Calculating Weighted Commercial Regain across Multi Component Yarn Shipments
Calculate weighted regain by multiplying dry fiber fractions by standard regain rates, applying this factor to clean dry mass for final invoice weight.
Conditioning Atmosphere
Environmental Specification
Standardized temperature and humidity levels ensure that textile specimens reach a state of moisture equilibrium before physical testing begins. The conditioning atmosphere typically requires a temperature of 20 degrees Celsius and a relative humidity of 65 percent for most international standards. Accurate results for tensile strength and fabric weight depend entirely on the fiber reaching a stable state within these parameters.
Equilibrium Process
Natural fibers like cotton and wool absorb moisture from the air and change their physical dimensions and mechanical properties. Exposure to a conditioning atmosphere for a minimum of 24 hours allows these changes to level out so that tests are reproducible across different laboratories. Without this step, a fabric might appear heavier or stronger simply because the local weather was humid on the day of the test.
Laboratory Control
Precision air conditioning systems must circulate air around the samples to prevent pockets of stagnant humidity. Continuous logging of the conditioning atmosphere provides the evidence needed for laboratory accreditation and quality audits. If the sensors detect a deviation from the set points, the technician must restart the timing for the equilibrium process.
Compliance Requirement
ISO 139 defines the specific tolerances allowed for these environmental variables. Adherence to the conditioning atmosphere is the first requirement for any valid technical data sheet.