Overview - EN ISO 536:2020 (ISO 536:2019)
EN ISO 536:2020 (identical to ISO 536:2019) specifies a standardized laboratory method for the determination of grammage (mass per unit area) of paper and board. It defines the principle, required apparatus, sampling and conditioning procedures, the test method, calculation of results and reporting requirements. The standard is used across the paper and board value chain to ensure consistent, reproducible measurement of sheet mass (expressed in g/m²).
Key topics and technical requirements
- Scope and principle
- Grammage is determined by measuring the mass and area of test pieces and calculating mass per unit area.
- Apparatus
- Cutting device capable of producing test pieces within ±1.0% of nominal area (if not achievable each piece’s dimensions must be measured).
- Balance with accuracy to ±0.5% of the measured mass and sensitivity to detect a ±0.2% change.
- Optional special sheet‑weighing balances that give direct grammage readings (with specified calibrated area limits).
- Sampling and conditioning
- Sampling in accordance with ISO 186; specimens conditioned per ISO 187 for “conditioned” and “oven‑dry” grammage determinations.
- “As‑taken” grammage procedures limit ambient moisture effects.
- Test piece size and quantity
- Preferred test piece area: 50 000 mm² to 100 000 mm² (typical 200 mm × 250 mm); minimum permitted area 10 000 mm² if sample is limited (must be reported as deviation).
- Recommended: at least five specimens and sufficient area for ≥20 test pieces (same number from each specimen).
- Calculation and reporting
- Grammage calculated from measured mass and area (standard formulas are provided) and results expressed to three significant figures.
- Report mean and standard deviation and include specified metadata (conditioning, test piece area, number of replicates, any deviations).
- Annexes
- Procedures for oven‑dry and as‑taken grammage and precision data (informative).
Applications and who uses it
- Quality control labs in paper mills and converters for routine grammage verification.
- Incoming inspection for paper merchants and printing/packaging companies to confirm material specifications.
- R&D and material specification development where accurate mass/area data are required.
- Certification bodies and testing services performing standardized test reports used in contracts and compliance checks.
Related standards
- ISO 186 - Sampling to determine average quality
- ISO 187 - Standard atmosphere for conditioning and testing
- ISO 287 - Determination of moisture content (oven‑drying)
Keywords: EN ISO 536:2020, ISO 536:2019, grammage, paper and board, determination of grammage, paper testing, conditioning, sampling, sheet mass, g/m2.
