The physical methodology behind a dependable fogging tester is straightforward: plastic or elastomeric materials are heated, releasing invisible gaseous vapors that turn back into a greasy liquid deposit upon contacting a cold glass surface. This represents the same physical condensation behavior observed when warm, airborne moisture contacts a cold boundary.
This accelerated laboratory test recreates the real-world challenge of cabin windshield cloudiness. The entire procedure relies on two highly controlled thermal phases managed by the Qualitest QT-FT1:
- Thermal Outgassing Phase (High-Temperature Liquid Bath): Heat acts as the primary driver of this entire physical reaction. When testing temperatures rise, the volume of drifting chemicals increases substantially. Evaluating vehicle cabin materials in test chambers shows that jumping from a standard room temperature of 25°C to a warm 60°C causes the volume of drifting chemicals to increase by anywhere from 3 to 36 times. That is exactly why the QT-FT1 features a highly stable heating bath that reaches up to 150°C with a razor-sharp thermal accuracy of ±0.5°C.
- Controlled Condensation Phase (Chilled Collection Plates): The chilled side of the testing machine is equally critical. If the temperature of the condensing plate fluctuates or is not cold enough, the gaseous chemicals will fail to stick properly, which completely compromises your final data. To eliminate that specific variable, the QT-FT1 utilizes a dedicated motorized compressor cooling system to hold the cooling plates perfectly steady anywhere from 10°C to 50°C with an exacting ±1°C accuracy.
Dual Analytical Evaluation Pathways
We evaluate the collected residue through two primary analytical avenues, which are controlled by the QT-FT1’s intuitive HMI+PLC operating system across its 6 independent testing stations:
- The Gravimetric Pathway (Weight-Based Measurement): The evaporated constituents are deposited onto a piece of aluminum foil, and the sample is weighed to determine the exact mass of the condensable constituents. Higher test temperatures typically yield an increased deposit mass.
- The Photometric Pathway (Light-Transmission Measurement): A concentrated beam of light is projected through a glass plate, and a gloss meter or hazemeter is used to evaluate the likelihood of a material to leave a light-scattering film. If you run the test hotter, make the plate colder, or run the test longer, the light transmission is reduced.
Standard Compliance
Because these testing standards require completely different heating levels, chilled plate settings, and testing timers, comparing their numeric scores is completely impossible. A heavy-duty analytical instrument like the QT-FT1 is built to accommodate several distinct global testing frameworks:
- DIN 75201-2011
- ISO 6452-2021
- ISO 17071-2006
- EN ISO 17071-2011
- SAE J1756-2006
Comparison of Standardized Methodologies
| Testing Approach | What We Are Actually Measuring | What Can Throw Off the Numbers | When to Use It |
|---|
| Gravimetric Method | The physical mass of the condensed chemical deposit on aluminum foil | Minor fluctuations in the heating bath temperature | Screening raw materials early in development |
| Photometric Method | Light transmission loss on a glass surface caused by the collected film | Chilled plate temperature drift and exposure time | Assigning a real-world visibility rating |
Having this level of certainty from a strictly controlled, accelerated condensation test is an essential requirement for evaluating materials destined for automotive or other vehicle interiors before they ever reach the assembly line.
