ASTM E2240-02
(Test Method)Standard Test Method for Assessing the Current-Voltage Cycling Stability at 90C (194F) of Absorptive Electrochromic Coatings on Sealed Insulating Glass Units
Standard Test Method for Assessing the Current-Voltage Cycling Stability at 90C (194F) of Absorptive Electrochromic Coatings on Sealed Insulating Glass Units
SCOPE
1.1 The test described is a method for the accelerated aging and monitoring of the time-dependent performance of electrochromic windows (ECW). Cross sections of typical electrochromic windows have three to five-layers of coatings that include one to three active layers sandwiched between two transparent conducting electrodes (TCEs, see Section 3). Examples of the cross-sectional arrangements can be found in "Evaluation Criteria and Test Methods for Electrochromic Windows." (For acronyms used in this standard, see Appendix X1, section X1.1).
1.2 The test method is applicable only for layered (one or more active coatings between the TCEs) absorptive electrochromic coatings on sealed insulating glass (IG) units fabricated for vision glass (superstrate and substrate) areas for use in buildings, such as glass doors, windows, skylights, and exterior wall systems. The layers used for electrochromically changing the optical properties may be inorganic or organic materials between the superstrate and substrate.
1.3 The electrochromic coatings used in this test method will be subsequently exposed (see Test Methods E 2141) to solar radiation and deployed to control the amount of radiation by absorption and reflection and thus, limit the solar heat gain and amount of solar radiation that is transmitted into the building.
1.4 The test method is not applicable to other chromogenic devices, for example, photochromic and thermochromic devices.
1.5 The test method is not applicable to electrochromic windows that are constructed from superstrate or substrate materials other than glass.
1.6 The test method referenced herein is a laboratory test conducted under specified conditions. This test is intended to simulate and, possibly, to also accelerate actual in-service use of the electrochromic windows. Results from this test cannot be used to predict the performance with time of in-service units unless actual corresponding in-service tests have been conducted and appropriate analyses have been conducted to show how performance can be predicted from the accelerated aging tests.
1.7 The values stated in metric (SI) units are to be regarded as the standard.
1.8 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.
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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:E2240–02
Standard Test Method for
Assessing the Current-Voltage Cycling Stability at 90°C
(194°F) of Absorptive Electrochromic Coatings on Sealed
Insulating Glass Units
This standard is issued under the fixed designation E 2240; 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 of the electrochromic windows. Results from this test cannot
beusedtopredicttheperformancewithtimeofin-serviceunits
1.1 The test described is a method for the accelerated aging
unless actual corresponding in-service tests have been con-
and monitoring of the time-dependent performance of electro-
ducted and appropriate analyses have been conducted to show
chromic windows (ECW). Cross sections of typical electro-
how performance can be predicted from the accelerated aging
chromic windows have three to five-layers of coatings that
tests.
include one to three active layers sandwiched between two
1.7 The values stated in metric (SI) units are to be regarded
transparent conducting electrodes (TCEs, see Section 3). Ex-
as the standard.
amples of the cross-sectional arrangements can be found in
1.8 This standard does not purport to address all of the
“Evaluation Criteria and Test Methods for Electrochromic
2 safety concerns, if any, associated with its use. It is the
Windows.” (Foracronymsusedinthisstandard,seeAppendix
responsibility of the user of this standard to establish appro-
X1, section X1.1).
priate safety and health practices and determine the applica-
1.2 The test method is applicable only for layered (one or
bility of regulatory limitations prior to use.
more active coatings between the TCEs) absorptive electro-
chromic coatings on sealed insulating glass (IG) units fabri-
2. Referenced Documents
cated for vision glass (superstrate and substrate) areas for use
2.1 ASTM Standards:
in buildings, such as glass doors, windows, skylights, and
2.1.1 For additional useful standards related to this stan-
exterior wall systems. The layers used for electrochromically
dard, see Appendix X1, section X1.2.
changing the optical properties may be inorganic or organic
C 168 Terminology Relating to Building Materials
materials between the superstrate and substrate.
C 1048 Specification for Heat-Treated Flat Glass-Kind HS,
1.3 The electrochromic coatings used in this test method
Kind FT Coated and Uncoated Glass
will be subsequently exposed (see Test Methods E 2141)to
C 1199 Test Method for Measuring the Steady State Ther-
solar radiation and deployed to control the amount of radiation
malTransmittance of Fenestration Systems Using Hot Box
by absorption and reflection and thus, limit the solar heat gain
Methods
and amount of solar radiation that is transmitted into the
E 632 Practice toAid Prediction of Service Life of Building
building.
Components and Materials
1.4 The test method is not applicable to other chromogenic
E 903 Test Method for SolarAbsorptance, Reflectance, and
devices, for example, photochromic and thermochromic de-
Transmittance of Materials Using Integrating Spheres
vices.
E 1423 Practice for Determining the Steady State Thermal
1.5 The test method is not applicable to electrochromic
Transmittance of Fenestration Systems
windows that are constructed from superstrate or substrate
E 2094 Practice for Evaluating the Service Lifetime of
materials other than glass.
Chromogenic Glazings
1.6 The test method referenced herein is a laboratory test
E 2141 Test Methods for Assessing the Durability of Ab-
conducted under specified conditions. This test is intended to
sorptive Electrochromic Coatings on Sealed Insulating
simulate and, possibly, to also accelerate actual in-service use
Glass Units
This test method is under the jurisdiction of ASTM Committee E06 on
Performance of Buildings and is the direct responsibility of Subcommittee E06.22 Annual Book of ASTM Standards, Vol 04.06.
on Durability Performance of Building Constructions. Annual Book of ASTM Standards, Vol 15.02.
Current edition approved Oct. 10, 2002. Published December 2002. Annual Book of ASTM Standards, Vol 14.04.
2 6
Czanderna,A. W., and Lampert, C. M., “Evaluation Criteria and Test Methods Annual Book of ASTM Standards, Vol 12.02.
for Electrochromic Windows,” SERI/PR-255-3537, July 1990, Golden, CO; Solar Annual Book of ASTM Standards, Vol 04.11.
Energy Research Institute. Annual Book of ASTM Standards, Vol 04.12.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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.
E2240–02
E 2188 TestMethodforInsulatingGlassUnitPerformance 3.2.11 serviceability—the capability of a building product,
G113 Terminology Relating to Natural and Artificial component, assembly or construction to perform the func-
tion(s) for which it was designed and constructed.
Weathering Tests of Non-Metallic Materials
2.2 Canadian Standard: 3.2.12 service life—of a building component or material,
the period of time after installation during which all properties
CAN/CGSB 12.8 Insulating Glass Units
exceed minimum acceptable values when routinely main-
tained.
3. Terminology
3.3 For additional useful definitions for terminology used in
3.1 Definitions—Refer to terminology in Terminology
this standard, see Appendix X1, section X1.3.
C 168, Practice E 632, andTerminologyG113 for descriptions
of general terms.
4. Significance and Use
3.2 Definitions of Terms Specific to This Standard:
4.1 This test method is intended to provide a means for
3.2.1 accelerated aging test—anagingtestinwhichtherate
evaluatingthecurrent-voltagecyclingstabilityat90°C(194°F)
of degradation of building components or materials is inten- 2,9
of ECWs as described in 1.2. (See Appendix X1, sections
tionally accelerated from that expected in actual service.
X1.4-X1.7.)
3.2.2 bleached state—a descriptor for an ECW when no
ions reside in the electrochromic layer or after ions have been 5. Background
removed (or inserted, depending on the type of material) from
5.1 Observations and measurements have shown that some
the electrochromic layer(s) and if applicable, the maximum
of the performance parameters of ECWs have a tendency to
number of ions have been returned to the counterelectrode
deteriorate over time. In selecting the materials, device design,
layer to restore the photopic optical specular transmittance in
and glazing for any application, the ability of the glazing to
the bleached state (t ) from that of the photopic optical
b
perform over time is an indication of that glazing’s durability.
specular transmittance in the colored state (t ).
c
The ability of the product to perform over time, at or better
3.2.3 colored state—a descriptor for an ECW after ions
than specified requirements, is an indication of the service life
have been inserted (or removed, depending on the type of
of the glazings (see Practice E 2094). While these two indica-
material) into the electrochromic layer and, if applicable,
tors are related, the purpose of this standard test method is to
removed from the counterelectrode layer to reduce the photo-
assess the current-voltage cycling stability at 90°C (194°F) of
pic optical specular transmittance (of wavelengths from 400 to
ECWs.
730 nm) from that in the bleached state (t ).
b
5.2 ECWs perform a number of important functions in a
3.2.4 durability—the capability of maintaining the service-
building envelope including: minimizing the solar energy heat
ability of a product, component, assembly or construction over
gain; providing for passive solar energy gain; controlling a
a specified time.
variable visual connection with the outside world; enhancing
3.2.5 electrochromic coating—the multilayered materials
human comfort (heat gain), security, ventilation, illumination,
that include the electrochromic layers, other layers, and trans-
and glare control; providing for architectural expression, and
parent conducting oxide layers required for altering the optical
(possibly) improving acoustical performance. Some of these
properties of the coating.
functions may deteriorate in performance over time. Solar heat
3.2.6 electrochromic layer(s)—the material(s) in an ECW
gain through an ECW is decreased because of two principal
that alter its optical properties in response to the insertion or
processes. Energy from the visible part of the spectrum is
+ +
removal of ions, for example, Li or H .
absorbed by an ECW in the colored state. In addition, infrared
3.2.7 electrochromic window (ECW)—a window consisting
radiation is either absorbed by the ECW materials or is
of several layers of electrochromic and attendant materials,
reflected by the transparent conducting oxide layers that are
which are able to alter their optical properties in response to a
used for applying the coloring or bleaching potentials across
change in an applied electric field. The changeable optical
the other layers in the ECW.
properties include transmittance, reflectance, and absorptance.
5.3 It is possible, but difficult, to predict the time-dependent
3.2.8 ion conducting layer—the material in an ECW
performance of ECWs from accelerated aging tests because of
through which ions are transported between the electrochromic
the reasons listed below. Users of this document should be
layer and the ion storage layer and electron transport is
aware of these limitations when reviewing published perfor-
minimized.
mance results and their connection to durability.
3.2.9 ion storage layer or counter electrode layer—the
5.3.1 The degradation mechanisms of ECW materials or
material in an ECW that serves as a reservoir for ions that can
glazings, or both, are complex. In some cases, however, these
be inserted into the electrochromic layer.
mechanisms may be determined and quantified.
3.2.10 performance parameters—the photopic transmit-
5.3.2 The external factors that affect the performance of
tance ratio (PTR), of at least 5:1 (PTR = t /t ) between the
ECWsarenumerousandmaybedifficulttoquantify.However,
b c
bleached (for example, t of 60 to 70 %) and colored (for
b
example, t of 12 to 14 %) states; coloring and bleaching times
c
Czanderna, A. W., Benson, D. K., Jorgensen, G. J., Zhang, J-G., Tracy, C. E.,
of a few minutes; switching with applied voltages from ~1 to
and Deb, S. K., “Durability Issues and Service Lifetime Prediction of Electrochro-
3 V; and open-circuit memory of a few hours, for example,
mic Windows for Buildings Applications,” NREL/TP-510-22702, May 1997,
contemporaryECWstypicallyhaveopencircuitmemoriesof6
National Renewable Energy Laboratory, Golden, CO; Solar Energy Materials and
to 24 h. Solar Cells, 56, 1999, pp. 419-436.
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.
E2240–02
in some cases, the use, the environmental factors, and other accepted procedures or methods have been established for the
information that influence performance may be known. real-time testing of ECWs and because manufacturers and
5.3.3 Fenestration units with tested ECWs may be different users cannot wait 20 or more years for the real-time evaluation
from those planned for use in service. Some companies have a of each window design, accelerated life testing (ALT) methods
,
2 9
database of in-service performance that can be compared to and procedures must be used for evaluating ECW stability.
laboratory results. These include (a) rapid but realistic current-voltage (I-V)
5.4 Degradation factors (or stresses) for ECWs include the cyclic tests emphasizing the electrical properties, (b)ALT
ion insertion and removal processes; temperature; solar radia- parameters that are typically used in durability tests by
tion (especially UV); water vapor; atmospheric gases and standards organizations, (c) ALT parameters that are realistic
pollutants; thermal stresses such as shock from sudden rain, as for the intended use of large-area ECWs, and (d) how theALT
well as during the diurnal and annual temperature cycles; resultsmustberelatedtoreal-timetesting. Thepurposeofthis
electrochemically induced stresses in the multilayer thin-film test method is to assess the current-voltage cycling stability at
device; hail, dust, and wind; condensation and evaporation of 90°C (194°F) of ECWs at least 254 by 254 mm (10 by 10 in.).
,
2 9
water; and thermal expansion mismatches. These factors
NOTE 1—The seals in IGUs may fail at lower temperatures than those
may singularly or collectively limit the stability and durability
planned for testing, that is, 90°C (194°F). A seal failure will virtually
of ECWs. Because the ECWs are expected to have the
guarantee failure of the ECW coating, so no assessment of the stability of
multilayer of coatings on one of the surfaces in the cavity of the ECW coating will be made if a seal fails during the test.
NOTE 2—The test method may also be used for smaller ECWs to assess
double-pane or triple-pane IG units with an inert gas fill in the
the current-voltage cycling stability at 90°C (194°F) of prototype devices.
sealed space, many factors such as high humidity, atmospheric
The testing parameters chosen may only provide modest acceleration
gases and pollutants, condensation and evaporation of water,
factors. However, the quantitative parameters discussed in (a)–(c) above
and dust should not affect the durability of electrochromic
are presented and include a detailed description of the procedures for
coatings in IG units. 9
using an accelerated weathering unit.
5.4.1 Establishing test procedures from which ECW dura-
6. Apparatus (see Figs. 1 and 2 and Section 8.3 for
bility can be predicted and validated for in-service use is an
Descriptive Detail)
extremely crucial element for the commercialization of ECWs,
even for niche markets. To reduce the number of accelerated 6.1 Voltage Cycling Unit, for imposing voltage cycles to
test parameters that are required to predict the long-term alternately and repeatedly color and bleach the ECWs from a
performance of ECWs, accepted procedures or methods have fully bleached state to the colored state and back to the
not been established for testing ECWs. Because no uniformly bleached state.
FIG. 1 Top View Schematic Diagram of the Essential Components of an Oven and Computer-Controlled Electrical Cycling and Data
Acquisition System for Acce
...
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