Technical analysis of DN125 national standard fire-fighting plastic-coated steel pipe

First, the core performance advantages of fire-fighting plastic-coated steel pipe

1. Corrosion resistance of fire-fighting plastic-coated steel pipe: adopts inner and outer double-layer coating process, the outer thermosetting powder coating has anti-impact and anti-corrosion properties, and the inner food-grade thermoplastic coating forms a protective barrier, effectively resisting the erosion of corrosive media such as acids, alkalis, and salts, and extending the service life of the pipeline by 30-50 years.

2. Temperature resistance of fire-fighting plastic-coated steel pipe: the working temperature range is -30℃ to 200℃, high temperature does not soften and deform, and low temperature does not crack. Maintain structural integrity in high temperature environment of fire to ensure the continuity of fire water supply.

3. Mechanical properties of fire-fighting plastic-coated steel pipe: with high-quality steel pipe as the base material, compressive strength ≥5.0MPa, bending resistance ≤0.2%. The coating adhesion reaches 30N/cm (polyethylene) or level 3 (epoxy resin), verified by the 1.5D bending test and DN200 flattening test.

4. Fluid characteristics of fire-fighting plastic-coated steel pipes: The inner wall roughness is ≤0.007mm, which increases the flow efficiency by 40% compared with traditional steel pipes. The food-grade coating prevents the growth of microorganisms and avoids the risk of blockage in the sprinkler system.

Second, production process control of fire-fighting plastic-coated steel pipes

1. Base material selection of fire-fighting plastic-coated steel pipes: straight seam welded pipes (DN15-600), spiral welded pipes (DN200-3000), and seamless steel pipes (high-pressure scenarios), and the wall thickness error is controlled within ±10%.

2. Surface treatment of fire-fighting plastic-coated steel pipes: two-stage sandblasting and rust removal reaches Sa2.5 level, and the anchor pattern depth is 40-100μm. Pickling and phosphating form a 3-5μm conversion film to improve the bonding strength of the coating.

3. Coating process of fire-fighting plastic-coated steel pipes: epoxy resin coating (environment below 80℃) thickness ≥150μm, polyethylene coating (general environment) thickness ≥300μm. Adopt electrostatic spraying + high temperature curing process, pass 3.0kV/mm electric spark detection.

Third, application scenarios of fire-fighting plastic-coated steel pipes

1. Building fire protection system: suitable for super high-rise buildings (Shanghai Center case), commercial complexes (China World Mall case) and residential projects, meet the working pressure requirements of 2.5MPa, and adapt to grooves, flanges and other connection methods.

2. Municipal pipe network: withstand soil stress of 0.8MPa, and its application in coastal cities such as Xiamen has proved its ability to resist Cl- corrosion. Trenchless technology is used in the renovation project, and construction efficiency is increased by 60%.

3. Industrial fire protection: The petrochemical field has passed the NACE TM0177 standard certification, and the power system meets the GB/T 14823 electrical insulation requirements. The application case of the oil tank area shows that the ability to resist hydrocarbon fires has increased by 50%.

Fourth, comparative advantage analysis of fire-fighting plastic-coated steel pipes

1. Fire-fighting plastic-coated steel pipes vs. ordinary steel pipes

The anti-corrosion life is extended by 5 times, and the maintenance cost is reduced by 80%. The water flow efficiency is increased by 30%, and the installation cycle is shortened by 40%.

2. Fire-fighting plastic-coated steel pipe vs. galvanized steel pipe

The anti-scaling performance is improved by 90%, and the microbial control meets the GB/T 17219 standard. The life cycle cost is reduced by 65%, and no regular coating maintenance is required.

Fifth, development trend

The research and development of new nano-composite coatings will increase the upper-temperature limit to 300℃, and intelligent monitoring coating technology will achieve corrosion early warning. The green production process reduces VOC emissions by 95%, which meets the GB 30981 environmental protection standard. This product has passed the GB/T 5135.20 certification and achieved zero failure records in 50 key fire protection projects, providing reliable protection for modern fire protection systems. It is recommended to give priority to EP-grade epoxy coatings when designing and selecting, and the construction process strictly follows the CECS 125 specification.