Overview - EN ISO 2811-3:2023 (Oscillation method for density)
EN ISO 2811-3:2023 specifies an oscillation method for determining the density of paints, varnishes and related products. The method uses a vibrating U‑tube (glass or stainless steel) whose resonance frequency changes with the mass of the filled tube. It is suitable for all material forms, including paste-like coatings, and - when a pressure‑resistant apparatus is used - can also be applied to aerosols. The standard replaces EN ISO 2811-3:2011 and aligns with ISO 2811-3:2023.
Key topics and technical requirements
- Principle: Density is derived from the resonance period (T) of a clamped, oscillating U‑tube; some instruments display density directly.
- Apparatus: U‑tube oscillator, thermometer (±0.2 °C), temperature-controlled chamber, disposable syringe. Instruments may show period or compute density internally.
- Temperature control: Tests are carried out at (23.0 ± 0.5) °C (other agreed temperatures possible). Sample, tube and oscillator must be conditioned and maintained within ±0.5 °C during measurement.
- Sampling and sample prep: Follow ISO 15528 (sampling) and ISO 1513 (examination/preparation) for representative and prepared test samples.
- De‑aeration: To ensure reproducible results, samples shall be de‑aerated before measurement (e.g. short high‑shear mixing for waterborne matrices was found suitable).
- Measurement practice:
- If reading period T: take ≥3 readings of T and ≥2 temperatures; T values should agree within 0.0001 ms.
- If reading density directly: take ≥3 density and ≥2 temperature readings; density values should agree within 0.0002 g·cm‑3.
- Avoid air bubbles and ensure the display indicates air density before and after tests.
- Calculation and calibration: When T is measured, density is calculated using apparatus constants A and B (Annex A describes calibration). Annex B provides density values for damp air and air‑free water; Annex C covers temperature corrections.
- Precision and reporting: The standard includes repeatability and reproducibility considerations and a defined test report format.
- Quality control laboratories in coatings and varnish manufacturing
- R&D teams validating formulation density, solids content and filling properties
- Contract testing and certification bodies
- Aerosol product testing when using pressure‑resistant oscillation apparatus
- Production engineers controlling process dosing and mixing where accurate density data are required
Related standards and keywords
- Normative references: ISO 1513, ISO 15528; part of the ISO 2811 series for paints and varnishes.
- SEO keywords: EN ISO 2811-3:2023, density determination, oscillation method, paints and varnishes, U‑tube oscillator, density of coatings, de‑aeration, temperature control, apparatus calibration.
This standard provides a robust, reproducible method for measuring coating density that supports QC, formulation development and regulatory testing across the coatings industry.