Background
Outdoor exposure tests for assessing material weatherability began in the early 1900s. By 1908, ASTM Committee D-1 and the Paint Manufacturer’s Association utilized outdoor paint exposures. The method evolved from a 45-degree south-facing rack to a single-axis, follow-the-sun rack, and later included mirrors for sunlight concentration.

The Q-Trac Natural Sunlight Concentrator
The Q-Trac is a dual-axis accelerated natural weathering tester that tracks the sun and adjusts for seasonal changes. It uses mirrors to concentrate sunlight onto specimens, providing effective outdoor acceleration with natural sunlight. It operates in Arizona but can simulate various environments, such as South Florida, with additional features like ultra-pure water spray.

Concentrating Natural Sunlight
The Q-Trac uses a Fresnel concentrator with 10 flat mirrors to focus sunlight onto a target board. The mirrors are highly reflective and regularly cleaned to maintain efficiency. The device automatically tracks both the azimuth and altitude of the sun, ensuring optimal sunlight concentration.

Specimen Mounting & Cooling
Specimens are mounted on a target board with specific size limitations. An air cooling system prevents overheating by directing air across the specimens. In case of power or airflow loss, a fail-safe mechanism prevents overheating by moving the concentrator out of focus.

Operating Conditions
The Q-Trac requires clear, sunny conditions with minimal atmospheric moisture, making Phoenix, Arizona an ideal location. It operates only during periods of bright sunshine, with direct beam radiation needing to exceed 75% for effective operation.

Simulating Moisture
Water spray cycles simulate end-use environments, using purified water to avoid contamination. The Q-Trac can simulate South Florida conditions with specific spray cycles, such as Spray-1 for building materials and Spray-2 for coatings.

Timing a Test
Tests can be timed based on changes in control specimens or accumulated UV exposure. The Q-Trac typically produces UV exposure equivalent to five years of Florida testing in one year. Radiant exposure is calculated using solar tracking devices equipped with radiometers.

Summary of Popular Q-Trac Test Cycles
Various test cycles are available, such as Desert Days with sunlight only and Spray-1 with daytime and nighttime water sprays, each aligning with specific ASTM and ISO standards.

Overview: The document outlines the procedures and standards for accelerated outdoor weathering tests using the Q-Trac Natural Sunlight Concentrator. It provides detailed methodologies for simulating various environmental conditions to evaluate the durability of materials.

Specifications: The Q-Trac device is a dual-axis system that tracks the sun and concentrates sunlight onto test specimens, significantly accelerating UV exposure compared to natural conditions. It is primarily operated in Phoenix, AZ, due to optimal climate conditions.

Test Procedures: The document describes different cycles and procedures for testing, including water spray and freeze-thaw cycles. Specific ASTM and ISO standards are referenced, such as ASTM G90, ASTM D4141, and ISO 877, which guide the testing processes.

Environmental Conditions: The Arizona site is characterized by high solar energy and specific temperature and humidity profiles, which are crucial for the testing environment.

Recommendations: It is recommended to combine accelerated testing with natural exposures in Florida and Arizona to obtain comprehensive data on material durability. This approach helps in making informed predictions about product longevity.

Contact Information: The document provides contact details for Q-Lab facilities in Florida and Arizona, where these testing services are available.