ISO 3233-3:2015

Overview

ISO 3233-3:2015 - Paints and varnishes: Determination of the percentage volume of non-volatile matter - Part 3 - specifies a practical calculation method to obtain the non-volatile matter by volume (NVV) of a coating material from three measured inputs: the non-volatile-matter content by mass (NV) (determined per ISO 3251), the density of the coating material, and the density of the solvent(s) in the coating. The standard also shows how to use the NVV and dry-film density to calculate the theoretical spreading rate. This part is not applicable to coatings that exceed the critical pigment volume concentration (CPVC).

Key topics and technical requirements

• Inputs required
  • NV (non-volatile-matter content by mass) measured in accordance with ISO 3251.
  • Density of the coating material and solvent(s) measured to 0.001 g/cm3 using methods in ISO 2811 (pyknometer, plummet, oscillation, or pressure cup).
  • Dry film thickness measured per ISO 2808 when calculating spreading rate.
• Calculation approach
  • Compute a theoretical dry film density from NV, coating density and solvent density (use the main solvent or the solvent in highest proportion when solvent mix is complex).
  • Calculate non-volatile matter by volume (NVV) from the theoretical dry film density and coating density.
  • Derive the theoretical spreading rate from NVV, dry film thickness and density.
• Special provisions
  • For waterborne systems, use the density of the total solvent composition (including water). If solvent density is unknown, recommended default densities are provided (e.g., ~0.80 g/cm3 for aliphatic hydrocarbons, ~0.87 g/cm3 for aromatics, 1.00 g/cm3 for water-rich systems).
  • The method is unsuitable above CPVC because film porosity invalidates the theoretical volume assumption.
• Precision and reporting
  • The standard includes information on precision (repeatability and reproducibility limits) and required test-report content, plus informative annexes with derivations and calculation examples.

Practical applications and users

• Who uses ISO 3233-3:2015:
  • Paint and varnish formulators and R&D teams
  • Quality control and testing laboratories
  • Coating manufacturers and technical services
  • Automotive and commercial vehicle coating specifiers
• Typical uses:
  • Quick estimation of NVV for production QC and batch records
  • Calculation of theoretical spreading rate for specification and process planning
  • Comparing theoretical film volumes across formulations during development
• Notes:
  • Results differ from some ASTM methods (e.g., ASTM D2697/D5201) - be aware when comparing across standards.

Related standards

• ISO 3251 - determination of non-volatile-matter content
• ISO 2811 series - determination of density
• ISO 2808 - determination of film thickness
• ISO 3233-1 and ISO 3233-2 - alternative methods for NVV determination

This concise method is valued for speed and practical applicability in industry settings where quick NVV estimates and theoretical spreading rates are needed.