Overview - EN ISO 139:2005 (Textiles - Standard atmospheres for conditioning and testing)
EN ISO 139:2005 (ISO 139:2005) is the CEN-endorsed international standard that defines standard atmospheres for conditioning textiles and for determining their physical and mechanical properties. The document specifies both a primary standard atmosphere and a standard alternative atmosphere (usable only by agreement), describes tolerance zones, monitoring and control requirements, and reporting elements for laboratory testing of textile materials.
Key topics and technical requirements
- Standard atmospheres
- Primary: 20.0 °C and 65.0 % relative humidity (RH).
- Alternative (by agreement): 23.0 °C and 50.0 % RH.
- Tolerances
- Temperature: ±2.0 °C
- Relative humidity: ±4.0 %
- Tolerances account for measurement uncertainty (see Annex B and introduction).
- Measuring device requirements
- Resolution: 0.1 °C (temperature), 0.1 % RH (humidity) or better.
- Uncertainty: ±0.5 °C (temperature), ±2.0 % RH (humidity) or better.
- Calibration and regular determination of measurement uncertainty are required.
- Control and monitoring
- Continuous monitoring with suitable sensors/recorders; sampling frequency must detect short-term out-of-tolerance events (Annex A).
- Spatial checks throughout the conditioned space (minimum density specified in Annex A).
- Monitoring devices must be separate from HVAC control sensors.
- Conditioning procedures
- Pre-conditioning, if used, should bring specimens near equilibrium in low-humidity conditions (RH 10–25 %, temperature not exceeding 50.0 °C).
- Equilibrium criterion: successive weighings at 2-hour intervals showing no progressive mass change > 0.25 %.
- Test report essentials
- Specimen identification, reference to ISO 139:2005, details of conditioning atmosphere, and any deviations.
Practical applications and users
EN ISO 139:2005 is used to ensure repeatable, comparable textile test results across:
- Textile testing laboratories and accreditation bodies
- Manufacturers and suppliers specifying test conditions for quality control
- Research and development teams studying material properties
- Procurement and certification entities that require standardized conditioning before property evaluation
Adoption of the standard improves comparability of tensile tests, dimensional stability measurements, moisture-related behavior and other textile performance tests by ensuring consistent temperature and humidity control.
Related standards
- ISO 14253-1 - decision rules and measurement uncertainty considerations (referenced for tolerance/conformity concepts)
- ISO 3534-2 - applied statistics vocabulary
- International vocabulary of metrology (VIM)
Keywords: EN ISO 139:2005, ISO 139:2005, standard atmospheres, textiles, conditioning and testing, relative humidity, temperature control, textile testing laboratory.
