The Golden Rules of Steel Construction

Fireproof coating puts on “protective clothing” for steel structures

With the rapid economic development, China's construction steel structure has been more widely used and applied since the 1990s. Modern steel structure engineering is an important part of China's large-scale modern architecture. Because the steel structure has its own advantages of light weight, low foundation cost, suitable for soft foundation and easy installation, quick construction, short cycle, small construction pollution and good earthquake resistance, the steel structure building was listed as the promotion project by the former Ministry of Construction. However, in recent years, frequent fire accidents have occurred in steel structures. The CCTV new site fire incident has once again sounded the alarm for people.

According to Xue Fa, a senior expert of China Construction Metal Structure Association, the fire protection problem of steel structures has always been the focus of experts in the industry. China's steel structure building fire protection technology is not advanced in foreign countries. Currently widely used methods are: steel structure fire protection coating on steel The surface of the component plays a role in fire protection and heat insulation, prevents the steel from rapidly heating up in the fire and reduces the strength, and prevents the steel structure from losing its supporting ability and causes the building to collapse. At present, the research, production, promotion and application of fire protection coatings for steel structures have received increasing attention.

It is understood that after more than 20 years of development, China's fire-retardant coating production enterprises have begun to take shape, and the number of production enterprises has grown to more than 250. However, in a large number of fire-retardant coating production enterprises, the scale, management, and technical level of enterprises are uneven. Very few quality products. Among the numerous manufacturing enterprises, only half of the companies have passed the ISO9000 quality system certification. Relevant investigations have found that fire-retardant paint products sold on the domestic market generally suffer from several problems: low fire performance, easy to fall off, poor decoration, poor durability, and unstable quality.

At present, there are many steel structures in the country. In order to meet the requirements of fire protection, the owner must not use imported steel structure fire protection coatings. Although the imported fire protection coating can meet the fire protection requirements, the cost price of nearly 70,000 yuan and 1 ton has caused the builders to suffer. Words. For fire retardant coatings, the key lies in a reasonable formula and production process.

Anticorrosion of steel structure of building can not be ignored

After years of development, the steel structure construction industry is currently booming. However, due to the relative lag in the introduction of relevant laws, regulations, and standards, there have been many problems in steel structure construction in recent years, such as the number of occurrences in Zhejiang in 1998. Million square meters of light steel plant and individual grid structure collapsed; a grid structure project spanning 70 meters in a certain place suddenly collapsed after five years of use. In addition to the problems of design, production, and installation, the corrosion of steel structures is also a serious problem.

Xue Fa said that the owners, users, design and construction companies of steel structure projects all pay insufficient attention to the problems of steel structure protection, and they still remain in the traditional anti-corrosion technology. Due to improper selection of materials and construction processes, premature corrosion or damage to steel structures is often caused. At present, no matter how the owner, user or constructor of the project is used to detect the performance of the anti-corrosion coating at the time of construction, it is basically ignored. In addition, some project owners completely depend on plans. Before the project was started, no special anti-corrosion engineering experts were required to evaluate the project's overall anti-corrosion program. No professional anti-corrosion construction engineers or experts were assigned to strictly inspect the anti-corrosion coating. Handed over to the project supervisor. The engineering supervisor's understanding of corrosion protection is also based on plans. After the project is put into use, there is basically no inspection for anti-corrosion maintenance. There is also the expense of cutting down the anti-corrosion project regardless of the actual situation. All of these results in a significant reduction in the life span of the steel structure. The protection practices of various countries in the world against steel construction prove that the use of heavy anti-corrosion coating for anti-corrosion coating and fire protection anti-corrosion coating for fire protection and anti-corrosion coating are the most economical, effective, and simplest and most practical methods.

Long-term protection technology for building steel structures needs to be improved urgently

Xue Fa thinks that it is extremely important to use steel structure anti-corrosion technology, especially long-term anti-corrosion technology. The anti-corrosion design period is 30 years. Different anti-corrosion coatings are used according to different indoor and outdoor environments. In fact, the coating system is composed of two different structural coatings, including an electrochemically protected zinc-rich primer, and a scaly, natural cloud-iron-based, intermediate paint that functions as a skeleton support and provides excellent shielding performance. Epoxy topcoats have good adhesion, wear resistance, water resistance, and chemical resistance, which are far from reach for other types of coatings.

At present, all countries in the world have paid a certain amount of attention to the issue of building fire protection and have issued corresponding fire safety requirements. For example, the fire resistance limit of a low-rise residential house below two floors in the United States is 30 minutes. For fire rating requirements, countries have different national standards according to different actual conditions. Based on China’s actual situation and combined with foreign experience, Xue Fa suggested that because the Chinese people have a strong sense of property, when the fire is burning, people not only have to escape but also have to extinguish fire and save property, which will waste time. Therefore, in the formulation of residential steel structure specifications can not be copied foreign standards, but also with China's national conditions to develop their own product standards.

All in all, if steel construction buildings are to be popularized in China, many problems in technology and production processes will also need to be resolved. In particular, in terms of fire protection and anti-corrosion, the research and development efforts should be further strengthened to solve the problem of fire protection of steel structures as soon as possible.