# Regulation (EU) No 1007/2011 of the European Parliament and of the Council of 27 September 2011 on textile fibre names and related labelling and marking of the fibre composition of textile products and repealing Council Directive 73/44/EEC and Directives 96/73/EC and 2008/121/EC of the European Parliament and of the Council (Text with EEA relevance), Division I.8.1

Extent: E+W+S+N.I.

Calculation of percentage of insoluble component on clean, dry mass basis, disregarding loss of fibre mass during pre-treatment:
P 1 % = 100 rd m where
P1% is the percentage of clean, dry insoluble component,
m is the dry mass of the test specimen after pre-treatment,
r is the dry mass of the residue,
d is the correction factor for loss in mass of the insoluble component in the reagent during the analysis. Suitable values for ‘d’ are given in the relevant section of each method.
Of course, these values for ‘d’ are the normal values applicable to chemically undegraded fibres.

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Source: https://www.legislation.gov.uk/eur/2011/1007/annex/VIII/chapter/2/division/1/division/I/division/I.8/division/I.8.1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2011-1007/annex-VIII/chapter-2/division-1/division-I/division-I.8/division-I.8.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.