ASTM E96/E96M-05
(Test Method)Standard Test Methods for Water Vapor Transmission of Materials
Standard Test Methods for Water Vapor Transmission of Materials
SIGNIFICANCE AND USE
The purpose of these tests is to obtain, by means of simple apparatus, reliable values of water vapor transfer through permeable and semipermeable materials, expressed in suitable units. These values are for use in design, manufacture, and marketing. A permeance value obtained under one set of test conditions may not indicate the value under a different set of conditions. For this reason, the test conditions should be selected that most closely approach the conditions of use. While any set of conditions may be used and those conditions reported, standard conditions that have been useful are shown in Appendix X1.
SCOPE
1.1 These test methods cover the determination of water vapor transmission (WVT) of materials through which the passage of water vapor may be of importance, such as paper, plastic films, other sheet materials, fiberboards, gypsum and plaster products, wood products, and plastics. The test methods are limited to specimens not over 11/ 4 in. (32 mm) in thickness except as provided in Section . Two basic methods, the Desiccant Method and the Water Method, are provided for the measurement of permeance, and two variations include service conditions with one side wetted and service conditions with low humidity on one side and high humidity on the other. Agreement should not be expected between results obtained by different methods. The method should be selected that more nearly approaches the conditions of use.
1.2 The values stated in inch-pound units are to be regarded separately as the standard. Within the text, the SI units are shown in parentheses. The values stated in each system are not exact equivalents; therefore each system must be used independently of the other. Combining values from two systems will result in non-conformance with the standard. However derived results can be converted from one system to other using appropriate conversion factors (see Table 1).
1.3 This standard does not purport to address all of the safety problems, 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.
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Standards Content (Sample)
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Designation:E96/E96M–05
Standard Test Methods for
1
Water Vapor Transmission of Materials
This standard is issued under the fixed designation E96/E96M; 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.
This standard has been approved for use by agencies of the Department of Defense.
A,B
TABLE 1 Metric Units and Conversion Factors
1. Scope
To Obtain (for the
1.1 These test methods cover the determination of water
Multiply by
same test condition)
vapor transmission (WVT) of materials through which the
WVT
passage of water vapor may be of importance, such as paper,
2 2
g/h·m 1.43 grains/h·ft
2 2
plastic films, other sheet materials, fiberboards, gypsum and
grains/h·ft 0.697 g/h·m
Permeance
plasterproducts,woodproducts,andplastics.Thetestmethods
2 7
g/Pa·s·m 1.75 3 10 1 Perm (inch-pound)
1
are limited to specimens not over 1 ⁄4 in. (32 mm) in thickness
−8 2
1 Perm (inch-pound) 5.72 3 10 g/Pa·s·m
except as provided in Section 9. Two basic methods, the
Permeability
8
g/Pa·s·m 6.88 3 10 1 Perm inch
Desiccant Method and the Water Method, are provided for the
−9
1 Perm inch 1.45 3 10 g/Pa·s·m
measurement of permeance, and two variations include service
A
These units are used in the construction trade. Other units may be used in
conditions with one side wetted and service conditions with
other standards.
B
low humidity on one side and high humidity on the other.
All conversions of mm Hg to Pa are made at a temperature of 0°C.
Agreementshouldnotbeexpectedbetweenresultsobtainedby
different methods. The method should be selected that more
D2301 Specification for Vinyl Chloride Plastic Pressure-
nearly approaches the conditions of use.
Sensitive Electrical Insulating Tape
1.2 The values stated in inch-pound units are to be regarded
E691 Practice for Conducting an Interlaboratory Study to
separately as the standard. Within the text, the SI units are
Determine the Precision of a Test Method
shown in parentheses.The values stated in each system are not
exact equivalents; therefore each system must be used inde-
3. Terminology
pendently of the other. Combining values from two systems
3.1 Definitions of terms used in this standard will be found
will result in non-conformance with the standard. However
in Terminology C168, from which the following is quoted:
derived results can be converted from one system to other
“water vapor permeability—the time rate of water vapor
using appropriate conversion factors (see Table 1).
transmission through unit area of flat material of unit thickness
1.3 This standard does not purport to address all of the
induced by unit vapor pressure difference between two specific
safety problems, if any, associated with its use. It is the
surfaces, under specified temperature and humidity conditions.
responsibility of the user of this standard to establish appro-
3.1.1 Discussion—Permeability is a property of a material,
priate safety and health practices and determine the applica-
but the permeability of a body that performs like a material
bility of regulatory limitations prior to use.
may be used. Permeability is the arithmetic product of per-
meance and thickness.
2. Referenced Documents
water vapor permeance—the time rate of water vapor
2
2.1 ASTM Standards:
transmission through unit area of flat material or construction
C168 Terminology Relating to Thermal Insulation
induced by unit vapor pressure difference between two specific
D449 Specification for Asphalt Used in Dampproofing and
surfaces, under specified temperature and humidity conditions.
Waterproofing
3.1.2 Discussion—Permeance is a performance evaluation
and not a property of a material.
1
These test methods are under the jurisdiction of ASTM Committee C16 on
3.2 water vapor transmission rate—the steady water vapor
Thermal Insulation and are the direct responsibility of Subcommittee C16.33 on
flowinunittimethroughunitareaofabody,normaltospecific
Thermal Insulation Finishes and Vapor Transmission.
parallel surfaces, under specific conditions of temperature and
Current edition approved May 1, 2005. Published June 2005. Originally
´1
approved in 1953. Last previous edition approved in 2000 as E96 – 00 . DOI: humidity at each surface.”
10.1520/E0096_E0096M-05.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4. Summary of Test Methods
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4.1 In the Desiccant Method the test specimen is sealed to
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. the open mouth of a test dish containing a desiccant, and the
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