QUV accelerated weathering test

The QUV Accelerated Weathering Test is a widely recognized laboratory method to simulate the damaging effects of sunlight, moisture, and heat on coatings and materials. By replicating years of outdoor exposure in just weeks or months, it helps manufacturers and quality assurance teams ensure that their products can withstand real-world environmental conditions.

Purpose of the Test

The QUV test evaluates the durability and weather resistance of coatings, paints, plastics, and other surface treatments. It provides critical insights into:

• Color stability
• Gloss retention
• Chalking, cracking, or blistering
• Loss of adhesion or mechanical properties

This test is especially valuable for industries such as automotive, aerospace, marine, architecture, and consumer products, where coatings must endure prolonged exposure to outdoor weather.

International Standard

The most relevant global standard is:

• ISO 4892-3 – Plastics: Methods of exposure to laboratory light sources – Part 3: Fluorescent UV lamps

Other related standards include:

• ASTM G154 – Standard Practice for Operating Fluorescent UV Lamp Apparatus for Exposure of Nonmetallic Materials
• ASTM D4587 – Accelerated Weathering of Paints by Fluorescent UV-Condensation Apparatus
• DIN EN ISO 16474-3 – Laboratory light sources – Fluorescent UV lamps

Working Method

Test Principle

The QUV test uses fluorescent UV lamps to reproduce the most damaging portion of sunlight (UV radiation) combined with moisture condensation and/or water spray to simulate dew and rain. This cyclic exposure accelerates natural weathering, providing reproducible and consistent results.

Procedure

1. Specimen Mounting
   • Coated panels or test samples are placed in the QUV chamber.
2. Light Exposure
   • Fluorescent UV lamps (commonly UVA-340 or UVB-313) emit radiation that mimics natural sunlight in the critical short-wavelength region.
   • Irradiance is controlled (e.g., 0.89 W/m² at 340 nm).
3. Moisture Simulation
   • Two primary methods are used:
     • Condensation: Water vapor condenses directly on specimens to simulate dew.
     • Water Spray: Periodic spraying mimics rain erosion.
4. Temperature Control
   • Black panel temperatures are typically maintained between 50°C – 75°C, depending on the cycle.
5. Cycle Repetition
   • Common cycles include 8 hours of UV light at 60°C followed by 4 hours of condensation at 50°C.
6. Exposure Duration
   • Varies by product specification: from 500 hours (3 weeks) to 2000+ hours to simulate months or years of outdoor exposure.
7. Evaluation
   • Visual inspection for color fading, gloss loss, cracking, or chalking.
   • Instrumental measurements such as ΔE color change or gloss retention provide quantitative data.

Applications

• Architectural paints and coatings
• Automotive coatings and plastics
• Industrial finishes and powder coatings
• Marine coatings and composites
• Consumer products exposed to sunlight (furniture, outdoor equipment, packaging)

Advantages of QUV Testing

• Reproducible and standardized simulation of UV, heat, and moisture damage
• Faster evaluation compared to outdoor exposure testing
• Allows comparative ranking of coating formulations
• Reduces the risk of premature product failure in service