ASTM D6980-17

Standard Test Method for Determination of Moisture in Plastics by Loss in Weight

SIGNIFICANCE AND USE
5.1 This test method is intended for use as a control, acceptance, and assessment test.  
5.2 Moisture will affect the processability of some materials. For these materials, defects will occur if they are processed with a moisture content outside of the recommended range.  
5.3 The physical properties of some plastics are greatly affected by the moisture content.
SCOPE
1.1 This test method covers the quantitative determination of moisture by means of loss in weight technology down to 50 mg/kg (50 ppm) as it applies to most plastics.  
1.2 The values stated in SI units are to be regarded as the standard.  
1.3 Specimens tested by this method will be hot, use caution when handling them after testing has been completed.  
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.
Note 1: There is no known ISO equivalent to this standard.  
1.5 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: 14-Jun-2017
• ICS: 83.080.01 - Plastics in general
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Relations

• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM D883-20 - Standard Terminology Relating to Plastics
• Effective Date: 01-Jan-2020
• Refers: ASTM D883-19c - Standard Terminology Relating to Plastics
• Effective Date: 01-Aug-2019
• Refers: ASTM D883-19a - Standard Terminology Relating to Plastics
• Effective Date: 15-Apr-2019
• Refers: ASTM D883-19 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2019
• Refers: ASTM D883-18a - Standard Terminology Relating to Plastics
• Effective Date: 01-Dec-2018
• Refers: ASTM D883-18 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2018
• Refers: ASTM D1600-18 - Standard Terminology for Abbreviated Terms Relating to Plastics (Withdrawn 2024)
• Effective Date: 01-Jan-2018
• Refers: ASTM E2935-17 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Oct-2017
• Refers: ASTM D883-17 - Standard Terminology Relating to Plastics
• Effective Date: 15-Aug-2017
• Refers: ASTM E2935-16 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 15-Nov-2016
• Refers: ASTM E2935-15 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Oct-2015
• Refers: ASTM E2935-14 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Oct-2014
• Refers: ASTM D1600-14 - Standard Terminology for Abbreviated Terms Relating to Plastics
• Effective Date: 01-Feb-2014

Overview

ASTM D6980-17: Standard Test Method for Determination of Moisture in Plastics by Loss in Weight is an internationally recognized ASTM standard that provides a quantitative method for determining moisture content in plastic materials. Using loss in weight technology, the method can detect moisture levels down to 50 mg/kg (50 ppm), making it highly sensitive and suitable for a wide range of plastics.

This standard is essential for process control, acceptance testing, and quality assessment within the plastics industry. By establishing a consistent, reliable approach to moisture determination, ASTM D6980-17 supports manufacturers and laboratories in maintaining the required quality and performance of plastic products.

Key Topics

• Moisture Determination by Loss in Weight: The standard outlines the procedure for using a moisture analyzer, involving weighing a plastic sample, heating it to vaporize moisture, and measuring the resulting weight loss.
• Sensitive Measurement Range: Capable of reliably detecting moisture concentrations as low as 50 mg/kg (50 ppm), suitable for most plastics in pellet, powder, or granule form.
• Control and Quality Assurance: The method serves as a control, acceptance, and assessment tool, helping ensure materials meet processability and regulatory requirements.
• Calibration and Verification: Instructions are provided for calibrating the analyzer with NIST-traceable weights and temperature standards to maintain accuracy.
• Interferences: Guidance is provided to minimize error from evolved volatiles or decomposition products that may bias results.
• Safety Considerations: Cautions regarding handling hot specimens and laboratory safety are included, emphasizing risk assessment and best practices.

Applications

The moisture content of plastics has a significant impact on product quality and manufacturing outcomes. Following ASTM D6980-17, industries can:

• Production Control: Monitor and control moisture levels to prevent defects such as bubbles, voids, and brittle parts in molded or extruded plastics.
• Raw Material Assessment: Evaluate the quality of incoming plastic resins by verifying they are within specified moisture limits before processing.
• Material Acceptance: Approve or reject plastic shipments based on precise moisture measurement, reducing risk of downstream failures.
• Physical Property Validation: Correlate moisture content with mechanical and thermal properties to ensure desired product performance.
• Research and Development: Characterize new materials or optimize formulations by systematically varying and measuring moisture content.
• Compliance: Demonstrate adherence to ASTM quality control procedures and support traceability in audits and validation projects.

Industries that can benefit include automotive, packaging, electronics, medical devices, consumer goods, and any sector relying on plastic component performance.

Related Standards

ASTM D6980-17 references and complements several other important standards for plastics testing and moisture analysis:

• ASTM D883: Terminology Relating to Plastics
• ASTM D1600: Terminology for Abbreviated Terms Relating to Plastics
• ASTM D6869: Test Method for Coulometric and Volumetric Determination of Moisture in Plastics Using the Karl Fischer Reaction
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ASTM E2935: Practice for Conducting Equivalence Testing in Laboratory Applications

Notably, there is no ISO equivalent to ASTM D6980-17, making it the definitive guidance for loss in weight moisture analysis of plastics on a global scale.

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Keywords: ASTM D6980-17, moisture determination in plastics, loss in weight method, plastics quality control, moisture analysis, calibration, ASTM standards, polymer testing, plastic material assessment, manufacturing process control.

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: D6980 − 17
Standard Test Method for
Determination of Moisture in Plastics by Loss in Weight
This standard is issued under the fixed designation D6980; 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* 3. Terminology
1.1 This test method covers the quantitative determination 3.1 Definitions—The definitions used in this test method are
of moisture by means of loss in weight technology down to 50 in accordance with Terminologies D883 and D1600.
mg/kg (50 ppm) as it applies to most plastics.
3.2 Symbols:
1.2 The values stated in SI units are to be regarded as the 3.2.1 lift—the result of convection currents created during
standard. the heating of the specimen raising the sample pan off of its
support falsely indicating a moisture loss.
1.3 Specimenstestedbythismethodwillbehot,usecaution
3.2.1.1 Discussion—The effects of lift are compensated for
when handling them after testing has been completed.
in different ways by different manufacturers.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 The specimen is spread onto a sample pan that is
priate safety and health practices and determine the applica-
supported on a balance in a heating chamber that has been
bility of regulatory limitations prior to use.
preheated and equilibrated to the specified idle temperature. It
NOTE 1—There is no known ISO equivalent to this standard.
is then heated to vaporize the moisture. The analysis is
completed when the indicated weight loss falls below a rate
1.5 This international standard was developed in accor-
specified in the test conditions. The total loss of weight is
dance with internationally recognized principles on standard-
integrated and displayed as the percent of moisture.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4.2 Through adjustment of the analyzer’s parameter
mendations issued by the World Trade Organization Technical
settings, a set of conditions is developed to measure moisture.
Barriers to Trade (TBT) Committee.
5. Significance and Use
2. Referenced Documents
5.1 This test method is intended for use as a control,
2.1 ASTM Standards:
acceptance, and assessment test.
D883 Terminology Relating to Plastics
5.2 Moisture will affect the processability of some materi-
D1600 Terminology forAbbreviatedTerms Relating to Plas-
als. For these materials, defects will occur if they are processed
tics
with a moisture content outside of the recommended range.
D6869 Test Method for Coulometric and Volumetric Deter-
5.3 The physical properties of some plastics are greatly
mination of Moisture in Plastics Using the Karl Fischer
affected by the moisture content.
Reaction (the Reaction of Iodine with Water)
E691 Practice for Conducting an Interlaboratory Study to
6. Interferences
Determine the Precision of a Test Method
E2935 Practice for Conducting Equivalence Testing in
6.1 When testing plastic materials for moisture by a loss in
Laboratory Applications weight technique, the possibility exists for volatiles other than
moisture to be evolved and cause a biased high result if the
material has not been dried to remove excess moisture and low
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
boiling volatiles. It is important to have a working knowledge
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
of the material that is being tested and to remain below any
Current edition approved June 15, 2017. Published August 2017. Originally
melting or decomposition temperatures that would unnecessar-
approved in 2004. Last previous edition approved in 2012 as D6980 - 12. DOI:
10.1520/D6980-17. ily cause the emission of volatiles which can be harmful.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
7. Apparatus
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 7.1 Moisture Analyzer, containing:
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6980 − 17
7.1.1 The capability of the oven shall be selected based 10.1.3 Begin the program and follow the prompts for
upon the specific material being tested. Suggested test tem- placing the sample on the sample pan.
peratures for specific plastics are shown in Tables A1.1-A3.1. 10.1.4 At the end of the test allow the analyzer to cool (if
standby heating is not enabled) and remove the sample pan.
NOTE 2—It will be necessary to contact the analyzer manufacturer for
10.1.5 Record the result as displayed in percent moisture.
suggested test temperatures for materials not listed in Tables A1.1-A3.1.
10.1.6 Place a clean sample pan in the analyzer and allow
7.1.2 A balance capable of measuring to 0.0001 g.
equilibration prior to beginning subsequent tests.
7.1.3 An electronic or mechanical means of compensating
10.2 Determination of Optimal Test Conditions:
for lift caused by convection currents created during testing.
7.1.4 A processor that is capable of converting the loss of
NOTE 4—When determining the optimal test conditions for a material,
weight to digital data.
it is useful to have a Karl Fischer apparatus available and test in
accordance withTest Method D6869 or contact the analyzer manufacturer
7.1.5 Digital display for presenting the digital data as
who in some cases will provide this service for you.
percent moisture.
7.1.6 Sample Pans, made from “0” temper,Aluminum 3003 10.2.1 Program the analyzer in accordance with the condi-
or other nonreactive material. tions listed in Annex A1, Annex A2,or Annex A3.
10.2.2 To determine the optimum test temperature for a
8. Test Specimen and Sample
material, run a single test which includes several consecutive
programs that have been linked together. Each program is
8.1 Due to the small specimen size, exercise care to ensure
identical in its parameters except the temperature is increased
that the specimen is representative of the sample.
5°C.
8.2 Due to the hygroscopic nature of many plastics, samples
NOTE 5—When increasing the test temperature, do not exceed a
shall be stored in airtight containers made of glass or other
temperature where the potential exists for the emission of harmful fumes.
qualified or suitable material.
NOTE 6—Ensure that the program selected to run first is the lowest
8.3 Samples that have been heated to remove moisture prior temperature.
to processing and testing shall be allowed to cool to room
10.2.3 After the tests have completed, plot the result versus
temperature in a sealed container prior to determination.
temperature to make a curve as in Fig. 1.
10.2.3.1 Most of the moisture is vaporized in temperature
8.4 Test specimens in the form of powders, pellets, or
range from points 1 to 3.
ground material.
10.2.3.2 Between points 3 and 5 the moisture result is very
9. Calibration and Standardization low and constant. Choose a temperature in this range as the
optimum test temperature.
9.1 To maintain the integrity of the test results the balance
10.2.3.3 Above point 5 the moisture result begins to in-
and heater shall both be calibrated using a traceable standard.
crease. This is likely caused by the generation of water due to
9.2 The calibration is verified using sodium tartrate dihy-
decomposition or solid phase polymerization of the sample.
drate exhibiting a known crystal water content of 15.66 % with
NOTE 7—It is not uncommon for the optimal test temperature to be
an acceptable result range of 15.61 to 15.71 %. Other materials
above the melting point of the selected plastic due to the distance between
with verifiable theoretical water content are acceptable for
the resistive thermal device and the sample pan.
validation.
11. Calculation
9.3 Prepare the analyzer for use and perform the analysis as
described in 10.1. 11.1 Result is reported in percent moisture to three decimal
places so no further calculations are necessary.
9.4 If the result is not within the acceptable range, return to
9.3 for re-analysis. 11.2 If conversion to mg/kg is desired, calculate as follows:
mg/kg 5 Moisture content ~%! 310000 (1)
9.5 If results are still not within the acceptable range, first
perform a temperature calibration and then a balance calibra-
12. Report
tion to ensure analyzer performance. Retest with sodium
12.1 Report the following information:
tartrate dihydrate. If results still are not within the acceptable
range, the cause of the nonconformance must be determined
and corrected before proceeding with testing.
10. Procedure
10.1 Sample Analysis:
10.1.1 Prepare analyzer as suggested by instrument manu-
facturer.
10.1.2 Program the analyzer with the suggested test condi-
tions listed in Annex A1, Annex A2,or Annex A3.
NOTE3—IftestconditionsforaspecificmaterialarenotlistedinAnnex
A1, AnnexA2,or AnnexA3, they will have to be determined experimen-
tally or by contacting the analyzer manufacturer. FIG. 1 Optimum Test Temperature Selection
D6980 − 17
TABLE 1 Moisture (%)
A
Average Standard Repeatability Reproducibility Repeatability Reproducibility
Deviation of Standard Standard Limit Limit
Material
Lab Averages Deviation Deviation
x¯S s s rR
r R
A (Nylon 6/6) 0.4954 0.0131 0.0086 0.0151 0.0242 0.0423
B (PET) 0.0292 0.0084 0.0047 0.0094 0.0133 0.0263
C (TPE) 0.0107 0.0070 0.0026 0.0073 0.0072 0.0204
D (PC) 0.0748 0.0040 0.0061 0.0067 0.0171 0.0187
E (Nylon 6/6) 0.1390 0.0302 0.0241 0.0367 0.0674 0.1027
F (TPE) 0.0406 0.0329 0.0024 0.0330 0.0068 0.09
...

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: D6980 − 12 D6980 − 17
Standard Test Method for
Determination of Moisture in Plastics by Loss in Weight
This standard is issued under the fixed designation D6980; 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 Scope*
1.1 This test method covers the quantitative determination of moisture by means of loss in weight technology down to 50 mg/kg
(50 ppm) as it applies to most plastics.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 Specimens tested by this method will be hot, use caution when handling them after testing has been completed.
1.4 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 and health practices and determine the applicability of regulatory
limitations prior to use.
NOTE 1—There is no known ISO equivalent to this standard.
1.5 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:
D883 Terminology Relating to Plastics
D1600 Terminology for Abbreviated Terms Relating to Plastics
D6869 Test Method for Coulometric and Volumetric Determination of Moisture in Plastics Using the Karl Fischer Reaction (the
Reaction of Iodine with Water)
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2935 Practice for Conducting Equivalence Testing in Laboratory Applications
3. Terminology
3.1 Definitions—The definitions used in this test method are in accordance with Terminologies D883 and D1600.
3.2 Symbols:
3.2.1 lift—the result of convection currents created during the heating of the specimen raising the sample pan off of its support
falsely indicating a moisture loss.
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Feb. 1, 2012June 15, 2017. Published March 2012August 2017. Originally approved in 2004. Last previous edition approved in 20092012 as
D6980 - 09.D6980 - 12. DOI: 10.1520/D6980-12.10.1520/D6980-17.
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.
3.2.1.1 Discussion—
The effects of lift are compensated for in different ways by different manufacturers.
3.2.2 tempering—a process that re-defines the molecular structure of a metal to enhance its performance.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6980 − 17
4. Summary of Test Method
4.1 The specimen is spread onto a sample pan that is supported on a balance in a heating chamber that has been preheated and
equilibrated to the specified idle temperature. It is then heated to vaporize the moisture. The analysis is completed when the
indicated weight loss falls below a rate specified in the test conditions. The total loss of weight is integrated and displayed as the
percent of moisture. Both the analyzer’s balance and heater are calibrated to NIST standards to achieve precise and accurate results.
4.2 Through adjustment of the analyzer’s parameter settings, a set of conditions is developed to measure moisture.
5. Significance and Use
5.1 This test method is intended for use as a control, acceptance, and assessment test.
5.2 Moisture will affect the processability of some materials. For these materials, defects will occur if they are processed with
a moisture content outside of the recommended range.
5.3 The physical properties of some plastics are greatly affected by the moisture content.
6. Interferences
6.1 When testing plastic materials for moisture by a loss in weight technique, the possibility exists for volatiles other than
moisture to be evolved and cause a biased high result if the material has not been dried to remove excess moisture and low boiling
volatiles. It is important to have a working knowledge of the material that is being tested and to remain below any melting or
decomposition temperatures that would unnecessarily cause the emission of volatiles which can be harmful.
7. Apparatus
7.1 Moisture Analyzer, containing:
7.1.1 The capability of the oven shall be selected based upon the specific material being tested. Suggested test temperatures for
specific plastics are shown in Tables A1.1 and A1.1-A2.1A3.1.
NOTE 2—It will be necessary to contact the analyzer manufacturer for suggested test temperatures for materials not listed in Tables A1.1 and
A1.1-A2.1A3.1.
7.1.2 A balance capable of measuring to 0.0001 g.
7.1.3 An electronic or mechanical means of compensating for lift caused by convection currents created during testing.
7.1.4 A processor that is capable of converting the loss of weight to digital data.
7.1.5 Digital display for presenting the digital data as percent moisture.
7.1.6 Sample Pans, made from “0” temper, Aluminum 3003 or other nonreactive material.
8. Test Specimen and Sample
8.1 Due to the small specimen size, exercise care to ensure that the specimen is representative of the sample.
8.2 Due to the hygroscopic nature of many plastics, samples shall be stored in airtight containers made of glass or other qualified
or suitable material.
8.3 Samples that have been heated to remove moisture prior to processing and testing shall be allowed to cool to room
temperature in a sealed container prior to determination.
8.4 Test specimens in the form of powders, pellets, or ground material.
9. Calibration and Standardization
9.1 To maintain the integrity of the test results the balance and heater shall both be calibrated using NIST-traceable weights and
an NIST-traceable temperature calibration interface.a traceable standard.
9.2 The calibration is verified using sodium tartrate dihydrate exhibiting a known crystal water content of 15.66 % with an
acceptable result range of 15.61 to 15.71 %. Other materials with verifiable theoretical water content are acceptable for validation.
9.3 Prepare the analyzer for use and perform the analysis as described in 10.1.
9.4 If the result is not within the acceptable range, return to 9.3 for re-analysis.
9.5 If results are still not within the acceptable range, first perform a temperature calibration and then a balance calibration to
ensure analyzer performance. Retest with sodium tartrate dihydrate. If results still are not within the acceptable range, the cause
of the nonconformance must be determined and corrected before proceeding with testing.
10. Procedure
10.1 Sample Analysis:
10.1.1 Prepare analyzer as suggested by instrument manufacturer.
10.1.2 Program the analyzer with the suggested test conditions listed in Annex A1, Annex A2, or Annex A3.
D6980 − 17
NOTE 3—If test conditions for a specific material are not listed in Annex A1, Annex A2, or Annex A3, they will have to be determined experimentally
or by contacting the analyzer manufacturer.
10.1.3 Begin the program and follow the prompts for placing the sample on the sample pan.
10.1.4 At the end of the test allow the analyzer to cool (if standby heating is not enabled) and remove the sample pan.
10.1.5 Record the result as displayed in percent moisture.
10.1.6 Place a clean sample pan in the analyzer and allow equilibration prior to beginning subsequent tests.
10.2 Determination of Optimal Test Conditions:
NOTE 4—When determining the optimal test conditions for a material, it is useful to have a Karl Fischer apparatus available and test in accordance
with Test Method D6869 or contact the analyzer manufacturer who in some cases will provide this service for you.
10.2.1 Program the analyzer in accordance with the conditions listed in Annex A1, Annex A2or , or Annex A2A3.
10.2.2 To determine the optimum test temperature for a material, run a single test which includes several consecutive programs
that have been linked together. Each program is identical in its parameters except the temperature is increased 5°.5°C.
NOTE 5—When increasing the test temperature, do not exceed a temperature where the potential exists for the emission of harmful fumes.
NOTE 6—Ensure that the program selected to run first is the lowest temperature.
10.2.3 After the tests have completed, plot the result versus temperature to make a curve as in Fig. 1.
10.2.3.1 Most of the moisture is vaporized in temperature range from points 1 to 3.
10.2.3.2 Between points 3 and 5 the moisture result is very low and constant. Choose a temperature in this range as the optimum
test temperature.
10.2.3.3 Above point 5 the moisture result begins to increase. This is likely caused by the generation of water due to
decomposition or solid phase polymerization of the sample.
NOTE 7—It is not uncommon for the optimal test temperature to be above the melting point of the selected plastic due to the distance between the
resistive thermal device and the sample pan.
11. Calculation
11.1 Result is reported in percent moisture to three decimal places so no further calculations are necessary.
11.2 If conversion to mg/kg is desired, calculate as follows:
mg/kg 5 Moisture content ~%!310000 (1)
12. Report
12.1 Report the following information:
12.1.1 Complete identification of the sample tested, including type of material, source, manufacturer’s code, form, and previous
history,
12.1.2 Date of test,
12.1.3 Individual specimen size,
12.1.4 Individual specimen moisture, and
12.1.5 Average moisture if multiple tests are run.
3,4
13. Precision and Bias
13.1 The precisionrepeatability of this test method is based on an interlaboratory study conducted in 2007. Eight laboratories
analyzed eight different plastic materials for moisture content. Every “test result” represents an individual determination. The
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D20-1250.
Equivalence testing in ASTM standards are covered by Practice E2935.
FIG. 1 Optimum Test Temperature Selection
D6980 − 17
TABLE 1 Moisture (%)
A
Average Standard Repeatability Reproducibility Repeatability Reproducibility
Deviation of Standard Standard Limit Limit
Material
Lab Averages Deviation Deviation
x¯ Sx¯ s s r R
r R
x¯ S s s r R
r R
A (Nylon 6/6) 0.4954 0.0131 0.0086 0.0151 0.0242 0.0423
B (PET) 0.0292 0.0084 0.0047 0.0094 0.0133 0.0263
C (TPE) 0.0107 0.0070 0.0026 0.0073 0.0072 0.0204
D (PC) 0.0748 0.0040 0.0061 0.0067 0.0171 0.0187
E (Nylon 6/6) 0.1390 0.0302 0.0241 0.0367 0.0674 0.1027
F (TPE) 0.0406 0.0329 0.0024 0.0330 0.0068 0.0924
G (PC) 0.0181 0.0085 0.0030 0.0088
...