Understand Automotive Exterior Durability using SAE J2020
SAE J2020 is a standardized accelerated weathering test method used for evaluating automotive exterior materials under simulated sunlight, heat, and moisture. Using a fluorescent UV and condensation apparatus, such as the QUV accelerated weathering test chamber, the test helps to evaulate material performance in outdoor environments by measuring resistance to common forms of environmental degradation before real-world exposure.
Test Parameters
SAE J2020 requires specific test conditions in order to produce the most accurate and reliable results:
- Light Source
- UVB-313 fluorescent UV lamps are specified and used historically, although UVA-340 lamps are permitted by agreement
- Exposure Cycle
- 8 hours of UV exposure at 70 °C, 0.48 W/m2/nm @313 nm
- 4 hours of condensation at 50 °C
- Temperature Control
- Specimen temperature monitored using a black panel thermometer
- Moisture Exposure
- Condensation generated by heated water pan beneath surface
- Produces distilled water condensation on test surfaces
- Specimen Orientation
- Mounted parallel to lamps at fixed distance
- Periodic specimen repositioning required to ensure uniform exposure
You can find in-depth information on how to program the SAE J2020 test cycle into your QUV accelerated weathering tester by logging into your Q-Portal account.
Why Test to SAE J2020
Testing to SAE J2020 allows manufacturers to evaluate how automotive exterior materials will withstand long-term exposure to sunlight, heat, and moisture before they are used in real-world applications. By providing a controlled, accelerated simulation of harsh outdoor conditions, the standard helps identify potential durability issues, compare materials or suppliers consistently, and support material selection, validation, and quality assurance while reducing the risk of premature field failures.
Pros and Cons of SAE J2020
- Internationally-recognized test method
- SAE J2020 is used widely by a variety of automotive manufacturers, giving a historical basis of results for comparison
- Fast test results
- The use of high temperature (70 °C in UV) and UVB lamps can accelerate product breakdown in many cases, though results need to be evaluated with caution
- Hot condensation
- The 4-hour condensation steps at 50 °C provide the most realistic simulation of outdoor moisture
- UVB-313 lamp specification
- The use of UVB lamps may lead to accelerated degradation, but UVB lamps can cause material changes not actually seen in outdoor environments
- Low irradiance setpoint
- The irradiance specification of 0.48 W/m2 is less intense than comparable ASTM and ISO specs, which can lead to longer test times
- Artificial UV Spectrum
- At the end of the day, nothing beats the real thing! That's why we always encourage customers to combine accelerated laboratory testing with natural outdoor testing for the most accurate and reliable results
How Q-Lab Can Help
QUV Accelerated Weathering Tester
Q-Lab’s QUV accelerated weathering tester fully complies with SAE J2020. It is the simplest, most reliable, and easiest-to-use weathering tester available. With thousands of testers in use worldwide, it is the world's most widely-used weathering tester.
Testing Services
If a new tester is not part of the budget, we offer testing at either of our two accelerated laboratories – Florida or Germany. Both labs are ISO 17025 accredited to perform SAE J2020, using the very same QUV test chambers built at our manufacturing plant. In addition to accelerated weathering testing, our accelerated laboratories are accredited and qualified to perform a suite of different evaluations, including color change, gloss retention, visual evaluations, and much more.
Q-PANEL Standard Test Substrates
Q‑PANEL paint test substrates are the world’s most recognizable and widely-used standard test panels. Q‑Lab manufactures millions of panels each year for a variety of industries, most available immediately from stock.
More SAE J2020 Resources
Standards Tool
Review setup and performance information on key international and OEM test standards from ASTM, ISO, SAE, JIS, GB, and more.
Document Library
Browse Q-Lab’s extensive library of weathering testing literature and technical content.
Contact Q-Lab
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