ASTM D6490-99(2022)

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: D6490 − 99 (Reapproved 2022)
Standard Test Method for
Water Vapor Transmission of NonFilm Forming Treatments
Used on Cementitious Panels
This standard is issued under the fixed designation D6490; 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 D1734 Practice for Making Cementitious Panels for Testing
Coatings
1.1 This test method covers the determination of the rate at
D3924 Specification for Standard Environment for Condi-
whichwatervaporpassesthroughnonfilmformingtreatments,
tioning and Testing Paint, Varnish, Lacquer, and Related
such as silanes, siloxanes and blends of silanes/siloxanes
Materials
applied to cementitious substrates.
E104 Practice for Maintaining Constant Relative Humidity
1.2 This test method covers the use of the wet cup
by Means of Aqueous Solutions
technique, which most closely approaches the exterior condi-
tions for use for these materials. Other conditions can be used
3. Summary of Test Method
if agreed upon between purchaser and supplier. Agreement
3.1 The treated cementitious substrate is sealed to the open
should not be expected between results obtained by different
mouth of an assembly containing water with the treated side
methods or test conditions.
facing the water, and the assembly placed in a test chamber
1.3 The values stated in SI units of measurement are
with a controlled atmosphere maintained at 50 6 5 % relative
designated as the standard. Factors for conversion to inch-
humidity at 23 6 2 °C (73.5 6 3.5 °F). Periodic weighings of
pound units are given in 9.2.1.1 and 9.2.2.1.
the assembly are made to determine the rate of water vapor
1.4 This standard does not purport to address all of the movement through the specimen.
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-
priate safety, health, and environmental practices and deter-
4.1 One of the factors affecting the performance provided
mine the applicability of regulatory limitations prior to use.
by a cementitious treatment is how readily water vapor passes
1.5 This international standard was developed in accor-
through it. Hence, the water vapor transmission characteristics
dance with internationally recognized principles on standard-
of treatments are important in assessing their performance in
ization established in the Decision on Principles for the
practical use.
Development of International Standards, Guides and Recom-
4.2 The purpose of this test method is to obtain values of
mendations issued by the World Trade Organization Technical
water vapor transfer through treatments that range in perme-
Barriers to Trade (TBT) Committee.
ability from high to low. These values are for use in design,
manufacture, and marketing.
2. Referenced Documents
4.3 Water vapor transmission is not a linear function of film
2.1 ASTM Standards:
thickness, temperature or relative humidity.
D823 Practices for Producing Films of Uniform Thickness
of Paint, Coatings and Related Products on Test Panels 4.4 Values of water vapor transmission rate (WVT) and
D1193 Specification for Reagent Water water vapor permeance (WVP) can be used in the relative
rating of treatments only if the treatments are tested under the
same closely controlled conditions of temperature and relative
humidity.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.47 on Concrete, Stone and Masonry Treatments.
5. Apparatus
CurrenteditionapprovedJune1,2022.PublishedJuly2022.Originallyapproved
5.1 Assembly, consisting of a container, typically with an
in 1999. Last previous edition approved in 2014 as D6490 – 99 (2014). DOI:
10.1520/D6490-99R22.
opening of approximately 75 mm (3 in.) by 150 mm (6 in.).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
The depth of the dish is such that there is a 20 6 5 mm (0.8 6
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
0.2 in.) distance between the water surface and the surface of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. the under surface of the test specimen, with a water depth of at
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6490 − 99 (2022)
least 5 mm (0.2 in.). The assembly should be made of a 8.1.1 Fill the assembly with water to within 20 6 5 mm (0.8
noncorroding material, impermeable to water or water vapor in 6 0.2 in.) of the treated substrate.
order to be found acceptable. The treated cementitious sub- 8.1.2 Seal the treated substrate to the top edge of the
strate can be sealed with wax or sealant to the assembly. If the assembly with wax or sealant with the treated face placed
assembly is made of aluminum, it must be anodized or given a facing the water.
protective clear coating to prevent corrosion.
8.2 Weigh the test assemblies to 0.1 g. and place them in the
5.2 TestChamber,withacontrolledtemperatureandrelative test chamber. Record time, temperature, and relative humidity.
humidity as specified in Section 3. Air shall be circulated Unless other conditions are agreed upon between the purchaser
throughout the chamber to maintain uniform conditions at all andtheseller,performthetest(s)inachambermaintainedat23
test locations. 6 2 °C (73 6 3.5 °F) and 50 6 5 % relative humidity.
8.2.1 In general, the test assemblies should be weighed
NOTE 1—For maintaining constant relative humidities other than those
every 24 h for a period of time until the weight change per 24 h
specified in 3.1, by means of aqueous solutions, refer to procedures
has become consistent. The time that weighings are taken
outlined in Practice E104.
should be recorded to the precision of approximately 1 % of
5.3 Analytical Balance, having an adequate capacity for the
the time span between weighings. Thus, if weighings are made
weight of the test assemblies and a sensitivity of 10 mg
every day, a time to the nearest 15 min would be allowe
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