Determining Pass/Fail Requirements: What You Should Look For When Testing
Blog
Last Updated 2025
Understanding a material or product's potential failure modes is essential, whether you're testing for quality control, trying to qualify for a particular spec, or evaluating product longevity. Q-Lab's comprehensive testing equipment and services help manufacturers identify and prevent common material failures before they reach the field.
Understanding Material Failure Types
Material degradation rarely happens overnight. Through accelerated testing, you can identify potential failures in weeks rather than waiting months or years for real-world data, though long-term outdoor exposures are still the best way to generate realistic performance data. Here's what to watch for when evaluating your products' durability.
Weathering-Related Failures
Visual Appearance Changes
- Color change and fading: Perhaps the most visible failure mode, affecting brand perception and product aesthetics
- Gloss loss: Surfaces losing their shine can indicate surface degradation
- Chalking: The formation of loose powder on coated surfaces signals coating breakdown
- Yellowing: Particularly important for polymers and clear coatings exposed to UV light
Structural Degradation
- Cracking: Surface or deep cracks that compromise material integrity
- Crazing: Fine surface cracks creating a spider-web pattern
- Hazing: Loss of transparency in clear materials
- Peeling and delamination: Coating separation from substrates
- Blistering: Bubble formation beneath coatings or surfaces
Physical Property Loss
- Embrittlement: Materials becoming brittle and prone to failure
- Strength loss: Reduction in tensile strength and structural integrity
- Warping: Dimensional changes affecting fit and function
- Oxidation: Chemical degradation of material surfaces, sometimes related to corrosion.
Corrosion-Related Failures
Rust (Corrosion) Formation
- General or free rusting: Widespread surface corrosion
- Spot rusting: Larger, isolated rust areas
- Pinpoint rusting: Small, localized rust spots
- Scab rust: Rust formation along scribes or damaged areas
- Rust creepage: Corrosion spreading beneath coatings
Coating Performance Failures
- Blistering: Osmotic pressure causing coating delamination
- Adhesion loss: Coating separation from the substrate
- Undercutting at scribe marks: Corrosion spreading from intentional damage points
The Benefits of Accelerated Weathering and Corrosion Testing
Accelerated Weathering Testing
QUV fluorescent UV testers and Q-SUN xenon arc chambers simulate the three main forces of weathering - sunlight, heat, and moisture - in controlled laboratory conditions. These systems can reproduce many of the weathering failure modes listed above that occurs over months or years outdoors, in just days or weeks. Q-Lab offers these weathering test instruments for use in your own facility, as well as offering Testing Services at our accredited accelerated laboratories in Florida and Germany.
QUV accelerated weathering testers uses fluorescent lamps to simulate critical short-wave UV radiation, which is responsible for nearly all photodegradation of durable materials.
Q-SUN xenon arc chambers reproduce full-spectrum sunlight for more comprehensive material testing, particularly for applications requiring visible light simulation.
Cyclic Corrosion Testing
Q-FOG cyclic corrosion chambers provide the most realistic laboratory simulation of natural atmospheric corrosion. These systems can perform traditional salt spray testing, Prohesion tests, and complex automotive corrosion standards, accelerating years of outdoor corrosive damage in weeks of laboratory testing.
Outdoor Exposure Testing
Natural outdoor weathering at Q-Lab's benchmark locations in Florida and Arizona offers the most realistic prediction of product performance. Florida's subtropical environment delivers abundant sunlight, warm temperatures, and high moisture, while Arizona's desert conditions provide intense sunlight with low humidity—perfect for testing highly durable materials.
Q-Lab's outdoor exposure sites use different testing mechanisms—including the Q-TRAC natural sunlight concentrator and AIM Box systems—to deliver realistic, accelerated weathering data. The Q-TRAC uses a bank of mirrors and sun-tracking mechanisms to concentrate full-spectrum sunlight onto specimens, achieving up to five times the UV dosage of a typical Florida year and enabling earlier insights into long-lifetime material performance. The AIM Box is designed to simulate the harsh thermal and solar conditions experienced behind vehicle glass, making it ideal for automotive interior materials testing.
Weathering exposures at these sites are not only realistic; they are also accelerated due to the intense conditions at those sites, and are the best way to verify laboratory test results. Q-Lab also provides all users with climate data to enhance interpretation of materials durability test results.
Establishing Pass/Fail Criteria
Our team always encourages customers to set clear pass/fail criteria before they begin testing. The simplest type of weathering and corrosion testing is quality control testing - defined screening tests conducted for fixed intervals that generate clear pass/fail results. This approach helps manufacturers meet customer specifications, qualify new materials, support warranty claims, and more. Laboratories may also conduct qualification testing, typically to meet a customer performance requirement. With the support of outdoor data, accelerated testing can also provide correlative results, giving indications of real-world performance and developing material- and application-specific acceleration factors.
Who Determines What's Acceptable?
You define what constitutes failure for your specific application! There's no universal standard that declares when color change becomes unacceptable or how much gloss loss is too much. Pass/fail requirements are entirely determined by those conducting the test, whether that's your quality control team, engineering department, or customer specifications.
In rare cases, standardized test methods from organizations (such as ASTM, ISO, or SAE) provide pass/fail requirements, but most widely-used international test methods simply provide the test procedure rather than the duration or requirements for performance on evaluations.
Evaluation Methods
Q-Lab quantifies test results through comprehensive evaluation techniques including optical measurements (color change, gloss retention, visual appearance), physical testing (hardness, tensile strength, impact resistance, adhesion via cross-hatch, and knife peel methods), and visual evaluations. Following international standards from ASTM and ISO, Q-Lab's experts assess specimens for cracking, blistering, peeling, chalking, and corrosion using standardized rating scales under controlled lighting conditions.
Getting Started with Durability Testing
Whether you're ready to purchase testing equipment or prefer to send specimens to a test laboratory, Q-Lab's ISO 17025 accredited facilities in Florida, Arizona, and Germany offer comprehensive testing solutions. With over six decades of experience in material durability testing, Q-Lab makes testing simple, accessible, and actionable.
Ready to start testing? Contact our team today!
Frequently Asked Questions
Q: Who determines pass/fail requirements in weathering and corrosion testing?
A: Those conducting the test (quality control team, engineering department) determine pass/fail requirements, often to meet a customer requirements. In rare cases, standardized tests provide guidance on pass/fail requirements, but mostly these requirements are determined by those running the test.
Q: How does Q-Lab quantify test results?
A: Q-Lab quantifies test results through comprehensive evaluation techniques including optical measurements (color change, gloss retention, visual appearance), physical testing (hardness, tensile strength, impact resistance, adhesion via cross-hatch, and knife peel methods), and visual evaluations.
Q: What are the different failure modes in weathering?
A: Many different types of material degradation can be observed, but they typically fall into one of three classes: visual appearance changes, structural degradation, and physical property loss.
Q: What are the different failure modes in corrosion?
A: Likewise, a range of complex corrosion-related behavior happens in natural environments, but rust formation and coating performance failures represent some of the most common.