EN ISO 638-1:2022

Overview

EN ISO 638-1:2022 - "Paper, board, pulps and cellulosic nanomaterials - Determination of dry matter content by oven-drying method - Part 1: Materials in solid form" - specifies an oven-drying procedure to determine the dry matter content (and by complement, moisture content) of paper, board, pulp and cellulosic nanomaterials in solid form. The method uses an oven temperature of 105 °C ± 2 °C and is intended for materials that do not contain appreciable quantities of non‑water volatiles at that temperature. It is widely used when dry mass is needed to express chemical or physical test results on a dry basis.

Key topics and requirements

• Scope: Applies to solid-form paper, board, pulp and cellulosic nanomaterials (virgin and/or recycled). Not applicable to slush pulp or to determining saleable mass of pulp lots.
• Oven-drying principle: Drying to a constant mass at 105 °C ± 2 °C; calculation of dry matter content as the ratio of oven-dry mass to original mass.
• Total dry matter: Results include dissolved solids present in the sample. If only cellulosic solids are required, dissolved solids must be removed (e.g., washing or dialysis) prior to drying.
• Sampling and preparation: References established sampling standards (ISO 186, ISO 7213, EN 17085) and gives guidance on preparing representative test pieces.
• Precision and reporting: Precision data and guidance are provided (see Clause 10 and informative Annex B). Test report requirements and calculation examples are included.
• Limitations: Do not use where significant volatile non-water components exist at the test temperature.

Practical applications and users

Who uses EN ISO 638-1:2022:

• Quality control laboratories in paper mills and converting plants checking moisture and dry matter.
• Analytical and environmental labs needing dry‑basis results for chemical analyses (e.g., metals or additives).
• R&D teams working with cellulosic nanomaterials (CNMs) and pulp formulations.
• Recycling operations assessing dry matter of paper and board for recycling streams.

Why it’s used:

• To convert measured concentrations to an oven-dry basis.
• To control manufacturing processes influenced by moisture (e.g., printing stability, curl).
• To ensure reproducible moisture/dry-matter data for regulatory or contractual purposes.

Related standards

• ISO 638-2 - oven-drying for suspensions of cellulosic nanomaterials
• ISO 287 - moisture content of paper and board lots
• ISO 4119 - stock concentration of pulps
• ISO 186, ISO 7213, EN 17085 - sampling procedures referenced by EN ISO 638-1:2022

Keywords: EN ISO 638-1:2022, dry matter content, oven-drying method, paper board pulp, cellulosic nanomaterials, moisture content, 105 °C.