GB/T 30789.7-2015
Paints and varnishes.Evaluation of degradation of coatings.Designation of quantity and size of defects, and of intensity of uniform changes in appearance.Part 7:Assessment of degree of chalking by velvet method (English Version)

Standard No.: GB/T 30789.7-2015
Language: Chinese, Available in English version
Release Date: 2015
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB/T 30789.7-2015

Scope: This part of GB/T 30789 specifies a method for assessing chalking grades, especially suitable for white or other colored paint coatings and multi-coat systems on rough surfaces (for example, roughness greater than that specified in ISO 8503-1) The 4th paragraph in degree comparison sample block G) pulverization grade evaluation. The method specified in this section can also be used for coatings on smooth surfaces and the evaluation of the chalking level of multi-coating systems, but the method specified in ISO 4628-6 is more suitable. This test method is applicable to coatings and multi-coating systems on mineral substrates, such as: fiber cement boards, bricks, concrete and subfloor mortars, and the test is not affected by the surface structure. This method is very effective for experienced operators and can be used for laboratory and field evaluation. ISO 4628-1 defines the identification of the number and size of coating aging defects and the degree of uniform change in appearance, and outlines the general principles of the evaluation system. This rating system is especially suitable for aging-induced defects and general types of damage, such as color changes, yellowing, etc.

GB/T 30789.7-2015 Referenced Document

GB/T 13288.1 Preparation of steel substrates before application of paints and related products.Surface roughness characteristics of blast-cleaned substrates.Part 1:Specification and definitions for ISO surface profile comparators for the assessment of abrasive blast-c
ISO 4628-1 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*， 2016-01-01 Update
ISO 4628-6:1990 Paints and varnishes; evaluation of degradation of paint coatings; designation of intensity, quantity and size of common types of defect; part 6: rating of degree of chalking by tape method

2015 GB/T 30789.7-2015 Paints and varnishes.Evaluation of degradation of coatings.Designation of quantity and size of defects, and of intensity of uniform changes in appearance.Part 7:Assessment of degree of chalking by velvet method