A seal’s true value isn’t in how it looks on day one, but in whether it still protects your enclosure years later under heat, moisture, and mechanical stress. This Enclosure Institute™ article breaks down five core tests engineers can use to validate long-term gasket reliability: compression set, stress relaxation, thermal cycling, chemical resistance, and IP ingress protection.
Check out the extended blog on the Rogers website, How To Validate Enclosure Seal Reliability Through 5 Tests, and the video below.
*Disclaimer: The Enclosure Institute™ is a free educational resource created by Marian, Inc. and Rogers Corporation to help engineers navigate enclosure sealing with expert guidance.
Predicting Failure Points to Design for Success
Enclosure gaskets and seals are best validated through reliability testing that predicts potential failure points before they occur. Direct long-term field testing is rarely practical, since products are expected to perform for years in demanding environments.
Instead, engineers use controlled reliability tests to replicate real-world stressors such as temperature cycling, pressure fluctuations, mechanical loads, and chemical exposure. These simulations reveal how a gasket will perform over time and identify the conditions most likely to cause seal failure or performance degradation.
Reliability Test Methods
1. Compression Set (C-Set) Testing
Compression set testing determines a gasket’s ability to recover its original thickness after prolonged compression, making it one of the most important predictors of seal reliability. According to ASTM D3574 and ASTM D1056, materials are typically compressed to 50% of their original thickness and held under load for a specified time at a controlled temperature.
After the hold period, the sample is allowed to relax before its final thickness is measured. To better replicate application conditions, additional factors such as heat aging can be applied to the test environment to simulate long-term performance. In general, a high-quality gasket material should recover to within 5% of its original thickness, ensuring consistent sealing performance throughout its service life.
2. Stress Relaxation Testing
Stress relaxation testing measures how well a gasket maintains sealing force under constant compression over time. This test is essential because a gasket may initially seal well but lose its effectiveness as internal stresses dissipate.
According to ASTM D6147, materials are compressed to a defined deflection, and the force is measured at regular intervals to track loss of stress. By simulating long-term compression in an enclosure, stress relaxation testing helps engineers predict seal longevity and determine whether a material can maintain sufficient force to prevent leaks throughout the product’s service life.
For long-term, reliable sealing, engineers will want foam materials that retain as much of the original compression force as possible.
3. Thermal Cycling
Thermal cycling evaluates how a gasket performs when repeatedly exposed to temperature extremes, ensuring it can maintain sealing integrity under real-world operating conditions. Materials expand and contract at different rates, which can compromise a seal if the gasket cannot adapt.
Testing involves exposing the gasket or enclosure assembly to alternating high and low temperatures, often in controlled cycles that reflect the intended application. By analyzing leakage, dimensional changes, or material degradation during these cycles, engineers can predict whether a gasket design will maintain reliable performance across the full temperature range of the end-use environment.
4. Chemical Resistance Testing
Chemical resistance testing evaluates how well a gasket material withstands exposure to liquids and gases, making it a critical predictor of long-term reliability.
Engineers often measure the percentage reduction in tensile strength to quantify material deterioration. This data helps determine whether a gasket can maintain performance in environments where contact with fuels, solvents, coolants, or cleaning agents is expected.
5. Ingress Protection (IP) Testing
Ingress Protection (IP) testing verifies that an enclosure seal prevents the penetration of dust, water, and other contaminants in accordance with IEC 60529 standards.
Each IP rating corresponds to a specific level of resistance, such as protection against dust (IP5X or IP6X) or water intrusion from jets, sprays, or immersion (IPX4 through IPX8). Get more information about IP ratings in our blog, "Ingress Protection Rating (IP Rating) Explained".
Testing involves subjecting the enclosure to controlled environmental conditions, such as pressurized water spray or dust chambers, to confirm compliance with the target IP code. For electronics housings, medical devices, and EV battery packs, IP testing provides direct validation that gasket and seal designs meet the environmental protection requirements of their intended application.
Benefits of Reliability Testing
Only through targeted reliability testing can engineers move from assumption to confidence, ensuring their enclosures resist leaks, downtime, and failures long after installation.
- Compliance to industry standards & regulations
- Help engineers validate designs
- Confirm good design choices, or alert engineers to potential weaknesses
- Help prevent downtime and unscheduled maintenance
- Ensure safety and performance under worst-case scenarios
Read the extended blog on Rogers’ website here.
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Coming Up Next in Module 4 of the Enclosure Institute™
- Fabrication Considerations
- Venting Considerations for Gasket Design
- Gasket Design for Outdoor Enclosure's
- Die-cut foam gaskets vs. Form-in-place solutions
- And much more!
Working on an enclosure application and not sure where to start or currently knee-deep in an active project and not sure what's next? Contact us and we'll put you in touch with a Sales Engineer in your area. Our technical teams can walk you through all the important considerations to make sure your application is ready to go to market without issues.
