Overview
ISO 186:2002 - Paper and board: Sampling to determine average quality specifies a standard method for obtaining a representative sample from a lot of paper or board (including solid and corrugated fibreboard) to test whether the lot’s average quality meets agreed specifications. The fourth edition (2002) defines how to select units, sheets and specimens, how to prepare test pieces, and what must be recorded in a sampling report. It is intended for acceptance testing and dispute resolution between buyer and seller.
Key points
- Purpose: produce a representative sample from a defined lot for testing average quality, not for assessing within‑lot variability.
- Mandatory limitation: if less than 50% of the lot is available, sampling under this standard is invalid unless both parties agree otherwise.
- Annex A: provides alternative procedures when standard sampling is impossible or impractical (not applicable in disputes).
Key topics and requirements
- Selection of units: number of units to select depends on lot size (e.g., for lots of 6–399 units select n + 20 units at random; for 400+ units select 20 units at random; 1–5 units: sample all).
- Sheets and reels: procedures cover units that can be unwrapped, packaged elements (reams/parcels), and reels/rolls (remove damaged outer layers, take sheets across the width so all sections are represented).
- Specimen dimensions: specimens must be uniform in size. Typical minima: 300 mm (cross direction) × 450 mm (machine direction) or 450 × 450 mm squares when machine direction is unknown; guidance also given for small sheets and manufactured articles.
- Random selection: sheets and specimens must be selected at random so each part of the lot has an equal chance of selection.
- Handling and marking: specimens must be kept flat, protected from contamination, and indelibly marked to ensure traceability.
- Sampling report: must document reference to ISO 186, sampler name, date/place, lot identification, unit counts, sheets/articles selected, identification marks, and any conditions affecting results.
Practical applications
- Incoming quality control and acceptance testing for paper mills, converters, printers and packaging manufacturers.
- Contractual dispute resolution between buyer and seller over paper or board deliveries.
- Customs inspection and sampling where a defined lot must be verified.
- Laboratory testing where traceable, representative samples are required for standardized tests.
Who uses this standard
- Quality managers at paper and packaging manufacturers
- Procurement and QC teams at converters/printers
- Independent testing laboratories and certification bodies
- Customs and inspection authorities involved in trade disputes
Related standards
- ISO 4046 (vocabulary for paper and board) - referenced for terminology
- ISO 2859 series and ISO 3951 - sampling procedures for inspection by attributes/variables (listed in ISO 186 bibliography)
Keywords: ISO 186:2002, paper sampling, sampling to determine average quality, paper and board sampling, representative sample, specimen preparation, sampling report, dispute resolution.
