BS EN ISO 1833-17:2010

1   Scope This part of ISO 1833 specifies a method, using sulfuric acid, to determine the percentage of chlorofibres, after removal of non-fibrous material, in textiles made of binary mixtures of

— chlorofibres based on homopolymers of vinyl chloride (after-chlorinated or not)

and 

   
      
         

— cotton, viscose, cupro, modal, acetate, triacetate, polyamide, polyester, certain acrylic and certain modacrylic fibres. [The modacrylics concerned are those which give a limpid solution when immersed in concentrated sulfuric acid ( ρ = 1,84 g/ml).]

This method can be used, particularly in place of the methods described in [ISO 1833‑12](/search?q=ISO%C2%A01833%E2%80%9112) and [ISO 1833‑13](/search?q=ISO%C2%A01833%E2%80%9113), in all cases where a preliminary test shows that the chlorofibres do not dissolve
  completely either in dimethylformamide or in the azeotropic mixture of carbon disulfide
  and acetone.