On November 21, 2022, a major fire broke out at Kaixinda Trading Co., Ltd. in Anyang, Henan, which remains a scar hanging over the field of construction safety in China. This particularly serious fire accident ultimately resulted in a tragic figure of 42 deaths and direct economic losses of up to 125 million yuan.

In this tragedy, the "weaknesses" of the building structure were exposed: the factory building involved was a two-story steel frame structure, and under the continuous baking of the high temperature caused by the fire, the steel quickly lost its strength, resulting in a large-scale collapse of the building in a very short period of time. Monitoring data shows that the fire engulfed the entire 11000 square meter building in just a few hours, leaving less than 10 minutes of golden time for internal personnel evacuation.

This is not an isolated case. In recent years, with the rapid construction of industrial plants, logistics warehouses, and large sports venues, steel structures have occupied half of the construction market due to their advantages of fast construction speed, large spatial span, and relatively low cost. However, 'fear of fire' is a fatal weakness inherent in this material. You may not know that the strength of ordinary steel will drop by 50% at a high temperature of 500 ℃; When the temperature rises to 1000 ℃, it will completely lose its load-bearing capacity. The temperature at an ordinary fire scene can often exceed 1300 ℃ in a short period of time. This means that steel structures without professional fire protection are like "ticking time bombs that collapse instantly" in the face of fire!

Steel structure: why is the "muscle" of modern architecture so fragile?

To understand the root cause of this disaster, we must first understand the physical properties of steel.

At room temperature, steel is the backbone of a building, tough and strong. But in the face of the raging fire, it appeared exceptionally delicate. Steel has extremely strong thermal conductivity, and once a fire occurs, heat will quickly be conducted through the steel components to the entire building structure. When the temperature reaches 350 ℃, 500 ℃, and 600 ℃, the strength and yield point of the steel will decrease by 30%, 50%, and 70%, respectively.

Imagine a steel frame factory weighing tens of thousands of tons, where the load-bearing columns and beams soften like candles in high temperatures, transforming the originally hard frame into noodles. This sudden change in physical properties often occurs within a few minutes without any warning signs. For those who are inside, the sudden collapse of the building means that the escape route is completely cut off, and the chances of survival are extremely low.

The on-site investigation report of the Anyang fire revealed a cruel reality: due to the lack of effective fireproof coating protection, the steel columns and beams of the factory quickly failed under the scorching fire, ultimately leading to the collapse of the roof and walls as a whole, trapping survivors under the ruins.

The 'invisible protective net' of life: the scientific principle of fireproof coating

Faced with the physical weakness of steel, humans are not helpless. Steel structure fireproof coating is the "invisible protective net" designed to solve this pain point.

Many people mistakenly believe that fire-resistant coatings are just a layer of ordinary paint, applied just to look good. In fact, it is the "passive fire protection system" of buildings and also the "last line of defense" of life.

1. The insulation mechanism of "attacking fire with fire"

High quality steel structure fireproof coatings (especially expansion type) contain special chemical components inside. When encountering flames and high temperatures, it does not burn or peel off like ordinary paint, but undergoes a wonderful "expansion carbonization" reaction. The coating will rapidly foam and expand, with a volume that can increase by dozens of times, forming a thick, sponge like black carbonized layer.

Although this carbonized layer appears fragile, it is actually an efficient thermal barrier. Its thermal conductivity is extremely low, which can effectively block flames from directly licking steel, greatly slowing down the speed of heat transfer to the steel. By sacrificing oneself and protecting the subject, fireproof coatings can control the heating rate of steel structures at an extremely low level.

2. Strive for the "golden escape time"

According to national standards and actual testing, steel structures coated with qualified fireproof coatings can extend their fire resistance limit from the original 15 minutes to 1.5 hours or even more than 3 hours.

What does this extra 90 to 180 minutes mean? For factory workers, this is the time for orderly evacuation from noisy workshops to safe areas; For firefighters, this is the window period for laying water hoses and conducting search and rescue operations deep into the fire scene; For the building itself, this is the key to avoiding overall collapse and preserving restoration value.

Legal red lines and industry standards: this is not a multiple-choice question

After experiencing countless bloody lessons, steel structure fire prevention is no longer an "optional configuration", but a "mandatory indicator" stipulated by law.

China's mandatory standards such as the "Code for Fire Protection Design of Buildings" (GB 50016) and "Fireproof Coatings for Steel Structures" (GB 14907) clearly stipulate that the fire resistance limit of load-bearing columns in civil buildings and factories is usually required to reach 2.0 hours to 3.0 hours; Steel beams and columns of high-rise buildings and important public buildings must be protected against fire.

This means that any newly constructed, renovated, or expanded steel structure building that is not coated with fire-resistant paint according to regulations, or whose thickness and performance of fire-resistant paint do not meet standards, is legally considered an "unqualified product" and a potential "murder weapon".

However, in the real construction market, in order to reduce costs, there are still many construction companies or contractors who have put "crooked ideas" into fireproof coatings:

Cutting corners and using inferior materials ": painting only a thin layer, or even only the surface to look good, while being lazy inside;

'Passing off inferior as good': using inferior and expired fireproof coatings, not only does it not expand when exposed to fire, but it also supports combustion;

False testing ": Obtaining qualified testing reports through improper means and passing the buck.

These actions are like planting a timed bomb in a building.

Awakening from Tragedy: Safety is Not 'Almost'

From the ruins of Anyang to the frequent factory fires in various places, every painful cost serves as a warning to us: in the field of building safety, there is no such thing as "similarity", only "practicality".

Each layer thickness of steel structure fireproof coating carries the weight of life. A big fire can destroy years of accumulated wealth, and taking preventive measures in advance is the most cost-effective 'safety investment'.

For business owners, the cost of fireproof coatings accounts for a negligible proportion of the total project cost, but the safety guarantee it brings is priceless. Choosing compliant and adaptable fire-resistant coatings for steel structures is not about cost, but about providing the building with a 'lifetime safety insurance' and giving employees a commitment to survival.

Life cannot withstand luck, and safety cannot be compromised. When we look up at those towering steel frame structures, may we see not only the glory of modern industry, but also the invisible 'invisible armor' that guards life.

Do you think the warning power of this article meets your expectations? If you need to adjust your tone for specific readers (such as factory owners, engineering supervisors), or want to add some specific "pit avoidance guidelines" and "inspection methods", feel free to let me know and I will help you optimize!