Overview
EN ISO 5350-2:2006 (ISO 5350-2:2006) - published by CEN/ISO - specifies a visual method for the estimation of dirt and shives in mill sheeted pulp by transmitted light. The procedure quantifies visible contraries (non‑fibrous dirt and shives) on sheeted pulp and reports the total contrary area as mm² per kg of oven‑dry pulp. The standard applies to most mill sheeted pulps (typical maximum grammage ~800–1 000 g/m²) but excludes unbleached kraft pulps, very opaque sheets and recycled pulps.
Key Topics and Requirements
- Principle: Inspect wet or sufficiently transparent test pieces in transmitted light and estimate the area of visible contraries using a comparison chart (Annex A).
- Sampling & test piece selection: Follow ISO 7213 for sampling; inspect representative pieces totalling at least 300 g dry mass (≥0.5 m² area). If preliminary counts exceed 300 contraries/kg, the inspected mass may be reduced to 100 g (must be reported).
- Dry matter: Determine dry matter content per ISO 638 before calculating results.
- Wetting: Test pieces are normally wetted to improve transparency; omission must be recorded. Verify visibility by marking a small speck and checking from the reverse side.
- Apparatus: Use a viewing table with transmitted artificial daylight. Luminance shall be 2 500–3 000 cd/m² at the table surface. Use the normative comparison chart (do not use photocopies).
- Minimum detectability & size classes: Only contraries ≥0.04 mm² are counted. Recommended size classes (area ranges in mm²):
- Class 1: above 5
- Class 2: 1.00–4.99 (log mean 2.482)
- Class 3: 0.40–0.99 (log mean 0.651)
- Class 4: 0.15–0.39 (log mean 0.251)
- Class 5: 0.04–0.14 (log mean 0.080)
- Results: Sum estimated areas and report as mm² per kg oven‑dry pulp; class‑wise reporting is optional. Annex B provides an informative instrumental procedure for automated inspection.
Applications and Users
EN ISO 5350-2:2006 is used for:
- Pulp mill quality control - routine inspection of mill sheeted pulp.
- Incoming inspection and trade acceptance - buyer/seller specifications and lot acceptance.
- Laboratory testing - pulp testing labs and third‑party inspectors.
- Process troubleshooting - identifying production issues causing contamination (dirt/shives).
Primary users: pulp manufacturers, paper mills, QC laboratories, procurement teams, and standards auditors.
Related Standards
Keywords: EN ISO 5350-2:2006, ISO 5350-2, pulps, dirt and shives estimation, transmitted light inspection, mill sheeted pulp, pulp testing, viewing table, comparison chart.
