ASTM E398-03

Standard Test Method for Water Vapor Transmission Rate of Sheet Materials Using Dynamic Relative Humidity Measurement

SIGNIFICANCE AND USE
No single set of test conditions can represent all climatic and use conditions, so this WVTR test method serves more to compare different materials at a stated set of conditions than to predict their actual performance in the field under any conditions.
The water vapor transmission rate, under known and carefully controlled conditions, may be used to evaluate the vapor barrier qualities of a sheet. Direct correlation of values obtained under different conditions of test temperature and relative humidity will be valid provided the barrier material under test does not undergo changes in solid state (such as a crystalline transition or melting point) at or between the conditions of test.
SCOPE
1.1 This test method covers dynamic evaluation of the rate of transfer of water vapor through a flexible barrier material and allows conversion to the generally recognized units of water vapor transmission (WVT) as obtained by various other test methods including the gravimetric method described in Test Methods E 96.
1.2 LimitationsThis test method is limited to flexible barrier sheet materials composed of either completely hydrophobic materials, or combinations of hydrophobic and hydrophilic materials having at least one surface that is hydrophobic.
1.3 The minimum test value obtained by this test method is limited by the leakage of water vapor past the clamping seals of the test instrument. A reasonable value may be approximately 0.01 g/24 hm 2 for any WVTR method including the desiccant procedure of Test Methods E 96 at 37.8C (100F), and 90 % relative humidity. This limit can be checked for each instrument with an impervious specimen such as aluminum foil. Calibration procedures can compensate for the leakage rate if so stated.
1.4 This test method is not suitable for referee testing at this time, but is suitable for control testing and material comparison.
1.5 The values stated in SI units are to be regarded as standard. The values gives in parentheses are provided for information purposes only.
1.6 Several other ASTM test methods are available to test a similar property. This test method is unique in that it closely duplicates typical product storage where a transfer of moisture from a package into the environment is allowed to proceed without constantly sweeping the environmental side with dry gas. Methods with constantly swept dry sides include Test Methods F 1249, ASTM F 372, and ASTM F 1770.
1.7 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.

General Information

• Status: Historical
• Publication Date: 09-May-2003
• Technical Committee: F02 - Primary Barrier Packaging
• Drafting Committee: F02.10 - Permeation

Relations

• Replaced By: ASTM E398-03(2009)e1 - Standard Test Method for Water Vapor Transmission Rate of Sheet Materials Using Dynamic Relative Humidity Measurement
• Effective Date: 01-May-2009
• Referred By: ASTM E3069-19a - Standard Guide for Evaluation and Rehabilitation of Mass Masonry Walls for Changes to Thermal and Moisture Properties of the Wall
• Effective Date: 10-May-2003
• Referred By: ASTM E3127-22 - Standard Guide for Specifying Water Vapor Transmission Material Properties of Water-Resistive Barriers and Air Barriers
• Effective Date: 10-May-2003
• Referred By: ASTM F2902-16e1 - Standard Guide for Assessment of Absorbable Polymeric Implants
• Effective Date: 10-May-2003
• Referred By: ASTM F2097-20 - Standard Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products
• Effective Date: 10-May-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E398–03
Standard Test Method for
Water Vapor Transmission Rate of Sheet Materials Using
Dynamic Relative Humidity Measurement
This standard is issued under the fixed designation E 398; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers dynamic evaluation of the rate
responsibility of the user of this standard to establish appro-
of transfer of water vapor through a flexible barrier material
priate safety and health practices and determine the applica-
and allows conversion to the generally recognized units of
bility of regulatory limitations prior to use.
water vapor transmission (WVT) as obtained by various other
test methods including the gravimetric method described in
2. Referenced Documents
Test Methods E 96.
2.1 ASTM Standards:
1.2 Limitations—This test method is limited to flexible
C 168 Terminology Relating to Thermal Insulation
barrier sheet materials composed of either completely hydro-
C 677 Practice for Use of a Polyethylene Terephthalate
phobic materials, or combinations of hydrophobic and hydro-
Reference Film for the Measurement of the Time-
philic materials having at least one surface that is hydrophobic.
Averaged Vapor Pressure in a Controlled Humidity Space
1.3 The minimum test value obtained by this test method is
E 96/E 96M Test Methods for Water Vapor Transmission of
limited by the leakage of water vapor past the clamping seals
Materials
of the test instrument. A reasonable value may be approxi-
F17 Terminology Relating to Flexible Barrier Materials
mately 0.01 g/24 h·m for any WVTR method including the
F 372 Test Method for Water Vapor Transmission Rate of
desiccant procedure of Test Methods E 96 at 37.8°C (100°F),
Flexible Barrier Materials Using an Infrared Detection
and 90 % relative humidity. This limit can be checked for each
Technique
instrument with an impervious specimen such as aluminum
F 1249 Test Method for Water Vapor Transmission Rate
foil. Calibration procedures can compensate for the leakage
Through Plastic Film and Sheeting Using a Modulated
rate if so stated.
Infrared Sensor
1.4 This test method is not suitable for referee testing at this
F 1770 Test Method for Evaluation of Solubility, Diffusiv-
time, but is suitable for control testing and material compari-
ity, and Permeability of Flexible Barrier Materials toWater
son.
Vapor
1.5 The values stated in SI units are to be regarded as
standard. The values gives in parentheses are provided for
3. Terminology
information purposes only.
3.1 Definitions—For definitions of terms concerning the
1.6 Several otherASTM test methods are available to test a
transmission of water vapor refer to Terminologies C 168 and
similar property. This test method is unique in that it closely
F17.
duplicates typical product storage where a transfer of moisture
from a package into the environment is allowed to proceed
4. Summary of Test Method
without constantly sweeping the environmental side with dry
4.1 Thespecimenismountedbetweentwochambers,oneof
gas. Methods with constantly swept dry sides include Test
relatively high relative humidity and the other of relatively low
Methods F 1249, ASTM F 372, and ASTM F 1770.
relative humidity. After conditioning and isolation of cham-
bers, the rate at which the moisture increases within the
This test method is under the jurisdiction ofASTM Committee F02 on Flexible
Barrier Materials and is the direct responsibility of Subcommittee F02.10 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Permeation. A previous version was under the jurisdiction of ASTM Committee contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
C16. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved May 10, 2003. Published July 2003. Originally the ASTM website.
approved in 1970. Discontinued in 1994 and reinstated as E 398–03. Withdrawn.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E398–03
relatively low relative humidity chamber over a predetermined the specimen and yet no direct contact. Other levels of relative
range of interest is measured. This rate is compared to the rate humidity may be obtained with saturated salt solutions or a
for a calibration sample (calibrated gravimetrically) and the stream of controlled humidified air.
WVTR is determined. 6.1.4 Air Source—Air dried below the operating humidity
FIG. 1 Sectional Diagram of a Typical Test Chamber Using Relative Humidity Sensing
5. Significance and Use range of the instrument (5 % relative humidity or less) shall be
used as a purge for the sensor-side chamber.Various desiccants
5.1 Nosinglesetoftestconditionscanrepresentallclimatic
have been found satisfactory as drying agents.
and use conditions, so this WVTR test method serves more to
compare different materials at a stated set of conditions than to
6.1.5 Sensor, with rapid response and sensitivity capable of
predict their actual performance in the field under any condi-
detecting changes in the moisture content of the gas within the
tions.
dry chamber of 0.05 % relative humidity or less. This sensor
5.2 The water vapor transmission rate, under known and
may take any of a number of forms. For this purpose, the
carefully controlled conditions, may be used to evaluate the
following have been described in the literature: an electrical
vapor barrier qualities of a sheet. Direct correlation of values 4 5
resistance element, an electrolytic cell and a beam of infrared
obtained under different conditions of test temperature and
radiation.
relative humidity will be valid provided the barrier material
6.1.6 Data Collection, a means to convert the sensor’s
under test does not undergo changes in solid state (such as a
moisture-change response into a signal that can be used to
crystalline transition or melting point) at or between the
calculate the passage of moisture through the material under
conditions of test.
test.This may take the form of registering the time required for
6. Apparatus the signal to pass between two selected levels of relative
humidity, or the change in signal over a given interval of time.
6.1 The apparatus employed should have the following
elements: 6.1.7 Temperature Control, a means of maintaining the
6.1.1 Test Cell, designed to clamp a defined sample area
test-cell purge air and the test specimen at a constant known
sufficiently large to be representative of the sample (an area of
temperature within 60.1°C (60.18°F) is provided.
50 cm has been shown to be satisfactory) between two
6.1.8 Standard Films, which have been calibration by gravi-
chambers, one to contain an atmosphere of low relative
metric means. Various films have been found satisfactory with
humidity (sensor-side chamber), and the other an atmosphere
various thicknesses of PET most commonly used.
of higher relative humidity (humidified chamber) (see Fig. 1).
6.1.2 Clamping Arrangement, to allow rapid insertion and
7. Test Specimens or Sample
removal of the test specimen equipped with gaskets against
7.1 Test specimens shall be representative of the sample.
which the specimen is held to the dry chamber by a clamping
force sufficient to resist leakage.
6.1.3 Humidifi
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