BS ISO 21046:2018 pdf can be downloaded on www.freestandardsdownload.com,whose title is Silk — Test method for determining the size of silk yarns.
BS ISO 21046:2018 specifies the test method for determining the size of silk yarns in all types of package forms.
BS ISO 21046:2018 is applicable to various kinds of silk yarns.
Silk yarns are made of natural silk fibres, including raw silk, tussah silk, dupion silk, thrown silk, etc.Due to the intrinsic unevenness of the property of silk fibres and its manufacturing technique differing from yarns made of staple fibres, the size (linear density) deviation of the silk yarns, such as raw silk reeled from cocoon baves, is much bigger than that of the conventional yarns covered by ISO 2060.Therefore, when measuring the size of silk yarns, the sample quantity, sample length, test device,drying temperature, test items, calculation method of the results and tolerance for weighing errors are all different from that for the conventional yarns. These special requirements are not prescribed in ISO 2060.
BS ISO 21046:2018 covers special size test regulations for silk yarns which are not covered by ISO  2060.
Calculate the average size, size deviation, maximum size deviation, conditioned size and coefficient of
variation of size according to 8. 2 to 8.6, respectively, and round off the numerical values to the second decimal place.
An example of the test results is given in Annex C.