BIS Engineering Library
Galvanized coating-life estimator.
Enter the project PIN code, then choose the actual atmospheric exposure. The estimate uses ISO 9223 first-year zinc corrosion-rate ranges; it is a screening tool, not a durability guarantee.
Indicative time to first maintenance—
ISO zinc corrosion range—
How to use it
Location helps.
Exposure decides.
A PIN code records project location, but a warehouse interior, sheltered structure and exposed coastal installation in the same area can have different corrosivity. Choose the exposure that matches the actual installation and project specification.
| Category | Typical description | Zinc first-year corrosion rate |
|---|---|---|
| C1 | Very low | ≤ 0.1 µm/year |
| C2 | Low | >0.1–0.7 µm/year |
| C3 | Medium | >0.7–2.1 µm/year |
| C4 | High | >2.1–4.2 µm/year |
| C5 | Very high | >4.2–8.4 µm/year |
| CX | Extreme | >8.4–25 µm/year |
Important: ISO 9223 rates are based on first-year exposure and should not be linearly extrapolated as a design guarantee. Long-term durability, local chloride/pollution, sheltering and project coating specification still need engineering review.