Assessment of degree of rusting
BS EN ISO 4628-3-2003 pdf free.Paints and varnishes一 Evaluation of degradation of coatings一Designation of quantity and size of defects, and of intensity of uniform changes in appearance一 Part 3: Assessment of degree of rusting.
This part of ISO 4628 describes a method for assessing the degree of rusting of coatings by comparison with pictorial standards.
The pictorial standards provided in this part of ISO 4628 show coated steel surfaces which have deteriorated to different degrees by a combination of rust broken through the coating and visible underrust.
NOTE 1 The pictorial standards have been selected from the “European rust scale” published by the European Confederation of Paint, Printing Ink and Artists’ Colours Manufacturers’ Associations (CEPE). Brussels. The correlation between the ISO scale and the “European rust scal& is given in Annex B, Table B,1.
NOTE 2 The correlation between the ISO scale and the rating system of ASTM 0 610, Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces, is given in Annex B, Table B.2.
NOTE 3 The rust formation on uncoated steel surfaces is designated in accordance with ISO 8501-1, Preparation of steel substrates before application of paints and related products — Visual assessment of surface cleanliness — Part 1:
Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings (rust grades A, B. C and D).
ISO 4628-1 defines the system used for designating the quantity and size of defects and the intensity of changes in appearance of coatings and outlines the general principles of the system. This system is intended to be used, in particular, for defects caused by ageing and weathering, and for uniform changes such as colour changes, for example yellowing.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 4628-1:2003, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 1: General introduction and designation system.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
degree of rusting
rating characterizing the degree of rust formation (rust broken through and visible underrust) on a coating
Assess the degree of rusting Ri on a coating by means of the pictorial standards given in Figures 1 to 5. The approximate areas rusted (rust broken through plus visible underrust) shown on these standards are as indicated in Table 1.
Procedures fo- assessing invisible underrust, if required, shall be agreed between the interested parties.
Where different degrees of rusting occur in different parts of the area being assessed, indicate these degrees of rusting together with the part where each occurs.
Carry out the assessment under good illumination.
If the average size of the rust spots on the test area differs considerably from those shown in the pictorial standards, an indication of their size may be given by reference to Table 2 of ISO 4628-1:2003.
NOTE The pictorial standards are basically intended for assessing the degree of rusting of coated steel. They may be used for designating the degree of corrosion of coated non-ferrous metals if the form of breakdown is comparable with that shown in the standards.
If the assessment is to be done using an optical imaging system, calibrate the system using the images given in Annex A.
5 Expression of results
Express the degree of rusting as the Ri class as shown in Figures 1 to 5.
If applicable, indicate the different degrees of rusting obtained, together with the parts of the test area
If applicable, indicate the degree of rusting Ri together with the numerical rating of the size of the rust spots.
For example, if the rusted area corresponds to Figure3, Ri 3, and the sizes of the individual rust spots are between 0,5 mm and 5 mm, reported the result as:
rusting; degree of rusting Ri3 (S4)
6 Test report
The test report shall contain at least the ollowing information:
a) all details necessary to identify the coating examined;
b) a reference to this part of ISO 4628 (ISO 4628-3:2003);
c) the type of surface examined, its size and, if appropriate, its location;
d) the result of the assessment in accordance with Clause 5;
e) an indication of the ilumination under which the assessment was carried out;
f) any unusual features (anomalies) observed during the assessment;
g) the date of the examination.BS EN ISO 4628-3 pdf free download.Assessment of degree of rusting