Overview
EN ISO 187:2022 - "Paper, board and pulps - Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples" defines the standard atmospheres, conditioning procedure and monitoring required to bring pulp, paper and board samples to a reproducible moisture-equilibrium state prior to testing. The standard addresses temperature and relative humidity (RH) control, preconditioning to avoid sorption/desorption hysteresis, acceptable limits, and reporting requirements. It is used to ensure comparable, repeatable test results across laboratories and production environments.
Key topics and technical requirements
- Standard test atmosphere: (23 ± 1) °C and (50 ± 2) % RH.
- Alternative for tropical climates: (27 ± 1) °C and (65 ± 2) % RH.
- Equilibrium (conditioning) definition: achieved when two consecutive weighings at least 1 hour apart differ by ≤ 0.25 % of the specimen mass.
- Preconditioning: when hysteresis is significant, precondition samples for 24 h at 10–35 % RH and temperature ≤ 40 °C (laboratory sheets made per ISO 5269‑1 / ISO 5269‑3 are not preconditioned).
- Conditioning practice: ensure free air access to all specimen surfaces; minimize handling and avoid breathing on test areas.
- Typical conditioning times: ~4 h with good circulation for ordinary paper; 5–8 h for higher grammage; boards or treated materials may require 48 h or longer.
- Monitoring: measure and record temperature and RH as described in Annex A; a test atmosphere is acceptable only if measurements stay within specified limits.
- Excursions and contamination: short-term excursions that affect equilibrium are not permitted. If atmosphere exceeded limits (or RH > 75 %) samples must be reconditioned or discarded if dried-in strain may have been released.
- Test report requirements: must reference EN ISO 187:2022 and record conditioning atmosphere used, conditioning time, preconditioning status, any deviations, and test date.
Applications and users
- Quality control and testing laboratories in pulp, paper and board manufacturing
- R&D and materials testing facilities validating mechanical, optical or physical properties
- Converters, printers and packaging companies needing standardized sample conditioning
- Certification bodies and standards developers ensuring repeatable inter-laboratory comparisons
Using EN ISO 187:2022 helps reduce variability from moisture content, improving reliability of test data such as tensile strength, thickness, dimensional stability and other moisture-sensitive properties.
Related standards
- ISO 5269-1 and ISO 5269-3 (laboratory sheet preparation - referenced in EN ISO 187:2022)
- Other ISO test methods for paper and board where conditioning is a prerequisite
Keywords: EN ISO 187:2022, ISO 187:2022, standard atmosphere, conditioning, testing, paper, board, pulps, relative humidity, temperature, sample conditioning, monitoring.