General
Coatings Radar App has an interactive Re Scale for various industries, including offshore, petrochemical, wind and marine. The Re Scale for ballast tanks includes aged tank coatings with rust staining.
To assess or determine the level of rusting on a coated surface, various international documents and standards are utilised.
One widely used document is the "European Scale of Degree of Rusting for Anticorrosive Paints" developed in the 1960s. This document contains black and white photographs displaying different degrees of rusting on a steel substrate coated with an oil-based air-drying anticorrosive paint. The booklet consists of 10 photographs ranging from Grade Re 0 (no visible corrosion) to Grade Re 9 (95% visible corrosion).
Additionally, standards set by organisations such as SSPC, ASTM, and ISO are used to evaluate the extent of rusting on painted steel surfaces. The correlation between these standards and the degree of rusting is detailed in the following table.
| SSPC-VIS / ASTM D610 | ISO 4628-3* | European Rust Grade | ||
|---|---|---|---|---|
| Area Rusted | Rust Grade | Area Rusted % | Rust Grade | |
| < 0.01 | 10 | 0 | Ri0 | Re0 |
| 0.03 to 0.1 | 8 | 0.05 | Ri1 | Re1 |
| 0.3 to 1 | 6 | 0.5 | Ri2 | Re2 |
| 0.3 to 1 | 6 | 1 | Ri3 | Re3 |
| 3 to 10 | 4 | 8 | Ri4 | Re5 |
| 33 to 55 | 1 | 40/50 | Ri5 | Re7 |
* ISO 4628-3 (This standard uses the photographs from European Scale of Degree of Rusting for Anticorrosive Paints)