ISO standards to determine the linear density of linen fibers
There are two key ISO standards used to determine the linear density of linen fibers:
- ISO 1973:2021 (and its previous edition ISO 1973:1995): Textile fibers — determination of linear density — gravimetric method and vibroscope method.
This standard specifies two methods for determining the linear density (mass per unit l length) of textile fibers, including linen.
- Gravimetric method: This direct method involves weighing a known length of fibers. It's applicable to bundles of fibers.
- Vibroscope method: This method measures the linear density based on the vibration frequency of a fiber under tension. It's applicable to individual fibers.
The standard is applicable to fibers that can be kept straight and, in the case of bundles, parallel during testing. It's most accurate for man-made fibers but can also be used for natural fibers like linen, although with potentially less precision.
- ISO 1144:2016 (and its previous edition ISO 1144:1973): ‘Textiles — universal system for designating linear density (Tex System).
This standard establishes the Tex System, which is the recommended universal system for expressing the linear density of all types of textile fibers, including linen, as well as yarns and other intermediate products.
It defines the tex unit as the mass in grams per 1,000 meters (1 km) of the textile material. Sub-multiples and multiples of the tex unit (e.g., decitex, millitex, kilotex) are also defined.
ISO 1144 also provides principles for using the Tex System and includes conversion tables for converting linear density values from other traditional numbering systems (counts) to the Tex System.
Therefore, to determine the linear density of linen fibers according to ISO standards, you would use the test methods outlined in ISO 1973, and the result would ideally be expressed using the Tex System as defined in ISO 1144.