, depending on application
types. Additional nozzle types and use patterns may also be included if appropriate for the pesticide and use type. The performance
of many adjuvants depends on the nozzle type and use conditions, as well as the initial droplet size range. For example, some
adjuvants may cause an increase in the coarseness of the spray for sprays which are initially relatively fine, or for certain types
of nozzle, while providing different behavior with sprays of different initial (that is, no adjuvant) conditions. Ground nozzles are
usually operated at pressures around 40 psig. The exact pressure for a given test will depend on manufacturer recommended
operating conditions and test requirements. Measure and record the effect of the adjuvant on spray pressure and liquid flow rate.
Ground applications usually involve an airstream velocity up to 18 mph to facilitate sampling with number density sampling
techniques.
10.2 Ground Spraying Systems—For ground-based applications, ASAE S572.1ANSI/ASAE S572.2 provides flat fan reference
nozzles of different designations between extremely fine (XF) and ultra coarse (UC). These are often used in standard droplet size
tests in Europe, North America, and other regions. Include the reference sprays for the boundaries between fine/medium and
medium/coarse sprays (which cover most commercial arable spray applications) to assess whether the adjuvants cause the sprays
to shift toward finer or coarser sprays. If the desired test nozzle produces a coarser spray quality, then also include the reference
nozzles for the coarse/very coarse and very coarse/ultra coarse boundaries. The The extremely fine category is not commonly used
in agricultural sprays. The actual test nozzle will be specified by the adjuvant manufacturer, but may include one or more of the
following nozzle types for ground-based application tests at typical recommended use conditions: flat fan, air induction, and cone.
If possible, include nozzles of at least two initial droplet size classes. Table 1 provides examples of test and reference
nozzle/pressure combinations that are used in ground applications. All use a 50 mesh screen to prevent plugging and all yield about
0.2 gpm flow at the same given pressure.pressure listed in Table 1.
11. Procedure
11.1 Droplet Size Measurement—Data criteria and processing examples are given in Practice E799. The droplet size analyzer
shall be used in accordance with appropriate ASTM/ISO standard test methods. Methods for using laser diffraction instruments are
given in Test Methods E1260.
11.1.1 Precision—Refer to Practice E177.
11.1.2 Droplet Size—Droplets shall be measured and characterized using an instrument having demonstrated accuracy in the
range of droplet size produced by the nozzle being tested. The instrument shall have a calibration verification performed with a
known source of droplets or other method. An alternative method would be to measure reference particles in a liquid suspension,
as supplied by the instrument manufacturer.
11.1.3 Volume Density Weighted (Spatial) Sampling Type Droplet Measuring Device—Measurements can be made with a
forward-light scattering (also called diffraction) instrument, imaging system, or other number density-weighted sampling
technique. Spray measurements shall be co
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