The durability of intumescent coatings is one of the most important factors in modern building safety. A groundbreaking 2024 study published in the Fire Safety Journal by the Federal Institute for Materials Research and Testing (BAM) in Germany has provided new scientific insight into how these coatings age and how their fire protection performance can be ensured for decades.
Titled “Durability of Intumescent Coatings and Recommendations for Test Concepts for a Working Life of More Than 10 Years,” the study proposes a new framework for testing intumescent coating durability—with the goal of extending certified working life from 10 to as many as 25 years.
For IFTI, this research directly supports the company’s long-standing approach to long-term passive fire protection through the selection of high-performance coatings, proper application, and structured inspection programs.
Key Findings on Intumescent Coating Durability
The research team examined both water-based and epoxy-based intumescent coatings using a combination of accelerated and natural weathering to simulate years of real-world exposure. Their findings are crucial for the construction, oil and gas, and industrial sectors that rely on these systems to safeguard structural steel:
- Current European test standards assume a 10-year lifespan but lack criteria for extending certification to 25 years.
- Water-based coatings are susceptible to high humidity and water exposure without a topcoat, resulting in surface blistering and reduced thermal performance.
- Epoxy-based coatings demonstrate outstanding long-term durability, showing virtually no performance loss after multiple extended weathering cycles.
- Ageing is nonlinear and unpredictable, often accelerating once physical or chemical thresholds are reached.
- Combined testing and maintenance approaches—artificial weathering, field monitoring and stricter assessment thresholds—are necessary to validate true long-term performance.
How Intumescent Coatings Age
The study’s experimental design simulated climatic exposures, such as UV radiation, humidity cycling, freeze–thaw events, and acid pollutants—conditions typical of steel construction environments.
The findings confirm that moisture is the most detrimental factor affecting the durability of intumescent coatings. Water intrusion causes chemical leaching of reactive ingredients such as ammonium polyphosphate (APP) and melamine, thereby weakening the intumescent reaction that forms the protective foam barrier in a fire.
In water-based systems, this process produced visible cracks, discoloration, and swelling under long-term exposure to humidity. Even when coatings appeared visually intact, thermal analysis revealed that insulation performance had deteriorated—a hidden threat that can only be detected through scientific testing.
Epoxy-based coatings, however, remained structurally sound even after extended cycles equivalent to decades of weathering. While they exhibited mild surface yellowing and fine cracking, their fire resistance and char structure remained stable. This makes epoxy formulations ideal for outdoor or industrial applications where coatings must endure heat, moisture and mechanical stress.
Extending the Working Life of Intumescent Paint Beyond 10 Years
Under the current European testing framework (EAD 350402-00-1106), intumescent coatings are assessed for a 10-year working life. The BAM report argues that simple time-based extrapolation—for example, doubling test duration to claim 20 years of protection—is not scientifically sound.
Instead, the study proposes a multi-layered verification model that combines:
- Extended artificial weathering beyond standard exposure cycles
- Tighter performance limits, reducing acceptable performance loss from 15% to 10%
- Severe environmental simulation, including high humidity, UV and freeze–thaw scenarios
When these approaches are combined, the study concludes that 25-year durability can be scientifically validated. In fact, some epoxy-based products have already achieved European Technical Assessments (ETAs) confirming 25-year performance under this model.
This rigorous testing method ensures that coatings not only meet laboratory benchmarks but also perform reliably in the environmental conditions of large-scale construction and infrastructure use.
Implications for IFTI and the Fireproofing Industry
For IFTI, the study reinforces what years of practical experience already demonstrate: the durability of intumescent coatings depends on the entire protection system, not just the chemistry of the coating. Our team already implements many of the report’s recommendations as standard practice:
- Specifying epoxy or hybrid coatings for exposed steel and industrial structures
- Ensuring proper surface preparation and primer compatibility for long-term adhesion
- Applying protective topcoats to water-based coatings in humid or semi-exposed environments
- Conducting scheduled inspections and maintenance, identifying early signs of microcracking or blistering before they compromise performance
The Science Behind Long-Term Durability
One of the study’s most significant insights is that coating degradation is nonlinear and product-specific. Certain mechanisms—such as oxidation or binder fatigue—can progress slowly over years, whereas others, such as microcrack propagation or delamination, may occur rapidly once triggered by moisture or heat.
IFTI’s expertise in both application and post-installation monitoring provides the scientific accountability that ensures these coatings remain effective well beyond standard test periods. The company integrates manufacturer data, environmental conditions and inspection reports to predict and prevent early coating failure—bridging the gap between laboratory testing and real-world performance.
IFTI: Applying Research to Real-World Protection
The 2024 BAM study demonstrates that intumescent coating durability is a complex, measurable science—and one that can be managed through research-backed design, application and maintenance. IFTI continues to manufacture the best products in passive fire protection, applying verified materials and proven methodologies to help clients meet or exceed durability expectations. Whether for a new high-rise development, energy facility or retrofit project, IFTI ensures that every intumescent coating is applied to last—safely, effectively and in compliance with global testing standards.
Connect with our team of specialists to discuss your structure’s long-term fire safety and durability.