How to Choose Internally and Externally Coated Steel Pipes

With the laying of various pipelines across the country, the use of pipelines is becoming increasingly widespread. We previously introduced the excellent corrosion resistance of internally and externally coated steel pipes. However, many people find it difficult to choose when purchasing them. The term "coated steel pipe" might be unfamiliar to some, but after my explanation, you'll understand. Coated steel pipes are steel-plastic composite pipes where a layer of plastic anti-corrosion coating is fused onto the inner surface of the steel pipe (base pipe) or onto both the inner and outer surfaces using spraying, rolling, dipping, or suction processes. Today, we'll discuss how to choose internally and externally coated steel pipes.

First, the internally and externally coated steel pipes you choose should meet the certification requirements of the national fire protection testing department. Fire departments play a crucial role in the safety of fire-fighting equipment, and obtaining approval from the fire protection testing department is sufficient proof of the product's quality and reliability.

Second, you can visit the factory in person when purchasing internally and externally coated steel pipes to see the manufacturer's production capacity and the products just coming off the production line. By observing the manufacturer's production process, one can gain a comprehensive understanding of their production capacity and quality.

Thirdly, visiting application examples of the manufacturer's internally and externally coated steel pipes, which are used in large-scale projects, also reflects the superior quality of the pipes.

Currently, over 80% of firefighting pipes worldwide use internally and externally coated steel pipes. This completely solves the problems of corrosion from extinguishing agents, as well as corrosion resistance and flame resistance in both water-filled and waterless conditions, effectively extending the service life of fire-fighting water supply and automatic fire sprinkler systems.

Advantages of Internally and Externally Coated Steel Pipes:

1) Internally and externally coated steel pipes possess excellent properties, adapting to humid environments and withstanding high temperatures, even in extreme temperatures.

2) Internally and externally coated steel pipes have excellent anti-interference capabilities; when used as cable conduits, they can effectively shield against external signal interference.

3) Because of the plastic anti-corrosion layer fused to the surface, internally and externally coated steel pipes have excellent insulation properties, preventing leakage when used as protective conduits for electrical wires.

4) Internally and externally coated steel pipes can withstand pressures up to 6 MPa, which is considered excellent pressure resistance.

5) The plastic coating on the internally and externally coated steel pipe is burr-free, and the pipe wall is smooth, eliminating concerns about running electrical wires or cables during construction.

Where can internally and externally coated steel pipes be used?

Firstly, because of their corrosion resistance, they are widely used in various types of circulating water systems, fire-fighting water supply systems, and water supply and drainage systems in buildings, demonstrating excellent performance. Secondly, they are suitable for ventilation pipes, water supply, and drainage pipes in mines and shafts. Due to their excellent resistance to acid, alkali, and salt corrosion, they are also suitable for transporting various chemical fluids.

As a new type of corrosion-resistant steel pipe, internally and externally coated steel pipes not only possess the advantages of high strength, easy connection, and resistance to water flow impact found in steel pipes, but also overcome the disadvantages of steel pipes, such as susceptibility to corrosion, pollution, and scaling when exposed to water, and the low strength and poor fire resistance of plastic pipes. Their lifespan can reach 50 years.

Before installation, flanges are welded to both ends of the internally and externally coated steel pipe. The flanges must be securely welded. Then, polyethylene coating is applied. During installation, a sealing gasket is placed between the two flanges of the internally and externally coated steel pipe, and then tightened with bolts.

To ensure that internally and externally coated steel pipes do not experience axial movement under the pressure of the transported medium, they need to be fixed in place using supports, brackets, hangers, or similar structures. During fixing, the potential for swaying and bending under pressure must be considered to prevent displacement. For vertically installed internally and externally coated steel pipes, the distance between two fixing points should not exceed 2 meters. For horizontally installed internally and externally coated steel pipes, the distance between the two fixing points needs to be adjusted according to the outer diameter of the pipe in the project.

When fixing with cement or brick supports, the pipe can be embedded in the supports. If using brackets, hangers, or other similar structures, U-shaped or other types of pipe clamps need to be installed on the pipe or fittings. Note that to prevent the pipe clamps from slipping, a rubber pad should be placed between the surface of the internally and externally coated steel pipe and the pipe clamp, and the pipe clamp should be tightened with screws. Then, the pipe clamp should be securely connected to the supports, brackets, or other similar structures using bolts.

Installation can be done according to the user's drawings. If drawings cannot be provided, a specialist needs to go to the site to take measurements and design and manufacture special pipe fittings for connection with mining pipes or for connection with seamless steel pipes using quick-release clamps. During installation, the warning line on the pipe must be kept facing outwards, forming a straight line.