ASTM D4798 – Standard Practice for Accelerated Weathering Test Conditions and Procedures for Bituminous Materials – is a test used for simulating accelerated aging of bituminous roofing materials as part of our offering for sun exposure aging.
ASTM D4798 is a practice, not a test method. This means it is generic in nature and needs to be used in conjunction with another standard or more so that an actual test can be run. In this case, these additional documents would be for xenon-arc exposure practices ASTM G151 and ASTM G155.
Typically, when testing to this standard; thin films of bitumen are uniformly applied to aluminum panels. Shingles and similar products are cut to size and exposed to specified cycles of temperature, light, and water.
Typical Experimental Parameters
When performing ASTM D4798 the following test parameters need to be defined carefully:
- Lamp filters: exterior conditions
- Black panel temperature: 60 oC
- The lamp irradiance level:0,35W/(m2-nm) @ 340 nm
- Dry bulb temperature: 44 oC
- Cycle A or B
- Number of specimen of the same formulation: 3
- Specimen size: 2.75 X 5.5 inches
- Exposure duration
Our experts will be happy to assist you to get the best accelerated weathering test possible.
Uses and Factors to Be Considered:
When testing bituminous materials to ASTM D4798, it is not possible to obtain a precise correlation between accelerated and natural aging. For a detailed discussion on this limitation please read accelerated Weather-Ometer®️*.
The following factors will impact the time compression factor i.e. the aging rate:
- Geographical climatic variations
- Local weather variations
- Actual atmospheric pollutants
We also invite you to download our PDF on the true color measurement: What is the difference between the “true” color of an item and its “perceived” color (by the human eye)?
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*Weather-Ometer®️ is a registered trademark of Atlas Material Testing Technology LLC