This Standard specifies general rating principles of degradation of coats, rating schemes of single index of degradation as well as the comprehensive rating scheme of degradation of decorative coats and protective coats
This Standard is applicable to rating of the coats degradation performance (natural degradation and artificial accelerated degradation).
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this Standard. For dated references, subsequent amendments (excluding amending error in the text) to, or revisions of, any of these publications are not applicable to this Standard. However, the parties who have entered into agreement according to this Standard are encouraged to research whether the latest editions of these references may be applied or not. For undated references, the latest editions of the normative document are applicable to this Standard.
GB 250 Gray Scale for Assessing Change in Color (GB 250-1995, ISO 105/A02: 1993, IDT)
GB/T 9754 Paints and Varnishes-Determination of Specular Gloss of Non-metallic Paint Films at 20°, 60°and 85° (GB/T 9754-2007, ISO 2813: 1994, IDT)
GB/T 9761 Paints and Varnishes-Visual Comparison of the Color of Paints (GB/T 9761-2008, ISO 3668: 1998, IDT)
GB/T 11186.2 Methods for Measuring the Color of Paint Films; Part 2: Color Measurement (GB/T 11186.2-1989, eqv ISO 7724-2: 1984)
GB/T 11186.3 Methods for Measuring the Color of Paint Films; Part 3: Calculation of Color Differences (GB/ 11186.3-1989, eqv ISO 7724-3: 1984)
ISO 4628-6 Paints and Varnishes -- Evaluation of Degradation of Coatings -- Designation of Quantity and Size of Defects, and of Intensity of Uniform Changes in Appearance -- Part 6: Assessment of Degree of Chalking by Tape Method
ISO 4628-7 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
3 General Principles and Rating Methods
3.1 Rating
In this Standard, figures from 0 to 5 are used to evaluate the damage level and amount: "0" represents no damage and "5" represents severe damage. The determination of the four levels of 1, 2, 3 and 4 shall ensure optimal partition of the entire rating range; if necessary, the intermediate half-level may be adopted for more detailed record of observed damage phenomena.
3.2 Rating of damage level, amount and size
3.2.1 The change degree of damage is used to evaluate the visible uniform damage on coats surface; see Table 1.
3.2.2 The damage amount is used to evaluating the non-continuous or local irregular damage of coats; see Table 2.
3.2.3 Where the damage type has a quantity meaning of size, the rating of damage size shall be added; see Table 3.
