ISO 1973 specifies a gravimetric method and a vibroscope method for the determination of the linear density of textile fibres applicable respectively to:
Useful data can be obtained on man-made fibres and, with less precision, on natural fibres. ISO 1973 only applies to fibres which can be kept straight and, in the case of bundles, parallel, during test preparation. ISO 1973 is properly applicable when the fibres are readily freed of crimp.
Note-
The methods in ISO 1973 are not applicable to tapered fibres.
The vibroscope method is not always applicable to hollow and flat (ribbon-like) fibres.
ISO 1973 on the determination of linear density - gravimetric method and vibroscope method is useful for:
The linear density of individual fibres is one of the most important physical characteristics in terms of processability and predictability of the next-step intermediate product, such as spun-yarns and nonwovens.
ISO 1973 specifies testing methods, such as air-permeability on test specimen consisting of mass of fibres (Micronaire).
ISO 1973 describes two measurement methods to determine the mass per unit length (determination of the linear density) using either a bundle of 50 fibres, or on individual fibres. While the first method determines an average value, only, in relatively short time, the second method measures the individual fibre fineness and therefore the statistical distribution of the laboratory sample, too.
BS EN ISO 1973:2021 is the third edition that cancels and replaces the second edition (ISO1973: 1995), which has been technically revised.
The main changes compared to the previous edition are as follows:
ISO 1973
EN ISO 1973