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October 22, 2025

What Is the Role of Surface Cleaning for Fire-retardant Coatings on Steel Structures (part 1)?

To learn about all aspects related to Movable Partition Wall, you can consult our comprehensive guide on Movable Partition Walls Hub.

Premium movable partition walls adopt high-quality steel as the core structural material, which determines the overall stability, safety and durability of the partition products. All steel components of custom movable partition walls require professional and specialized industrial processing before formal installation and application.

Among all processing procedures, surface cleaning treatment for steel structure fire-retardant coatings is one of the most critical links, running through the entire stage of pre-construction preparation, on-site construction and post-construction inspection. Scientific and standardized fire-resistant coating surface cleaning can fully guarantee the stable fire-proof performance of modern space partition walls, effectively improve coating bonding quality and finishing effect, greatly extend the service life of steel partition structures, and comprehensively escort the construction safety and long-term safe use of various interior partition projects. 

1. Pre-construction Cleaning: Lays the Foundation for Coating Adhesion

Removes Impurities and Enhances Adhesion
How they Work: Impure substances like oil, rust dust, coatings that are old, or even weld spatter can remain in the steel's surface structures. They form physical barriers, preventing any direct interaction between coating and the surface, which results in less adhesion of the coating.
Specific Impacts:
Oil Grease and oil are the two main ingredients that make the coating more distinct from steel, creating the "oil film" that renders the coating more prone to flake.
Rust The layer of iron oxide is porous and loose. It's and is impermeable to coatings, creating a separation between the substrate. Dust particles could be absorbed into the coating, creating tiny gap and decreasing fireproof sealing.

Cleaning Methods
Mechanical Cleaning: Make use of wire brushes, sandpaper or sandblasting equipment for removing the old coatings and rust.
Chemical Cleaning: Apply the solvent (such as Acetone) to clean oil-based stains or an acid-pickling solution to get rid of an incredibly rusty.
The Power Tool Cleaner: Utilize the rotating metal brush or grinder to swiftly remove surface impurities.

Improving Surface Roughness to Optimize Coating Bonding
What it does: The right roughness of the surface improves amount of contact between the surface and the substrate producing a mechanical interlocking as well as improving the adhesion.
Specific Impacts:
Lack of roughness (e.g. or a smooth mirror surface) A coating that is not rough enough vulnerable to slippage, and its fireproofing abilities are not fully utilised.
Overly roughness (e.g. excessive sandblasting) The thickness of the coating could be irregular, which can affect an even fireproofing.
Standard Requirements: In accordance with the "Technical Specifications for the Use of Fire Retardant Coatings on steel Structures," the surface roughness prior to coating must be maintained between 40 and 70mm.

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2. Cleaning During Application: Ensure Coating Uniformity and Integrity

Remove Application Contamination and Prevent Coating Defects
What it does When you apply the coating dirt, fly insects or even paint drips in the surrounding environment could cause contamination to the coating that is not yet cured creating defects, such as pinholes, dust particles, or gaps.
Specific Impacts:
Particles: The impurities that are embedded into the coating could cause weak spots, which makes the coating susceptible to cracking when exposed to very high temperatures.
Pinholes: Small pores created through solvent or air vaporization may reduce efficiency of thermal insulation.
Sags: A buildup of paint results in uneven thickness. This affects the efficacy of the fireproofing.

Cleaning Methods
Instant Cleaning: Clean the dirt from the surface using a clean fabric or air compressed.
For local repairs, sand the damaged region and then apply the paint again.

Control Environmental Conditions to Avoid Secondary Contamination
What it does: Extreme temperatures, extreme humidity or powerful winds may accelerate drying the coating. This leads to dust absorption.
Specific Impacts:
At high temperatures, the paint sets quickly and causes the formation of a crust over the entire surface. The interior is not completely dry.
The high humidity and moisture retention may cause blistering or whitening of the layer. Countermeasures:
Secure the construction zone Dust screens can be installed or temporary enclosures in order to minimize pollution from the outside.
Monitor humidity and temperature: Make use of a humidifier or heating device to ensure that the surrounding environment is in line with the requirements for painting (typically 535°C at a temperature of 35°C with a humidity that is less than percent).

Related Articles: What Is the Role of Surface Cleaning for Fire-retardant Coatings on Steel Structures (part 2)?
What Determines the Frequency and Duration of Cleaning?

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