ASTM E2649-20

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Designation: E2649 − 12 E2649 − 20
Standard Test Method for
Determining Argon Concentration in Sealed Insulating Glass
Units Using Spark Emission Spectroscopy
This standard is issued under the fixed designation E2649; 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
1.1 This test method covers procedures for using a spark emission spectroscope to determine the concentration of argon gas in
the space between the lites of a sealed insulating glass unit.
1.2 This is a non-destructive test method.
1.3 This test method shall be used only in a controlled laboratory environment.
1.4 This test method is applicable for insulating glass units where argon has been added to the sealed insulating glass cavity
and the balance of the gas is atmospheric air.
1.5 This test method is applicable for clear, double-glazed insulating glass units.
1.6 This test method is applicable for double-glazed insulating glass units with one lite having a metallic coating or tinted glass,
or both, and with clear glass as the other lite.
1.7 This test method is applicable for triple-glazed insulating glass units only when the center lite of glass has a metallic coating
(either low emissivity (low E) or reflective) and both of the other lites are clear glass.
1.8 This test method also includes a procedure for verifying the accuracy of the readings of the test apparatus.
1.9 The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathematical
conversions to inch-pound units that after SI units are provided for information only and are not considered standard.
1.10 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific warning statements, refer to Section 7.17. on Hazards.
1.11 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:
C162 Terminology of Glass and Glass Products
C717 Terminology of Building Seals and Sealants
E631 Terminology of Building Constructions
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E631 Terminology of Building Constructions
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2190 Specification for Insulating Glass Unit Performance and Evaluation
3. Terminology
3.1 Definitions: For definitions of terms found in this test method, refer to Terminologies C162, C717, and E631.
3.2 Definitions of Terms Specific to This Standard:
This test method is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.22 on Durability
Performance of Building Constructions.
Current edition approved April 1, 2012Feb. 15, 2020. Published May 2012February 2020. Originally approved in 2009. Last previous edition approved in 20092012 as
E2649 – 09. DOI: 10.1520/E2649-09.–12. DOI: 10.1520/E2649–20.
For referenced ASTM standards, visit the ASTM website, www.astm.org,or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
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E2649 − 20
3.2.1 sealed insulating glass unit—an assembled unit, comprising sealed lites of glass separated by dehydrated space(s),
normally intended for clear vision areas of buildings.
4. Summary of Test Method
4.1 The spark emission spectroscope is placed against the glass surface of a sealed insulating glass unit in a prescribed manner.
A high voltage, at low current, is applied to the glass surface. This voltage creates a spark which induces a plasma from the gas
molecules inside the test specimen. This causes light emissions (photons) of characteristic wavelengths. The instrument then
collects the photons and analyzes them by spark emission spectroscopy. The resulting spectrum is compared to calibration data
internal to the instrument to determine the concentration of argon inside the unit.
FIG. 1 Example of Test Stand
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FIG. 2 Another Example of Test Stand
5. Significance and Use
5.1 This test method is intended to provide a means for determining the concentration of argon in sealed insulating glass units
under controlled conditions in compliance with the apparatus manufacturer’s instructions.
5.2 This is a non-destructive test method in that the edge seal of the test specimen is not breached in order to determine the argon
gas concentration. However, damage to some glass coatings on the inner surfaces of the glass can occur.
5.3 This test method has been developed based on data collected in a controlled laboratory environment.
5.4 The device shall be used to determine the argon gas concentration in insulating glass units in a controlled laboratory
environment. Refer to 12.3.
5.5 This test method may be used to determine the argon gas concentration before, during, or after the insulating glass unit is
subjected to durability tests.
5.6 The accuracy of the test method is dependent upon the accuracy of the Spark Emission Spectroscope. When the
concentration of the argon being measured is below certain levels, this test method is not applicable. See the spectroscope
manufacturer’s literature for recommended levels of accuracy of a given model.
6. Apparatus
6.1 Spark Emission Spectroscope:
6.1.1 The apparatus employs a high voltage, at low current, source and employs spark emission spectroscopy.
6.1.2 The head of the spark emission spectroscope contains an electrode which is used to apply the voltage to the glass surface
of the test specimen. It also contains a light collector which transmits light emissions to a spectrometer for processing.
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6.1.3 Different models of the spark emission spectroscope shall be acceptable provided that new models demonstrate accuracy
limits as defined in Section 10.
6.2 Specimen Stand:
6.2.1 The test specimen shall be supported in a vertical position or up to 30° off vertical position.
6.2.2 If necessary, a stand is used to support the test specimens. For example test stands, see Fig. 1 and Fig. 2.
6.3 Background:
6.3.1 A non-reflective black background shall be positioned behind the test specimen. Examples of background materials
include photographic black fabric and black closed-cell foam.
7. Hazards
7.1 Warning—The high voltage of the spark emission spectroscope used in this test method can be harmful. Appropriate
protective measures shall be observed. Refer to the instrument manufacturer’smanufacturer’s instruction manual.
7.2 Warning—This instrument uses high voltage; persons with heart conditions or who use pacemakers should not use this
instrument.
7.3 Warning—This instrument should NEVER be used to measure any flammable substances, nor be used in any flammable
environment. Make certain the insulating glass unit does not contain any flammable substances.
8. Test Specimens
8.1 Any sealed insulating glass unit cavity that allows the spark emission spectroscope to excite the gas present in the
airspacecavity can be tested using this test method.
8.2 Typically, test specimens are 355 mm ×by 505 mm (14 in. ×by 20 in.) sealed insulating glass units constructed using one
5 1 5
lite of 4 mm ( ⁄32 in.) clear uncoated glass, a 12 mm ( ⁄2 in.) air space, and one lite of 4 mm ( ⁄32 in.) coated low E glass. Variations
in the specimen construction may require a correction. See the instrument manufacturer’s instruction manual for further
information.Best results are obtained if one of the lites of glass shall have a metallic, low emissivity coating on its cavity facing
surface.
9. Calibration
9.1 Adjustment of the instrument is recommended to be performed only by the manufacturer of the instrument or an authorized
service representative. The user shall verify the accuracy of the instrument readings using Section 10.
10. Verification
10.1 Verification of the accuracy of the instrument readings shall be performed by the user.
10.2 Verification Specimens:
10.2.1 The verification specimens shall be comprised of two lites of 4 mm glass, and a 12.0 mm 6 0.8 mm cavity. One of the
lites of glass shall have a metallic, low emissivity coating on its cavity facing surface. Specimen size is suggested to be 350 mm
×by 350 mm.
10.2.2 Follow the instrument manufacturer’smanufacturer’s instruction manual for gas filling of verification specimens. Fill the
verification specimens with reference gas mixtures according to 10.3.
NOTE 1—Different models of the spark emission spectroscope may have different requirements for gas filling of verification specimens. Consult the
manufacturer’s instruction manual specific to the model of use.
10.3 Reference Gas Mixtures:
10.3.1 At least two reference gas mixtures that contain known percentages of argon and atmospheric air are required for
verification. For increased confidence in the measurements over the capability range of the instrument, additional reference gas
mixtures are recommended.
10.3.2 The first reference gas mixture shall have an argon concentration of approximately 90 %.
10.3.3 The second reference gas mixture shall have an argon concentration of approximately 80 %.
10.3.4 If the user has defined a specific argon gas concentration, then a third reference gas mixture is recommended at the
defined argon concentration.
NOTE 2—Suitable gas mixtures can be obtained with a certificate of analysis of the mixture from commercial gas suppliers. The accuracy of the results
of this test method depends on the accuracy of the certified reference gas mixtures.
This method wasis based on use of the Gasglass 1002V.2 device (the wand model). As of this writing, there are other models of the device which include V1 and V2
(handheld models). handheld model). The sole source of supply of these apparatusesthis apparatus known to the committee at this time is Sparklike, Ltd., Särkiniementie 5
C6, 00210 Helsinki, Finland, http://www.sparklike.com. If you are a
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