In most people’s impressions, steel is very hard and strong, and is almost fearless in any situation.
When a fire occurs, the real dangers often lie hidden from people’s view. Steel is a key material in modern construction, yet it becomes vulnerable under high temperatures. When the temperature reaches 550°C, the load-bearing capacity of steel will drop significantly by 50%. Moreover, during a building fire, the temperature can easily reach 800-1000°C. This means that unprotected steel structures may yield and deform within 30 minutes, ultimately leading to the collapse of the building. This is not a conjecture but a fact revealed by materials science. In accordance with China’s Code for Fire Protection Design of Buildings (GB50016-2014) and the standards of other countries, the beams and columns of Class I buildings need to be able to withstand fire for 120 minutes and 180 minutes respectively – this is to ensure that there is sufficient time for people to escape and for the fire to be controlled.
Chapter 1: Critical Temperature: The Balance Between Load-Bearing Capacity and Temperature
The failure of a steel structure is actually a process in which a delicate balance is broken:
Strength Reduction: The strength of steel begins to decrease noticeably at around 350°C. 550°C is an important threshold (with the load-bearing capacity dropping to 50%), and at approximately 620°C, it is close to complete failure.
Influence of Load: The critical temperature is not fixed. It is related to the weight borne by the component – the greater the load, the more likely the steel is to fail. A fully loaded column is more prone to collapse than an unloaded one.
Influence of Time: Exposed steel heats up rapidly in a fire. Within 30 minutes, the internal temperature of the steel will exceed the critical point, resulting in the loss of strength and stiffness, plastic deformation, and ultimately the collapse of the structure.
Chapter 2: JOINBLING®: A Standard-Compliant Fire Protection System
To cope with high temperatures, reliable engineering solutions are required. The steel structure fireproof cladding system is such a precision protection system. Its function is to slow down the rate of heat transfer to the interior of the steel, ensuring that the temperature of the steel remains below the critical point (usually 550°C-620°C) within the specified time (EI 30 to EI 120 and even I 180).
excellent Quality: The JOINBLING® system is strictly tested and certified in accordance with international standards such as EN 14306 and has obtained the CE mark. This indicates that its performance is reliable and can provide protection for projects around the world.
Protection Principles: The fireproof panels used in this system have the following functions:
Heat Absorption: The material absorbs a large amount of heat.
Physical Barrier: It forms a thermal insulation layer to prevent heat transfer.
Chemical Reaction: Some materials undergo endothermic reactions at high temperatures, consuming energy.
Customized Protection: The thickness of the protective layer is not fixed but is calculated based on the following factors:
Fire Resistance Time (Rf): Determined according to the purpose, scale, and risk level of the building.
Critical Temperature (θ_cr): Calculated by structural engineers based on the load (usually 500-600°C).
Section Factor (Hp/A): Reflects the sensitivity of the component to temperature. Thick steel heats up slowly, while thin steel heats up quickly.
Independent Verification: Third-party evaluation reports based on standard tests (such as EN 13381) will comprehensively consider the above factors and provide references for thickness.
Chapter 3: Concrete Structures: Easily Overlooked Risks and Protection
Concrete is often considered fire-resistant, but it also has its own risks:
Problems with Concrete: At high temperatures ranging from 200°C to 800°C, concrete will crack and dehydrate, leading to a reduction in strength.
Problems with Steel Reinforcement: Concrete can slow down the heating of steel reinforcement, but if the concrete protective layer is too thin or a severe fire occurs, spalling may happen, resulting in the exposure of the steel reinforcement.
Situations Requiring Protection:
The thickness of the steel reinforcement protective layer is insufficient.
There is a risk of spalling.
There is a need to improve the strength of the concrete itself.
Solutions:
Equivalent Thickness: The fireproof layer can provide the same thermal protection effect as the concrete protective layer.
Spalling Inhibition: Special materials can control steam pressure, enhance surface strength, and prevent spalling.
Customized Solutions: The required thickness depends on the required thickness of the protective layer, the fire-exposed surface of the component, the fire resistance time, and the adhesion of the material.
Chapter 4: Structural Protection: Life, Property, and Social Responsibility
Professional fire protection for steel or concrete structures is of great significance:
Ensuring Life Safety: 120/180 minutes of fire resistance time can provide valuable time for personnel evacuation and fire rescue.
Protecting Important Assets: Cultural relics in museums, rare books in libraries, core servers in data centers, and medical equipment in hospitals – all these important items rely on the stability of the building structure.
Enhancing Building Stability and Sustainability: Buildings that do not collapse can be repaired, thereby avoiding the costs and environmental burdens caused by reconstruction, which is beneficial to the sustainable development of cities.
Conclusion: Meeting European Standards to Ensure Safety
Understanding the vulnerability of steel at 550°C and recognizing the risk of concrete spalling is the foundation of modern building safety. Choosing a protection system verified by international standards can provide important safety guarantees for buildings.
Respect for standards, trust in certifications, and attention to details are the guarantees of safety and quality. When designing and constructing buildings, adopting protection schemes that comply with European standards such as EN 14306 is a responsible investment in life, cultural heritage, and sustainable development. Let fire protection technology be the guardian of buildings.
