ISO 5350-1:2006

Overview

ISO 5350-1:2006 - Pulps - Estimation of dirt and shives - Part 1: Inspection of laboratory sheets by transmitted light defines a standardized visual method to estimate visible dirt and shives in laboratory sheets formed from pulp. The method is intended mainly for pulps not manufactured in sheet form but can be applied to opaque mill sheeted pulps. It is not intended for recycled pulp. Results are reported as total area of contraries expressed in mm² per kg of oven-dry pulp.

Key topics and technical requirements

• Principle: Visual inspection of laboratory sheets under transmitted light; areas of contrasting particles (contraries) are estimated and summed.
• Scope limits: Not for recycled pulp; some mechanical pulps may be impractical for this method.
• Sampling & sample size: Test portions must be representative (ISO 7213). At least 100 g oven-dry pulp is required for inspection (180 g recommended to allow preliminary testing).
• Disintegration & sheet preparation: Follow ISO 5263‑1/2/3 for disintegration and ISO 5269‑1/2 for laboratory sheet forming; ensure clean apparatus and filtered water.
• Viewing conditions: Use a viewing table with transmitted artificial daylight; luminance at the table surface should be 2,500–3,000 cd/m². Avoid external daylight.
• Comparison chart: Use the transparent comparison chart in Annex A for area estimation - do not use photocopies.
• Size thresholds & classification: Only contraries with area ≥ 0.04 mm² are counted. The standard defines size classes (with logarithmic mean areas) for reporting and calculation.
• Calculation & reporting: Total area (or by class/dirt vs shive) is calculated in mm²/kg using class mean areas; report to nearest integer (results <5 mm²/kg to one decimal place).
• Instrumental options: Annex B is informative - visual inspection is the normative basis; instrumental procedures are referenced but not normative in this part.

Applications and users

ISO 5350-1:2006 is used by:

• Pulp and paper mill quality control (QC) labs to quantify dirt and shives during process control and acceptance testing.
• Independent testing laboratories and contract analytical services performing pulp qualification.
• R&D and pilot plants evaluating pulping, bleaching, cleaning, and refining processes.
• Procurement/QA teams specifying acceptance criteria for incoming pulp lots.

Benefits: consistent reporting in mm²/kg, comparability across labs, and guidance for sample preparation and inspection conditions.

Related standards

• ISO 5350-2:2006 - Inspection of mill sheeted pulp by transmitted light
• ISO 5350-3 - Visual inspection by reflected light (EBA method)
• ISO 5350-4 - Instrumental inspection by reflected light (EBA method)
• ISO 5263 series - Laboratory wet disintegration
• ISO 5269 series - Preparation of laboratory sheets
• ISO 638 - Determination of dry matter content
• ISO 7213 - Pulps - Sampling for testing

Keywords: ISO 5350-1:2006, pulps, dirt and shives estimation, transmitted light inspection, laboratory sheets, pulp testing, quality control, comparison chart, mm²/kg.