Corrosivity, surface prep grades, system film thickness — the basis for selection and application.
| Grade | Typical Environment | Low Carbon Steel Annual Corrosion | Zinc Annual Corrosion | Design Life |
|---|---|---|---|---|
| C1 Very Low | Heated Clean Interior | ≤1.3 μm | ≤0.1 μm | Ordinary decorative coating sufficient |
| C2 Low | Rural atmosphere | 1.3-25 μm | 0.1-0.7 μm | Alkyd single-coat |
| C3 medium | City / industrial atmosphere, medium SO₂ | 25-50 μm | 0.7-2.1 μm | Epoxy primer + polyurethane topcoat, total film 160μm |
| C4 High | Industrial area / coastal | 50-80 μm | 2.1-4.2 μm | Zinc-rich primer + Epoxy MIO + Polyurethane, 200μm |
| C5-I Very High (Industrial) | High-humidity industrial area | 80-200 μm | 4.2-8.4 μm | Zinc-rich + MIO + Polyurethane, 240μm |
| C5-M Very High (Marine) | Coastal / offshore | 80-200 μm | 4.2-8.4 μm | Zinc-rich + MIO + Polyurethane, 260μm |
| CX Extreme | Extreme industrial / marine environments, splash zones, desalination plants | >200 μm | >8.4 μm | Zinc-rich + Glass Flake + Fluoropolymer, 320μm+ |
| Grade | Environment | Recommended System | Dry Film Thickness |
|---|---|---|---|
| Im1 | Fresh water immersion | Epoxy primer + epoxy topcoat | 2×160μm |
| Im2 | Seawater / saltwater immersion | Epoxy coal tar / glass flake | 2×300μm |
| Im3 | Buried soil | Epoxy coal tar / PE Powder | ≥400μm |
| standard | Grade | Treatment method | Appearance | Application |
|---|---|---|---|---|
| ISO St2 | Hand/power tool cleaning | Wire brush/grinder | No visible grease, mill scale | Light maintenance |
| ISO St3 | Power tool cleaning to near white | Wire brush / grinder grinding | Metallic luster | Local repair |
| ISO Sa1 | Light blast cleaning | Blast | No grease, loose mill scale removed | Old coating maintenance |
| ISO Sa2 | Commercial blast | Blast | 95% surface free of visible contamination | General anti-corrosion |
| ISO Sa 2.5 | Near white grade blasting (Near White) | Blast | 99% no visible impurities, uniform metallic gloss | Anti-corrosionstandard |
| ISO Sa3 | White grade blasting (White Metal) | Blast | 100% uniform metallic luster | Marine/extreme corrosion |
| SSPC | ISO Equivalent | Name | Description |
|---|---|---|---|
| SP-1 | — | Solvent cleaning | Degreasing, essential before all coating |
| SP-2 | St2 | HandTool cleaning | Hand scrape/brush |
| SP-3 | St3 | PowerTool cleaning | Power grinder/wire brush |
| SP-5 | Sa3 | White metal blast | White Metal Blast |
| SP-6 | Sa2 | Commercial blast | Commercial Blast |
| SP-7 | Sa1 | Brush-off blast | Brush-off Blast |
| SP-10 | Sa 2.5 | Near white metal blast | NACE No.2 / Near-White |
| SP-11 | — | Power tool to near white | Profiles ≥25μm |
| Grade | primer | medium coating | topcoat | Total DFT | Durability |
|---|---|---|---|---|---|
| C3 | Epoxy zinc-rich 60μm | Epoxy MIO 80μm | Polyurethane 60μm | 200μm | High(15 years) |
| C4 | Epoxy zinc-rich 70μm | Epoxy MIO 130μm | Polyurethane 60μm | 260μm | High(15 years) |
| C5-I/M | Epoxy zinc-rich 80μm | Epoxy MIO 160μm | Polyurethane/Fluoropolymer 60μm | 300μm | Very high (20 years) |
| CX | Epoxy zinc-rich 80μm | Epoxy glass flake 200μm | Fluoropolymer 60μm | 340μm | Extreme (25+ years) |
| Im2 seawater | Epoxy coal tar 300μm | — | Epoxy coal tar 300μm | 600μm | 10-15 years |
| Im3 buried underground | PE Powder 300μm | — | — | 300μm | 20 years |
Email us your environment conditions (city / coastal / industrial / buried / immersion), we directly output BACOAT system.
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