ASTM D1653-13(2021)

Standard Test Methods for Water Vapor Transmission of Organic Coating Films

SIGNIFICANCE AND USE
5.1 One of the factors affecting the performance provided by an organic coating is its capability of resisting or aiding the passage of water vapor. In some services, for example, exterior wood and masonry, the coating has to allow moderate amounts of water vapor to pass through the film without damage to it. Hence, the water vapor transmission characteristics of coatings are important in assessing their performance in practical use.  
5.2 The purpose of these test methods is to obtain values of water vapor transfer through coatings that range in permeability from high to low. These values are for use in design, manufacture, and marketing.  
5.3 The water vapor transmission is not a linear function of film thickness, temperature or relative humidity.  
5.4 Values of water vapor transmission rate (WVT) and water vapor permeance (WVP) can be used in the relative rating of coatings only if the coatings are tested under the same closely controlled conditions of temperature and relative humidity, and if their thicknesses are equal.  
5.5 Test Method A—The Dry Cup Method is the preferred test method for obtaining values that relate to conventional dwellings where high relative humidities are not anticipated.  
5.6 Test Method B—The Wet Cup Method is the preferred test method for obtaining values that relate to applications where high relative humidities are anticipated in the vicinity of the barrier material. In general, the more permeable a coating is to the passage of moisture as is typical of many water-reducible coatings, the greater its affinity for water and the greater the increase in transmission when tested in and exposed to high humidities. Absorption of water may make a coating less dense, thus allowing moisture to diffuse easily and cause a much higher moisture vapor transmission rate, (WVTR) than would occur in drier environments.
SCOPE
1.1 These test methods cover the determination of the rate at which water vapor passes through films of paint, varnish, lacquer, and other organic coatings. The films may be free films or they may be applied to porous substrates.  
1.2 A similar, but more generally applicable test method is Test Methods E96 which should be considered when other materials are involved.  
1.3 Two test methods are covered in Test Methods D1653 as follows:  
1.3.1 Test Method A—Dry Cup Method, and  
1.3.2 Test Method B—Wet (Payne) Cup Method.  
1.3.3 Agreement should not be expected between results obtained by different methods or test conditions. The method that most closely approaches the conditions of use should be selected.  
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. Factors for conversion are stated in 13.2.1.2 and 13.2.2.2.  
1.5 There are instruments on the market that purport to measure water vapor transmission of films more easily and rapidly than the methods described in Test Methods D1653 and E96. They run essentially the same kinds of tests as in the ASTM methods, but do so instrumentally. However, it appears that no side-by-side tests have been run comparing results from measurements with such instruments to these ASTM methods for precision and accuracy.  
1.6 This standard does not purport to address 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-2021
• ICS: 25.220.60 - Organic coatings
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.23 - Physical Properties of Applied Paint Films

Relations

• Refers: ASTM D4708-24 - Standard Practice for Preparation of Uniform Free Films of Organic Coatings
• Effective Date: 15-Jan-2024
• Refers: ASTM D1005-95(2020) - Standard Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
• Effective Date: 01-Jun-2020
• Refers: ASTM D4708-19 - Standard Practice for Preparation of Uniform Free Films of Organic Coatings
• Effective Date: 01-Mar-2019
• Refers: ASTM D823-17 - Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
• Effective Date: 01-Dec-2017
• Refers: ASTM D823-95(2012) - Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
• Effective Date: 01-Nov-2012
• Refers: ASTM D4708-12 - Standard Practice for Preparation of Uniform Free Films of Organic Coatings
• Effective Date: 01-Jul-2012
• Refers: ASTM E104-02(2012) - Standard Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions
• Effective Date: 01-Apr-2012
• Refers: ASTM D4708-07 - Standard Practice for Preparation of Uniform Free Films of Organic Coatings
• Effective Date: 01-Nov-2007
• Refers: ASTM D1005-95(2007) - Standard Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
• Effective Date: 01-Nov-2007
• Refers: ASTM E104-02(2007) - Standard Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions
• Effective Date: 01-Oct-2007
• Refers: ASTM D823-95(2007) - Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
• Effective Date: 01-Jun-2007
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM D4708-99(2004) - Standard Practice for Preparation of Uniform Free Films of Organic Coatings
• Effective Date: 01-Jun-2004
• Refers: ASTM E104-02 - Standard Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions
• Effective Date: 10-Oct-2002
• Refers: ASTM D823-95(2001) - Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
• Effective Date: 01-Jan-2001

Overview

ASTM D1653-13(2021): Standard Test Methods for Water Vapor Transmission of Organic Coating Films provides well-established procedures for determining the rate at which water vapor passes through films of paint, varnish, lacquer, and other organic coatings. These methods are instrumental in evaluating the water vapor transmission characteristics - also known as water vapor permeance - of coatings applied as free films or to porous substrates. This standard is widely used across industries to assess and compare the protective capabilities and durability of coatings under varying humidity conditions.

Water vapor transmission is a key property impacting the performance of organic coatings, especially for applications like exterior wood and masonry where managing moisture flow through the coating layer is essential to avoid degradation. By following the standardized procedures outlined in ASTM D1653, manufacturers, designers, and regulators can consistently evaluate and compare products for use in environments with differing moisture profiles.

Key Topics

• Water Vapor Transmission Rate (WVT): Measures the steady rate of water vapor flow through a coating film, crucial for determining coating performance under specific environmental conditions.
• Water Vapor Permeance (WVP): Describes the ability of the coating to transmit moisture when subjected to a unit vapor pressure difference.
• Test Method A – Dry Cup Method: Preferred for typical indoor or moderate humidity applications. Uses desiccant in the test cup to create a low-humidity environment.
• Test Method B – Wet Cup Method: Suited for high-humidity environments. Uses water in the test cup to maintain a moist source beneath the film.
• Controlled Conditions: Accurate comparisons require identical film thicknesses, temperatures, and relative humidities. Water vapor transmission is not a linear function of thickness, temperature, or humidity.

Applications

ASTM D1653 test methods are essential for product development, quality assurance, and material selection in various industries, including:

• Architectural and Protective Coatings: Evaluating paint and coating formulations for buildings, bridges, and infrastructure where moisture management is critical.
• Flooring and Wall Systems: Assessing performance of coatings applied to masonry, wood, or composite materials in environments exposed to variable humidity.
• Research and Development: Comparing new or modified coating systems under standardized and controlled laboratory conditions.
• Building Design and Maintenance: Informing selection of coatings based on required moisture permeability to balance protection against water ingress with allowing necessary vapor diffusion.
• Marketing Claims and Product Declarations: Supporting transparent and comparable product data for end users and regulators.

Related Standards

• ASTM E96: Test Methods for Water Vapor Transmission of Materials - a broader method encompassing various types of materials, not only organic coatings.
• ASTM D823: Practices for Producing Films of Uniform Thickness of Paint, Coatings, and Related Products on Test Panels.
• ASTM D1005: Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers.
• ASTM D1193: Specification for Reagent Water - referenced for preparation of test materials.
• ASTM D4708: Practice for Preparation of Uniform Free Films of Organic Coatings.
• ASTM E104: Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions.

Practical Value

Using ASTM D1653 ensures reliable, reproducible data for the water vapor transmission of organic coating films, enabling manufacturers and designers to optimize coating selection and formulation for specific environmental exposures. This standard provides a scientific basis for comparing products and supports the design of building envelopes and protective systems that balance weather protection with the need for moisture control. Proper application of these methods aids in extending the life and performance of coated substrates in diverse conditions.

Keywords: water vapor transmission, water vapor permeance, organic coatings, ASTM D1653, protective coatings, water vapor barrier, paint permeability, moisture management, test methods, coating durability.

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: D1653 − 13 (Reapproved 2021)
Standard Test Methods for
Water Vapor Transmission of Organic Coating Films
This standard is issued under the fixed designation D1653; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 Thesetestmethodscoverthedeterminationoftherateat
ization established in the Decision on Principles for the
which water vapor passes through films of paint, varnish,
Development of International Standards, Guides and Recom-
lacquer,andotherorganiccoatings.Thefilmsmaybefreefilms
mendations issued by the World Trade Organization Technical
or they may be applied to porous substrates.
Barriers to Trade (TBT) Committee.
1.2 A similar, but more generally applicable test method is
Test Methods E96 which should be considered when other
2. Referenced Documents
materials are involved.
2.1 ASTM Standards:
1.3 TwotestmethodsarecoveredinTestMethodsD1653as
D823Practices for Producing Films of Uniform Thickness
follows:
of Paint, Coatings and Related Products on Test Panels
1.3.1 Test Method A—Dry Cup Method, and
D1005Test Method for Measurement of Dry-Film Thick-
1.3.2 Test Method B—Wet (Payne) Cup Method.
ness of Organic Coatings Using Micrometers
1.3.3 Agreement should not be expected between results
D1193Specification for Reagent Water
obtained by different methods or test conditions. The method
D4708Practice for Preparation of Uniform Free Films of
that most closely approaches the conditions of use should be
Organic Coatings
selected.
E96Test Methods for Water Vapor Transmission of Materi-
als
1.4 Thevaluesstatedininch-poundunitsaretoberegarded
E104Practice for Maintaining Constant Relative Humidity
as standard. The values given in parentheses are mathematical
by Means of Aqueous Solutions
conversions to SI units that are provided for information only
and are not considered standard. Factors for conversion are
3. Terminology
stated in 13.2.1.2 and 13.2.2.2.
3.1 Definitions of Terms Specific to This Standard:
1.5 There are instruments on the market that purport to
3.1.1 water vapor transmission rate, WVT, n—the steady
measure water vapor transmission of films more easily and
water vapor flow in unit time through unit area of a body,
rapidlythanthemethodsdescribedinTestMethodsD1653and
between two specific parallel surfaces, under specific condi-
E96. They run essentially the same kinds of tests as in the
tions of temperature and humidity at each surface. Accepted
ASTM methods, but do so instrumentally. However, it appears
inch-poundunitisgrainspersquarefootperhour.AcceptedSI
thatnoside-by-sidetestshavebeenruncomparingresultsfrom
unit is grams per square metre per 24 h.
measurements with such instruments to these ASTM methods
for precision and accuracy. 3.1.2 water vapor permeance, WVP, n—the steady water
vapor flow in unit time through unit area of a body (WVT)
1.6 This standard does not purport to address the safety
inducedbyunitvaporpressuredifference(∆p)betweenthetwo
concerns, if any, associated with its use. It is the responsibility
surfaces of a coating. Therefore, WVP=WVT⁄∆p. Accepted
of the user of this standard to establish appropriate safety,
inch-pound unit is grains per square foot per hour per inch of
health, and environmental practices and determine the appli-
mercury (called a perm).Accepted SI unit is grams per square
cability of regulatory limitations prior to use.
metre per 24 h per millimetre of mercury (called a metric
perm).
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.23 on Physical Properties of Applied Paint
Films. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 1, 2021. Published June 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1959. Last previous edition approved in 2013 as D1653–13. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D1653-13R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1653 − 13 (2021)
3.1.3 vapor source, n—humidity in the dry cup method and greatertheincreaseintransmissionwhentestedinandexposed
water in the wet cup method. to high humidities. Absorption of water may make a coating
lessdense,thusallowingmoisturetodiffuseeasilyandcausea
3.1.4 vapor sink, n—desiccant used in the dry cup method
much higher moisture vapor transmission rate, (WVTR) than
and50%ornear0%relativehumidityinthewetcupmethod.
would occur in drier environments.
4. Summary of Test Methods
6. Apparatus
4.1 In Test MethodA(Dry Cup Method), the test specimen
6.1 Perm Cup or Dish, consisting of a container made of a
is sealed to the open mouth of a cup or dish containing
noncorrodingmaterial,impermeabletowaterorwatervapor.If
desiccant, and the assembly placed in a test chamber with a
the cup or dish is made of aluminum, it must be anodized or
controlled atmosphere. Two sets of exposure conditions are
given a protective clear coating to prevent corrosion.
acceptable for this test method.
6.1.1 Onetypeofcupthatissuitablehasaflangededgeand
4.1.1 Condition A, consisting of 50% relative humidity at
is equipped with a separate corresponding flange, so that the
73°F (23°C), and
test specimen can be held between them. The contacting faces
4.1.2 Condition B, consisting of 90% relative humidity at
of the flanges shall be ground to such flatness that when the
100°F (38°C).
filmisinposition,moisturetransfercanoccuronlythroughthe
4.2 In Test Method B (Wet Cup Method), the test specimen
exposed film area. For hard films, or films having a very rough
is sealed to the open mouth of a cup or dish containing water,
surface, a soft rubber gasket may be inserted between the film
and the assembly placed in a test chamber with a controlled
and the flange. The flanges shall then be held together with
atmosphere.Twosetsofexposureconditionsareacceptablefor
suitable clamps.
this test method:
6.1.2 Another suitable cup is any open circular or rectangu-
4.2.1 Condition A, consisting of 50% relative humidity at
lardishtowhichthetestfilmcanbesealedwithwaxorsealant.
73°F (23°C), and
6.2 Test Chamber,withacontrolledtemperatureandrelative
4.2.2 Condition C, consisting of very low (near zero)
humidity as specified in Section 4. Air shall be circulated
relative humidity at 73°F (23°C).
throughout the chamber to maintain uniform conditions at all
4.3 In both methods, periodic weighings of the cup or dish
test locations. For low or high humidity conditions, a standard
are made to determine the rate of water vapor movement
desiccatororothersuitablecabinetmaybeused.Formaintain-
through the specimen.
ing constant relative humidity by means of aqueous solutions,
refer to procedures outlined in Practice E104.
5. Significance and Use
6.3 Analytical Balance, having an adequate capacity for the
5.1 One of the factors affecting the performance provided
weight of the test cups and a sensitivity of 1 mg.
by an organic coating is its capability of resisting or aiding the
passageofwatervapor.Insomeservices,forexample,exterior
7. Reagents and Materials
woodandmasonry,thecoatinghastoallowmoderateamounts
7.1 Purity of Water—Unless otherwise indicated, reference
of water vapor to pass through the film without damage to it.
towatershallbeunderstoodtomeanreagentwaterconforming
Hence,thewatervaportransmissioncharacteristicsofcoatings
to Type IV of Specification D1193.
are important in assessing their performance in practical use.
7.2 Desiccant, consisting of either anhydrous calcium chlo-
5.2 The purpose of these test methods is to obtain values of
ride (CaCL ) or anhydrous magnesium perchlorate (Mg-
water vapor transfer through coatings that range in permeabil-
(CLO ) ). The calcium chloride should be dried at 400°F
4 2
ity from high to low. These values are for use in design,
(200°C) before use. If calcium chloride will react with the test
manufacture, and marketing.
specimen, an adsorbing desiccant such as a silica gel may be
5.3 The water vapor transmission is not a linear function of
used but the moisture gain by this desiccant during the test
film thickness, temperature or relative humidity.
must be limited to 4%. Use caution in handling magnesium
5.4 Values of water vapor transmission rate (WVT) and perchlorate because of possible chemical reaction that may be
water vapor permeance (WVP) can be used in the relative produced if it comes in contact with some organic materials
ratingofcoatingsonlyifthecoatingsaretestedunderthesame and is subsequently heated to regenerate the anhydrous salt.
closely controlled conditions of temperature and relative
7.3 Sealant, such as wax for attaching the test specimen to
humidity, and if their thicknesses are equal.
the top of the perm cup or dish. It must be highly resistant to
5.5 Test Method A—The Dry Cup Method is the preferred the passage of water vapor. It must not lose weight to, or gain
test method for obtaining values that relate to conventional weight from, the atmosphere in an amount, over the required
dwellings where high relative humidities are not anticipated. period of time, that would affect the test results by more than
2%.Itmustnotaffectthevaporpressureinawater-filleddish.
5.6 Test Method B—The Wet Cup Method is the preferred
test method for obtaining values that relate to applications
NOTE 1—Among acceptable sealants are (1) a 60:40 mixture of
microcrystalline wax and refined crystalline parafin wax, (2) tissue
wherehighrelativehumiditiesareanticipatedinthevicinityof
embedding wax, and (3) a 50:50 mixture of beeswax and rosin.
the barrier material. In general, the more permeable a coating
is to the passage of moisture as is typical of many water- 7.4 Release Substrate,preparefreefilms,wheneverpossible
reducible coatings, the greater its affinity for water and the to eliminate the potential interference of substrates, on release
D1653 − 13 (2021)
paper glass coated with halosilane compound, polyhexafluo- TEST METHOD A—DRY CUP METHOD
ropropylene sheet, or metal panels wrapped with Tedlar
9. Test Conditions
polyvinylfluoride film (useful for coatings that must be baked)
9.1 Unless other conditions are agreed upon between the
following procedures outlined in Practice D4708.
purchaserandtheseller,thetestsshallbeperformedunderone
7.5 Film Support, for preparing films that are too brittle or
or more of the following conditions:
otherwise unsatisfactory for handling as free films. Support
9.1.1 Condition A—Test chamber or cabinet maintained at
materials such as paper charts, filter paper, and glass cloth
73° 6 1°F (23 6 0.6°C) and 50 6 2% relative humidity.
have been found satisfactory in some instances. Such support
9.1.2 Condition B—Test chamber or desiccator maintained
can have an effect on the test results.
at 100 6 1°F (38 6 0.6°C) and 90 6 2% relative humidity.
10. Procedure
8. Test Specimens
10.1 Prepare at least three perm cups or dishes for each test
8.1 It is ver
...