Overview
EN ISO 6504-3:2019 - "Paints and varnishes - Determination of hiding power - Part 3: Determination of hiding power of paints for masonry, concrete and interior use" - specifies standardized laboratory methods to measure the opacity (hiding power) of white and light-coloured paints intended for masonry, concrete and interior applications. The standard covers measurement of tristimulus values (Y and Y10 > 25) and the subsequent calculation of hiding power from coatings applied to either a black-and-white chart or a colourless transparent foil.
Key topics and requirements
- Scope: Applies to white/light paints for masonry, concrete and interior use; focused on paints whose tristimulus values Y and Y10 exceed 25.
- Measurement methods:
- Method A (foil): Apply coating to transparent foil; measure over black and white panels.
- Method B (charts): Direct application to black and white charts.
- Method C (charts, waterborne): New method introduced for waterborne systems (suitable for interior coatings).
- Tristimulus measurements: Y and Y10 values on black and white backgrounds are used to calculate hiding power.
- Spreading rate: Standard specifies a simple method for calculating spreading rate for paints with low-volatility components (e.g., interior wall coatings). Spreading rate may alternatively be determined using ISO 3233-3 or by methods referenced in EN 13300.
- Principle and calculation: Hiding power is evaluated by interpolation because hiding power is approximately linear with the reciprocal of spreading rate within a typical application range.
- Standard content: Defines apparatus, sampling, procedure, calculation, precision, test report requirements and an informative interlaboratory annex.
Practical applications
- Quality control and batch testing in paint manufacturing (opacity verification for interior masonry and concrete coatings).
- Product development and formulation optimization (assessing pigment/binder efficiency and film thickness effects).
- Specification and compliance testing for construction and building materials standards.
- Laboratory accreditation, interlaboratory comparison, and technical dossiers required by regulators or clients.
- Useful to architects, specifiers and contractors who need objective data on coverage rates and expected film thickness for cost and performance planning.
Who should use this standard
- Paint and coating manufacturers, R&D and QC labs
- Test laboratories and certification bodies
- Construction product specifiers and procurement teams
- Regulatory authorities and standards committees
Related standards
- ISO 6504 series (other parts addressing hiding power)
- ISO 3233-3 (density and spreading rate calculation reference)
- EN 13300 (coatings for walls and ceilings - spreading rate guidance)
- ISO 2811 (density of coating materials - referenced for some calculations)
Keywords: EN ISO 6504-3:2019, hiding power, paints for masonry, concrete, interior use, tristimulus Y, spreading rate, opacity testing, Method A B C.
