How to repair failed fire and corrosion protective coatings on steel structure surfaces?

Shovel it off and spray new paint – fixing it is pointless

This situation is common in coastal petrochemical plants, as the high salt content and humid environment accelerate the aging of coatings. The repair process involves several steps: 1. **Thorough cleaning first**: Use sandblasting or mechanical grinding to remove all the damaged coating and rust, exposing the metal substrate; special attention should be paid to cleaning the edges and gaps. 2. **Select coatings appropriately**: - **Corrosion-resistant primer**: In coastal areas, epoxy zinc-rich primers or inorganic zinc-rich paints are recommended due to their excellent rust prevention properties. - **Intermediate coat**: An epoxy limonite intermediate coat is used to increase the thickness of the coating and enhance its sealing properties. - **Fireproof coating**: Choose a thick fireproof coating, and pay attention to its compatibility with the anti-corrosion coating. - **Topcoat**: Use a weather-resistant polyurethane or fluorocarbon topcoat that is resistant to ultraviolet rays and salt spray. 3. **Strict construction requirements**: Construction can only proceed when the environmental humidity is below 85% and the temperature of the steel plates is at least 3°C above the dew point. - The thickness of each coat should be controlled according to the manufacturer’s specifications, and the next coat should be applied only after the previous one has fully dried. - If necessary, a waterproof topcoat should be applied after the application of the fireproof coating. 4. **Regular inspection and maintenance**: Check the condition of the coating every six months going forward, and repair any minor damage promptly to avoid extensive rework. The key is to clean the surface properly, choose a suitable coating system, and apply it correctly, so that it can last for a long time. .