ASTM E2408-04(2023)

Standard Test Method for Relative Extensional Viscosity of Agricultural Spray Tank Mixes

SIGNIFICANCE AND USE
4.1 Extensional viscosity is a measure of the resistance of a liquid to stretching forces, such as those occurring during the disruption of liquid films and the formation of sprays used in agriculture and other purposes including painting operations or metal working. This method for measurement of a Screen Factor, gives a relative value for extensional viscosity, which may be used:  
4.1.1 To compare the potential for drift control of different polymers.  
4.1.2 To compare the relative extensional viscosity component of different spray tank mixtures.  
4.1.3 To determine the extent of breakdown of polymer solutions used as drift control additives during the recirculation of the solutions through pumps and screens.  
4.1.4 To use as a parameter in the Spray Drift Task Force Models for droplet size prediction.  
4.2 It should also be noted that many drift control polymers are irreversibly destroyed during the recirculation of spray mixes by pumping with high shear pumps such as gear or centrifugal pumps. It is advisable to subject the test mixture to similar pumping regimes to simulate practical conditions before carrying out the extensional viscosity test. Measurements of extensional viscosity are the only presently known method of determining the extent of this breakdown properties of dilute polymer solutions.  
4.3 This method is intended to produce a relative value for extensional viscosity. The purpose of the method is to compare the extensional viscosity produced by different polymer types or concentrations of polymer in spray tank mixes.
SCOPE
1.1 This test method covers the determination of the relative extensional viscosity or Screen Factor (SF) of dilute agricultural spray mixes.  
1.2 The test can be used for tank mixes containing dissolved, emulsified or dispersed materials, or mixtures.  
1.3 Results may be affected by the quality of the water used. Make-up water quality should therefore be specified in the presentation of results.  
1.4 Proper safety and hygiene precautions must be taken when working with pesticide formulations to prevent skin or eye contact, vapor inhalation, and environmental contamination. Read and follow all handling instructions for the specific formulation and conduct the test in accordance with good laboratory practice.
Note 1: References to the development of extensional viscosity from dissolved polymers, extensional viscosity effects on the droplet size distribution of sprays, and measurements of screen factor on recirculated spray mixes containing polymers are available.2,3  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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.  
1.7 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: 31-May-2023
• ICS: 17.060 - Measurement of volume, mass, density, viscosity
• Technical Committee: E35 - Pesticides, Antimicrobials, and Alternative Control Agents
• Drafting Committee: E35.22 - Pesticide Formulations and Delivery Systems

Relations

• Refers: ASTM E1116-98(2019) - Standard Test Method for Emulsification Characteristics of Pesticide Emulsifiable Concentrates
• Effective Date: 01-Oct-2019
• Refers: ASTM E609-16 - Standard Terminology Relating to Pesticides
• Effective Date: 15-Sep-2016
• Refers: ASTM E609-15a - Standard Terminology Relating to Pesticides
• Effective Date: 01-May-2015
• Refers: ASTM E609-15 - Standard Terminology Relating to Pesticides
• Effective Date: 01-Jan-2015
• Refers: ASTM E1116-98(2014) - Standard Test Method for Emulsification Characteristics of Pesticide Emulsifiable Concentrates
• Effective Date: 01-Oct-2014
• Refers: ASTM E609-10 - Standard Terminology Relating to Pesticides
• Effective Date: 01-Mar-2010
• Refers: ASTM E1116-98(2008) - Standard Test Method for Emulsification Characteristics of Pesticide Emulsifiable Concentrates
• Effective Date: 01-Oct-2008
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM E609-05 - Standard Terminology Relating to Pesticides
• Effective Date: 01-Apr-2005
• Refers: ASTM E609-04 - Standard Terminology Relating to Pesticides
• Effective Date: 01-Nov-2004
• Refers: ASTM E609-03a - Standard Terminology Relating to Pesticides
• Effective Date: 01-Oct-2003
• Refers: ASTM E1116-98(2002) - Standard Test Method for Emulsification Characteristics of Pesticide Emulsifiable Concentrates
• Effective Date: 10-Oct-2002
• Refers: ASTM E609-03 - Standard Terminology Relating to Pesticides
• Effective Date: 10-Oct-2002
• Refers: ASTM E609-02a - Standard Terminology Relating to Pesticides
• Effective Date: 10-Oct-2002
• Refers: ASTM E609-02 - Standard Terminology Relating to Pesticides
• Effective Date: 10-Apr-2001

Overview

ASTM E2408-04(2023): Standard Test Method for Relative Extensional Viscosity of Agricultural Spray Tank Mixes provides a reliable method for determining the relative extensional viscosity, also known as the Screen Factor (SF), of dilute agricultural spray tank mixtures. Developed under the auspices of ASTM International, this standard is essential for assessing the resistance of liquids-particularly those containing polymers-to stretching forces, which directly impacts spray applications in agriculture, as well as other industries such as painting and metalworking.

The test method primarily uses a screen viscometer to measure and compare the extensional viscosity of different spray formulations and additives, particularly those used for drift control. This is important for predicting spray droplet sizes, ensuring effective application, and minimizing environmental impact due to spray drift.

Key Topics

• Extensional Viscosity: Measurement of a liquid’s resistance to stretching forces, which is a key factor in spray formation and performance.
• Screen Factor (SF): Relative value calculated as the ratio of the efflux time of the test fluid to that of water through a specific screen viscometer.
• Spray Tank Mixes: Applies to mixtures containing dissolved, emulsified, or dispersed materials, including additives for drift control.
• Polymer Breakdown: Evaluates the impact of recirculation and mechanical shear (such as by pumps) on the integrity and performance of drift control polymers.
• Water Quality: Influence of water chemistry and purity on viscosity measurements, requiring specification in reported results.
• Good Laboratory Practice: Emphasis on safety, health, and environmental considerations when handling pesticide-containing solutions.

Applications

ASTM E2408-04(2023) is widely used in agricultural research, formulation development, and quality control laboratories for several key purposes:

• Drift Control Comparison: Enables the comparison of different polymers or additives for their effectiveness in reducing spray drift through improved extensional viscosity.
• Spray Tank Mix Optimization: Assists in selecting or formulating tank mixes to optimize droplet size and application efficiency.
• Polymer Stability Assessment: Detects the extent of breakdown or degradation of polymer-based drift control agents during pump recirculation, simulating real-world spray application conditions.
• Model Parameterization: Provides critical input to Spray Drift Task Force Models used for predicting spray droplet size distributions.
• Cross-industry Usage: Applicable beyond agriculture, including in painting operations, metalworking, and any process involving spray application where the viscosity characteristics of dilute fluids are crucial.

By accurately comparing the screen factor of different formulations or processing treatments, users can ensure better application performance, regulatory compliance, and environmental protection.

Related Standards

When implementing ASTM E2408-04(2023), the following related standards and references may also be relevant:

• ASTM D1193: Specification for Reagent Water, highlights the importance of water quality in test reproducibility.
• ASTM E609: Terminology Relating to Pesticides, providing definitions essential for understanding and consistency.
• ASTM E1116: Test Method for Emulsification Characteristics of Pesticide Emulsifiable Concentrates, which may be used in conjunction for comprehensive spray characterization.
• CIPAC Monograph 1 and Methods MT 18.1.1–18.1.7: Instructions for preparation of standard waters commonly referenced in international pesticide testing.

Proper application of ASTM E2408-04(2023) supports best practices in formulation development, tank mix evaluation, and regulatory compliance, making it an indispensable tool in modern agricultural and industrial spray application systems.

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: E2408 − 04 (Reapproved 2023)
Standard Test Method for
Relative Extensional Viscosity of Agricultural Spray Tank
Mixes
This standard is issued under the fixed designation E2408; 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 Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This test method covers the determination of the relative
Barriers to Trade (TBT) Committee.
extensional viscosity or Screen Factor (SF) of dilute agricul-
tural spray mixes.
2. Referenced Documents
1.2 The test can be used for tank mixes containing
2.1 ASTM Standards:
dissolved, emulsified or dispersed materials, or mixtures.
D1193 Specification for Reagent Water
1.3 Results may be affected by the quality of the water used.
E609 Terminology Relating to Pesticides
Make-up water quality should therefore be specified in the
E1116 Test Method for Emulsification Characteristics of
presentation of results.
Pesticide Emulsifiable Concentrates
1.4 Proper safety and hygiene precautions must be taken
2.2 CIPAC Documents:
when working with pesticide formulations to prevent skin or
CIPAC Monograph 1 (Instructions for the preparation of
eye contact, vapor inhalation, and environmental contamina-
hard water)
tion. Read and follow all handling instructions for the specific
CIPAC Method MT 18.1.1 to 18.1.7 (Instructions for the
formulation and conduct the test in accordance with good
preparation of standard waters)
laboratory practice.
3. Terminology
NOTE 1—References to the development of extensional viscosity from
dissolved polymers, extensional viscosity effects on the droplet size
3.1 Definitions:
distribution of sprays, and measurements of screen factor on recirculated
3.1.1 extensional viscosity, (E)—a measure of the resistance
2,3
spray mixes containing polymers are available.
of a fluid to distortion by a stretching force.
1.5 The values stated in SI units are to be regarded as
3.1.2 screen factor, (SF)—the ratio of the flow time of a test
standard. No other units of measurement are included in this
fluid (t ) to the flow time of water (t ) through the screen
p w
standard.
viscometer apparatus.
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Significance and Use
responsibility of the user of this standard to establish appro-
4.1 Extensional viscosity is a measure of the resistance of a
priate safety, health, and environmental practices and deter-
liquid to stretching forces, such as those occurring during the
mine the applicability of regulatory limitations prior to use.
disruption of liquid films and the formation of sprays used in
1.7 This international standard was developed in accor-
agriculture and other purposes including painting operations or
dance with internationally recognized principles on standard-
metal working. This method for measurement of a Screen
ization established in the Decision on Principles for the
Factor, gives a relative value for extensional viscosity, which
may be used:
This test method is under the jurisdiction of ASTM Committee E35 on
4.1.1 To compare the potential for drift control of different
Pesticides, Antimicrobials, and Alternative Control Agentsand is the direct respon-
polymers.
sibility of Subcommittee E35.22 on Pesticide Formulations and Delivery Systems.
4.1.2 To compare the relative extensional viscosity compo-
Current edition approved June 1, 2023. Published July 2023. Originally approved
in 2004. Last previous edition approved in 2015 as E2408 – 04 (2015). DOI: nent of different spray tank mixtures.
10.1520/E2408-04R23.
Dexter, R. W.,“Measurements of Extensional Viscosity of Polymer Solutions
and its Effect on Atomization from a Spray Nozzle,” Atomization and Sprays, Vol
6, 1996, pp. 167–191 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Zhu, H., Dexter, R. W., Fox, R. D., Reichard, D. L., Brazee, R. D., and Okzan, contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
H. E.,“Droplet Size and Viscosity Effects in Recirculated Polymer Spray Solutions,” Standards volume information, refer to the standard’s Document Summary page on
J. Agric. Engr. Res., Vol 67, 1997, pp. 35–45 the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2408 − 04 (2023)
4.1.3 To determine the extent of breakdown of polymer 5.1.5 Item 5—Glass tube, cut from a 2 mL pipette, Kimax
solutions used as drift control additives during the recirculation #37000, or equivalent (American Scientific catalog #P4140-2).
of the solutions through pumps and screens. Dimensions of tube are: length = 3 cm; outside diameter = 0.62
4.1.4 To use as a parameter in the Spray Drift Task Force cm. Round off the sharp ends of the tube in a flame.
Models for droplet size prediction.
NOTE 2—Appropriate safety precautions should be taken when using an
4.2 It should also be noted that many drift control polymers
open flame for rounding the ends of the glass tubes.
are irreversibly destroyed during the recirculation of spray
5.2 Assembly of Screen Viscometer—Refer to Fig. 1, which
mixes by pumping with high shear pumps such as gear or
shows the arrangement of the separate items of equipment, and
centrifugal pumps. It is advisable to subject the test mixture to
Fig. 2, which shows the placement of the screen pack in the
similar pumping regimes to simulate practical conditions
plastic union.
before carrying out the extensional viscosity test. Measure-
5.2.1 Push the five stainless screen discs, one at a time, into
ments of extensional viscosity are the only presently known
the ⁄4 in. (0.635 cm) plastic union. Push each screen down to
method of determining the extent of this breakdown properties
the central lug in the union, using a piece of ⁄4 in. glass tubing.
of dilute polymer solutions.
Ensure that the last of the 5 screens fits tightly into the plastic
4.3 This method is intended to produce a relative value for
tube to keep the pack of screens well compacted and fixed in
extensional viscosity. The purpose of the method is to compare
place.
the extensional viscosity produced by different polymer types
5.2.2 Push the silicone rubber sleeve (Item 4) on to the
or concentrations of polymer in spray tank mixes.
lower end of the pipette tube (Item 3). Leave approximately 0.8
5. Apparatus cm of the silicone tube projecting beyond the glass.
5.2.3 Push the short glass tube (Item 5) into the plastic union
5.1 List of Materials for Construction of Screen Viscometer:
1 firmly and press down on the pack of screens. Screw on the end
5.1.1 Item 1—Fluorinated plastic ⁄4 in. (0.635 cm) straight
cap of the union to retain the position of the screen pack.
union, reference SKU-II4, P#D1O77019. Norton Performance
Ensure that the Teflon cone supplied with the union is fitted
Plastics, 150 Dey Road, Wayne, New Jersey, 07470, USA.
1 properly, to provide a leak tight seal. About 0.6 cm of the glass
5.1.2 Item 2—Cut five (5) ⁄4 in. diameter discs (see 5.2)
tube should protrude from the end cap of the union.
from 100 mesh (150 μm aperture) USA Standard Testing Sieve,
5.2.4 Push together the glass tube protruding from the end
ASTM E11 specification, stainless steel plain weave screen, so
as to fit tightly into the ⁄4 in. plastic union. cap, into the silicone rubber sleeve attached to the pipette.
Check the alignment of the pipette and screen pack for
5.1.3 Item 3—Glass 25 mL pipette, {VWR catalog #7102
(1999)} or equivalent. External diameter of the tube below the straightness.
...