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Division I.8.2

United Kingdom

Original text. Later amendments are not shown.

Calculation of percentage of insoluble component on clean, dry mass basis, with adjustment by conventional factors and, where appropriate, correction factors for loss of mass during pre-treatment:

P 1 A % = 100 P 1 1 + a 1 + b 1 100 P 1 1 + a 1 + b 1 100 + 100 − P 1 1 + a 2 + b 2 100

where

P1A%

  • is the percentage of insoluble component adjusted by agreed allowances and for loss in mass during pre-treatment,

    • P1

  • is the percentage of clean dry insoluble component as calculated from the formula shown in I.8.1,

    • a1

  • is the agreed allowance for the insoluble component (see Annex IX),

    • a2

  • is the agreed allowance for the soluble component (see Annex IX),

    • b1

  • is the percentage loss of insoluble component caused by pre-treatment,

    • b2

  • is the percentage loss of soluble component caused by pre-treatment.

    • The percentage of the second component is P2A % = 100 – P1A %.

    Where a special pre-treatment has been used, the values of b1 and b2 shall be determined, if possible, by submitting each of the pure fibre constituents to the pre-treatment applied in the analysis. Pure fibres are those free from all non-fibrous material except that which they normally contain (either naturally or because of the manufacturing process), in the state (unbleached, bleached) in which they are found in the material to be analysed.

    Where no clean separate constituent fibres used in the manufacture of the material to be analysed are available, average values of b1 and b2 as obtained from tests performed on clean fibres similar to those in the mixture under examination, shall be used.

    If normal pre-treatment by extraction with light petroleum and water is applied, correction factors b1 and b2 may generally be ignored, except in the case of unbleached cotton, unbleached flax (or linen) and unbleached hemp, where the loss due to the pre-treatment is conventionally taken as 4 %, and in the case of polypropylene, where it is taken as 1 %.

    In the case of other fibres, losses due to the pre-treatment are conventionally disregarded in calculations.