ASTM E1171-15(2019)

Standard Test Methods for Photovoltaic Modules in Cyclic Temperature and Humidity Environments

SIGNIFICANCE AND USE
4.1 The useful life of photovoltaic modules may depend on their ability to withstand repeated temperature cycling with varying amounts of moisture in the air. These test methods provide procedures for simulating the effects of cyclic temperature and humidity environments. An extended duration damp heat procedure is provided to simulate the effects of long term exposure to high humidity.  
4.2 The durations of the individual environmental tests are specified by use of this test method; however, commonly used durations are 50 and 200 thermal cycles, 10 humidity-freeze cycles, and 1000 h of damp heat exposure, as specified by module qualification standards such as IEC 61215 and IEC 61646. Longer durations can also be specified for extended duration module stress testing.  
4.3 Mounting—Test modules are mounted so that they are electrically isolated from each other, and in such a manner to allow free air circulation around the front and back surfaces of the modules.  
4.4 Current Biasing:  
4.4.1 During the thermal cycling procedure, test modules are operated without illumination and with a forward-bias current equal to the maximum power point current at standard reporting conditions (SRC, see Test Methods E1036) flowing through the module circuitry.  
4.4.2 The current biasing is intended to stress the module interconnections and solder bonds in ways similar to those that are believed to be responsible for fill-factor degradation in field-deployed modules.  
4.5 Effects of Test Procedures—Data generated using these test methods may be used to evaluate and compare the effects of simulated environment on test specimens. These test methods require determination of both visible effects and electrical performance effects.  
4.5.1 Effects on modules may vary from none to significant changes. Some physical changes in the module may be visible when there are no apparent electrical changes in the module. Similarly, electrical changes may occur with no visible changes in...
SCOPE
1.1 These test methods provide procedures for stressing photovoltaic modules in simulated temperature and humidity environments. Environmental testing is used to simulate aging of module materials on an accelerated basis.  
1.2 Three individual environmental test procedures are defined by these test methods: a thermal cycling procedure, a humidity-freeze cycling procedure, and an extended duration damp heat procedure. Electrical biasing is utilized during the thermal cycling procedure to simulate stresses that are known to occur in field-deployed modules.  
1.3 These test methods define mounting methods for modules undergoing environmental testing, and specify parameters that must be recorded and reported.  
1.4 These test methods do not establish pass or fail levels. The determination of acceptable or unacceptable results is beyond the scope of these test methods.  
1.5 Any of the individual environmental tests may be performed singly, or may be combined into a test sequence with other environmental or non-environmental tests, or both. Certain pre-conditioning tests such as annealing or light soaking may also be necessary or desirable as part of such a sequence. The determination of any such sequencing and pre-conditioning is beyond the scope of this test method.  
1.6 These test procedures are limited in duration and therefore the results of these tests cannot be used to determine photovoltaic module lifetimes.  
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.9 This international standard was developed in accordance with internati...

General Information

• Status: Published
• Publication Date: 31-Mar-2019
• ICS: 27.160 - Solar energy engineering
• Technical Committee: E44 - Solar, Geothermal and Other Alternative Energy Sources
• Drafting Committee: E44.09 - Photovoltaic Electric Power Conversion

Relations

• Replaces: ASTM E1171-15 - Standard Test Methods for Photovoltaic Modules in Cyclic Temperature and Humidity Environments
• Effective Date: 01-Apr-2019
• Refers: ASTM E1036-15(2019) - Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
• Effective Date: 01-Apr-2019
• Refers: ASTM E1462-12(2018) - Standard Test Methods for Insulation Integrity and Ground Path Continuity of Photovoltaic Modules
• Effective Date: 01-Feb-2018
• Refers: ASTM E1036-15 - Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
• Effective Date: 01-Feb-2015
• Refers: ASTM E772-13 - Standard Terminology of Solar Energy Conversion
• Effective Date: 01-Sep-2013
• Refers: ASTM E1036-12 - Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
• Effective Date: 01-Dec-2012
• Refers: ASTM E1799-12 - Standard Practice for Visual Inspections of Photovoltaic Modules
• Effective Date: 01-Dec-2012
• Refers: ASTM E1462-12 - Standard Test Methods for Insulation Integrity and Ground Path Continuity of Photovoltaic Modules
• Effective Date: 01-Mar-2012
• Refers: ASTM E772-11 - Standard Terminology of Solar Energy Conversion
• Effective Date: 01-Sep-2011
• Refers: ASTM E1036-08 - Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
• Effective Date: 01-Nov-2008
• Refers: ASTM E1799-08 - Standard Practice for Visual Inspections of Photovoltaic Modules
• Effective Date: 01-Apr-2008
• Refers: ASTM E1036-02(2007) - Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
• Effective Date: 01-Nov-2007
• Refers: ASTM E1462-00(2006) - Standard Test Methods for Insulation Integrity and Ground Path Continuity of Photovoltaic Modules
• Effective Date: 01-Mar-2006
• Refers: ASTM E772-05 - Standard Terminology Relating to Solar Energy Conversion
• Effective Date: 01-Apr-2005
• Refers: ASTM E1036-02 - Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
• Effective Date: 10-Oct-2002

Overview

ASTM E1171-15(2019): Standard Test Methods for Photovoltaic Modules in Cyclic Temperature and Humidity Environments provides comprehensive procedures to evaluate how photovoltaic (PV) modules withstand the stresses caused by fluctuating temperatures and varying humidity conditions. Developed by ASTM, this standard aims to simulate the aging and environmental exposure of PV modules in a controlled, accelerated manner, offering vital information for manufacturers, testers, and certification bodies within the solar energy industry.

Environmental testing according to ASTM E1171-15(2019) helps ensure solar modules maintain their performance and structural integrity under real-world climate variations, supporting reliability assessments and qualification processes.

Key Topics

• Environmental Test Methods: Includes three major procedures-

  • Thermal Cycling: Repeatedly exposes modules to extreme low and high temperatures.
  • Humidity-Freeze Cycling: Alternates between high humidity and sub-freezing conditions.
  • Damp Heat Exposure: Simulates long-term exposure to high humidity at elevated temperatures.

• Electrical Biasing: During thermal cycling, modules are subjected to forward-bias current to simulate operational stress found in field-deployed PV systems.

• Mounting Requirements:

  • Modules must be electrically isolated.
  • Allowance for free air circulation around module surfaces.
  • Proper sensor placement for accurate temperature measurement.

• Test Sequencing: Procedures can be performed individually or in combination with other environmental or non-environmental tests. Pre-conditioning steps, such as annealing or light soaking, may also be incorporated if required.

• Performance Evaluation:

  • Visual inspection to detect physical defects or anomalies.
  • Electrical performance and insulation integrity testing, pre- and post-exposure, to identify any degradation.

• Reporting: Detailed documentation of test specimen, setup, test parameters, observed effects, and deviations from standard methods.

Applications

ASTM E1171-15(2019) is widely used in the solar energy sector to:

• Performance Qualification: Helps manufacturers and certification bodies assess a module's durability under stress conditions defined in module qualification standards, such as IEC 61215 and IEC 61646.
• Product Development: Accelerates aging studies for new PV designs, materials, and construction methods.
• Quality Assurance: Verifies that production batches meet reliability and performance expectations for long-term outdoor exposure.
• Comparative Analysis: Facilitates evaluation and comparison of different PV module types and manufacturing processes under identical environmental stress conditions.

While this standard outlines rigorous testing procedures, it does not set acceptance or failure criteria. Decisions regarding acceptable levels of performance degradation are left to other relevant standards or project-specific requirements.

Related Standards

• ASTM E1036: Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells.
• ASTM E1462: Test Methods for Insulation Integrity and Ground Path Continuity of Photovoltaic Modules.
• ASTM E1799: Practice for Visual Inspections of Photovoltaic Modules.
• IEC 61215: Crystalline Silicon Terrestrial Photovoltaic (PV) Modules - Design Qualification and Type Approval.
• IEC 61646: Thin-Film Terrestrial Photovoltaic (PV) Modules - Design Qualification and Type Approval.
• ASTM E772: Terminology of Solar Energy Conversion.

Practical Value

Implementing ASTM E1171-15(2019) helps organizations strengthen their PV module reliability assessments, reducing the risk of field failures and supporting compliance with international solar module qualification standards. With clear guidelines for environmental stress testing, this standard is essential for producers, laboratories, and regulators committed to advancing solar technology and ensuring long-term energy performance.

Keywords: photovoltaic modules, environmental testing, thermal cycling, humidity-freeze, damp heat exposure, solar energy, ASTM E1171-15, PV module reliability, accelerated aging, IEC 61215, IEC 61646.

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: E1171 − 15 (Reapproved 2019) An American National Standard
Standard Test Methods for
Photovoltaic Modules in Cyclic Temperature and Humidity
Environments
This standard is issued under the fixed designation E1171; 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.
1. Scope priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 These test methods provide procedures for stressing
1.9 This international standard was developed in accor-
photovoltaic modules in simulated temperature and humidity
dance with internationally recognized principles on standard-
environments. Environmental testing is used to simulate aging
ization established in the Decision on Principles for the
of module materials on an accelerated basis.
Development of International Standards, Guides and Recom-
1.2 Three individual environmental test procedures are de-
mendations issued by the World Trade Organization Technical
fined by these test methods: a thermal cycling procedure, a
Barriers to Trade (TBT) Committee.
humidity-freeze cycling procedure, and an extended duration
damp heat procedure. Electrical biasing is utilized during the
2. Referenced Documents
thermal cycling procedure to simulate stresses that are known
2.1 ASTM Standards:
to occur in field-deployed modules.
E772Terminology of Solar Energy Conversion
1.3 These test methods define mounting methods for mod-
E1036Test Methods for Electrical Performance of Noncon-
ules undergoing environmental testing, and specify parameters
centrator Terrestrial Photovoltaic Modules and Arrays
that must be recorded and reported.
Using Reference Cells
E1462Test Methods for Insulation Integrity and Ground
1.4 These test methods do not establish pass or fail levels.
Path Continuity of Photovoltaic Modules
The determination of acceptable or unacceptable results is
E1799Practice for Visual Inspections of Photovoltaic Mod-
beyond the scope of these test methods.
ules
1.5 Any of the individual environmental tests may be
2.2 IEC Standards:
performed singly, or may be combined into a test sequence
IEC 61215Crystalline Silicon Terrestrial Photovoltaic (PV)
with other environmental or non-environmental tests, or both.
Modules — Design Qualification and Type Approval
Certain pre-conditioning tests such as annealing or light
IEC61646Thin-FilmTerrestrialPhotovoltaic(PV)Modules
soaking may also be necessary or desirable as part of such a
— Design Qualification and Type Approval
sequence. The determination of any such sequencing and
pre-conditioning is beyond the scope of this test method.
3. Terminology
1.6 These test procedures are limited in duration and there-
3.1 Definitions—Definitions of terms used in this standard
fore the results of these tests cannot be used to determine
may be found in Terminology E7721.
photovoltaic module lifetimes.
3.2 Definitions of Terms Specific to This Standard:
1.7 The values stated in SI units are to be regarded as 3.2.1 module ground point, n—the terminal or lead identi-
standard. No other units of measurement are included in this fied by the manufacturer as the grounding point of the module.
standard.
4. Significance and Use
1.8 This standard does not purport to address all of the
4.1 The useful life of photovoltaic modules may depend on
safety concerns, if any, associated with its use. It is the
their ability to withstand repeated temperature cycling with
responsibility of the user of this standard to establish appro-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
These test methods are under the jurisdiction of ASTM Committee E44 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Solar, Geothermal and Other Alternative Energy Sources and are the direct Standardsvolume information, refer to the standard’s Document Summary page on
responsibility of Subcommittee E44.09 on Photovoltaic Electric Power Conversion. the ASTM website.
Current edition approved April 1, 2019. Published April 2019. Originally Available from International Electrotechnical Commission (IEC), 3 rue de
approved in 1996. Last previous edition approved in 2015 as E1171–15. DOI: Varembé, Case postale 131, CH-1211, Geneva 20, Switzerland, http://www.iec.ch.
10.1520/E1171-15R19.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1171 − 15 (2019)
varying amounts of moisture in the air. These test methods 5.2.3 Provisions for monitoring and recording the chamber
provide procedures for simulating the effects of cyclic tem- temperature and relative humidity throughout the environmen-
perature and humidity environments. An extended duration tal testing shall be provided.
dampheatprocedureisprovidedtosimulatetheeffectsoflong
5.3 Temperature Measurement Equipment—An instrument
term exposure to high humidity.
or instruments used to measure module temperature during the
4.2 The durations of the individual environmental tests are environmental testing with a resolution of at least 0.1 °C, and
specified by use of this test method; however, commonly used a total error of less than 62 °C of reading.
durations are 50 and 200 thermal cycles, 10 humidity-freeze 5.3.1 Temperature sensors suitable for the test temperature
cycles, and 1000 h of damp heat exposure, as specified by range, such as thermocouples or thermistors, shall be attached
module qualification standards such as IEC 61215 and IEC to the portions of the modules likely to exhibit the longest
61646. Longer durations can also be specified for extended thermal time constant. For flat-plate modules, attach the
duration module stress testing.
sensors near the middle of the front or back surfaces of the
modules.
4.3 Mounting—Test modules are mounted so that they are
5.3.2 If more than one module of identical design and
electrically isolated from each other, and in such a manner to
construction is tested simultaneously, it is not necessary to
allow free air circulation around the front and back surfaces of
monitor the temperature of all identical modules.
the modules.
5.4 Test Frame—Aframeinsidetheenvironmentalchamber
4.4 Current Biasing:
which supports the test modules during the test procedures.
4.4.1 During the thermal cycling procedure, test modules
5.4.1 Itisnotrequiredtomountthetestmodulesatanangle
are operated without illumination and with a forward-bias
such as when modules are installed as part of an array; they
current equal to the maximum power point current at standard
may be mounted vertically to facilitate testing multiple mod-
reporting conditions (SRC, see Test Methods E1036) flowing
ules inside the environmental chamber.
through the module circuitry.
5.4.2 The test modules shall be mounted in a manner that
4.4.2 The current biasing is intended to stress the module
allows free air circulation around the modules.
interconnectionsandsolderbondsinwayssimilartothosethat
5.4.3 The test frame should be constructed such that corro-
are believed to be responsible for fill-factor degradation in
sionofthetestframeduringtheenvironmentaltestingdoesnot
field-deployed modules.
adversely affect the test modules.
4.5 Effects of Test Procedures—Data generated using these
5.5 Current-Biasing Power Supply—A dc power supply
test methods may be used to evaluate and compare the effects
capable of operating a test module at a point on the dark
of simulated environment on test specimens. These test meth-
forward current-voltage curve equal to the maximum power
ods require determination of both visible effects and electrical
current at SRC during the thermal cycling procedure.
performance effects.
5.5.1 Provisionsmustbemadeforremovingthecurrentbias
4.5.1 Effects on modules may vary from none to significant
when the module temperature is less than 20 °C.
changes. Some physical changes in the module may be visible
5.5.2 Thecurrentbiasingpowersupplyshouldbecapableof
when there are no apparent electrical changes in the module.
setting a voltage compliance limit equal to 1.25 times the
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