Overview
ISO 23996:2007 - "Resilient floor coverings - Determination of density" defines two standardized laboratory methods for measuring the density of homogeneous resilient floor coverings and the solid layers of other resilient floor coverings. The document specifies sampling, conditioning (23 ± 2 °C; 50 ± 5 % RH), test-piece selection, apparatus, calculation methods and reporting requirements to ensure reproducible, comparable density results for tiles and sheet materials.
Key topics and technical requirements
- Scope & sampling
- Apply to homogeneous resilient coverings and solid layers.
- Take three tiles or a sheet sample of at least 1 000 mm × 1 000 mm.
- Atmosphere for conditioning
- Condition samples at (23 ± 2) °C and (50 ± 5) % RH for a minimum of 24 hours.
- Method A - Immersion (buoyancy)
- Principle: weigh a test specimen in air and while immersed in distilled water (containing ≤ 0.1 % wetting agent) and calculate density from the mass difference.
- Apparatus: balance (sensitivity 1 mg), thin wire (≤ 0.125 mm diameter), beaker (200 ml), pad straddle.
- Specimen size: minimum 30 mm × 30 mm or diameter 36 mm; three specimens from equal distances.
- Calculation: ρ = (m1 × ρ_H2O) / (m1 − m2), where m1 = mass in air, m2 = mass when immersed, ρ_H2O = water density at test temperature. Report mean for three specimens, rounded to 1 kg/m³.
- Method B - Dimensional (mass/volume)
- Principle: determine mass and geometric volume (length × width × thickness) and compute density as mass/volume.
- Not suitable when surface or back has a texture.
- Apparatus: measuring devices per ISO 24342 (dimensions) and ISO 24346 (thickness), balance (1 mg sensitivity).
- Specimen size: at least 100 mm × 100 mm; use three specimens or three tiles.
- Calculation: ρ = 10 × M / V (M in grams, V in mm³). Report mean, rounded to 0.1 kg/m³.
- Reporting
- Tests must state the method used (A or B), dates, product ID (type, colour, manufacturer reference), previous history, any deviations, and mean density.
- Precision
- A round-robin test is indicated to determine method precision.
Applications and who uses this standard
- Flooring manufacturers: quality control, product specification and consistency checks.
- Independent test laboratories: standardized testing for certifications and client reporting.
- Specifiers, architects, procurement teams: verify declared densities for performance expectations (durability, wear, underfoot feel).
- R&D and material suppliers: material development and batch comparison.
- Compliance and certification bodies: ensure uniform test methods when assessing resilient flooring.
Related standards
- ISO 24342 - Determination of side length, edge straightness and squareness of tiles
- ISO 24346 - Determination of overall thickness
- ISO 1183 (all parts) - Density methods for plastics
- EN 436 - Resilient floor coverings - Determination of density
Keywords: ISO 23996:2007, resilient floor coverings, density determination, immersion method, dimensional method, flooring quality control, flooring test methods.