What Is the Wavelength of UV Aging Testers?

UV testing, also known as UV aging testing, is a process designed to simulate and accelerate the aging effects of various environmental factors on products under real-world conditions. It is primarily aimed at plastic materials, with common aging mechanisms including light aging, humidity-heat aging, and hot-air aging. For outdoor products exposed to sunlight for extended periods, resistance to yellowing and aging tests are crucial. To predict a product's outdoor lifespan, UV aging tests are conducted. Since the intensity of UV radiation in laboratory settings is higher than natural sunlight, these tests can significantly reduce testing time and provide rapid insights into a product's outdoor durability.

Standard Group's UV aging testers offer three types of lamps for UV testing:

• UVA-340 Lamps: These lamps excel at simulating short-wave ultraviolet (UV) light in sunlight, covering the wavelength range from 365nm down to the solar cutoff at 295nm. They are mainly used for light aging tests on outdoor products.
• UVB-313 Lamps: These lamps emit short-wave UV light more intense than natural sunlight, accelerating material aging to the maximum extent. However, they may cause unrealistic damage to certain materials. UVB-313 lamps are primarily used for quality control, research and development, or testing highly weather-resistant materials.
• UVA-351 Lamps: These lamps simulate the effects of sunlight passing through window glass indoors, making them highly useful for testing indoor materials.

Which Products Require UV Testing?

UV testing is of significant importance and is widely applied to plastics, lamps, paints and inks, resins, printing and packaging, aluminum profiles, automotive and motorcycle industries, cosmetics, and more.

What Are the UV Aging Test Standards?

1. General Standards:
   • ASTM D 4459, ASTM G 154, ISO 4892, IEC 60068, ISO 4892-1, ASTM G151, ASTM G154, JISD0205, SAEJ2020
2. Plastics:
   • ISO 4892-3, ANSI C57.12.28, ANSI A14.5, ASTM D4329, ASTM D4674, ASTM D5208, ASTM D6662, DIN 53384, UI K 3750, UNE 35 104
3. Coatings:
   • ASTM D3794, ASTM D4587, FED-STD-141B, GM 9125P, JIS K 5600-7-8, ISO 11507, ISO 20340, M598-1990, NACE TM-01-84, NISSAN M0007, PrEN 927-6
4. Textiles:
   • AATCC TM 186, ACFFA GUIDELINE
5. Roofing Materials:
   • ANSI/RMA IPR-1-1990, ASTM D4799, ASTM D4811, ASTM D3105, ASTM D4434, BS D5019, BS 903: PART A54, CGSB-37.54-M, DIN EN 534
6. Printing Inks/Art Materials:
   • ASTM D3424, ASTM F 1945

Which Instrument Brand Is Recommended for UV Testing?

The QUV ultraviolet aging tester is the most widely used UV aging testing machine globally. It provides reproducible and reliable aging test data in just a few weeks or months. Its short-wavelength UV light and condensation cycles realistically simulate the damaging effects of sunlight, dew, and rain on materials. Hummel has been representing Standard Group's aging test products for 40 years. For inquiries, please call 400-6808-138.

Common Misunderstandings About UV Testing

How Many Outdoor Days Does 1 Day of UV Testing Equate To? How Many Years Does 2000 Hours of UV Testing Equate To?

Theoretically, it is impossible to calculate outdoor exposure time by multiplying the hours in an aging tester with a single conversion factor. The issue is not the lack of precise aging testers; even with the most sophisticated or expensive equipment, such a "magic coefficient" remains elusive. The primary challenge lies in the inherent variability and complexity of outdoor environments. The relationship between tester exposure and outdoor exposure is influenced by numerous variables, including:

1. Geographic latitude of the exposure site (closer to the equator means stronger UV radiation)
2. Altitude (higher altitudes mean stronger UV radiation)
3. Local geographical features (e.g., wind drying samples, proximity to water bodies facilitating dew formation)
4. Year-to-year weather variations (leading to differences in aging effects at the same location)
5. Seasonal changes (e.g., winter exposure may be only 1/7th of summer exposure)
6. Sample orientation (5° south-facing or vertical north-facing)
7. Sample insulation (back-plated outdoor samples often age 50% faster)
8. Tester operating cycles (hours of light and moisture)
9. Tester temperature (higher temperatures accelerate aging)
10. Material properties and spectral power distribution (SPD) of the light source

Logically, discussing conversion factors between accelerated aging hours and outdoor exposure months is meaningless. One condition is constant, while the other varies. Seeking such a factor often exceeds the scope of valid data. Aging data is relative.

Nevertheless, valuable weather resistance data can still be obtained from accelerated aging testers. However, it is essential to recognize that this data is relative, not absolute. What you can reliably gain from laboratory tests is a material's weather resistance rating compared to others.

The same applies to Florida exposure tests. Comparing 1 year of outdoor south-facing 5° "black box" exposure to 1 year of indoor or in-car exposure is impossible. Even outdoor tests only provide information on relative service life.

However, comparative data is powerful. For instance, a minor formulation change might double a material's weather resistance. You might find that some seemingly identical materials from suppliers age rapidly, most within moderate periods, and only a few after prolonged exposure. You might discover an inexpensive material with the same weather resistance as a standard material that normally lasts 5 years.

A clear example of relative data's utility involves a coating manufacturer developing a new varnish. Initial QUV tests showed severe cracking within 200-400 hours, much faster than conventional coatings. After 3 years of continuous formulation improvement, several coatings withstood 2,000-4,000 hours of QUV exposure, significantly outperforming conventional coatings. Subsequent parallel tests in Florida showed a similar 10:1 improvement in weather resistance.

If coatings chemists had waited for Florida data before changing formulations, they might still be in the early stages of development, and the coating would not have achieved commercial success.

If you insist on finding an approximate acceleration factor, it must be discovered empirically. Although a universal factor is impossible, hundreds of labs have developed their own "acceleration factors" by comparing accelerated and outdoor tests. However, these factors apply only to:

1. Specific test materials
2. Specific tester cycles and temperatures
3. Specific outdoor exposure sites and sample installation methods

If your material has outdoor exposure history, you can determine your factor within months. Without such experience, you can use reference materials with outdoor test data.