ISO 2916:1975 pdf download.Wool-Determination of alkali content.
ISO 2916 is based on the IWTO test method 21-69 drawn up by the International Wool Textile Organization.
1 SCOPE AND FIELD OF APPLICATION
ISO 2916 specifies a method for the determination of the alkali content of wool.
The method is applicable to undyed wool in any form; for example, loose fibres, card sliver, tops, yarn or fabric. It can be used with dyed wool if the amount of dye extracted in the course of the test does not affect the determination of the endpoint of the titration.
ISO 2916 is based on the IWTO test method 21-69 drawn up by the International Wool Textile Organization.
1 SCOPE AND FIELD OF APPLICATION
ISO 2916 specifies a method for the determination of the alkali content of wool.
The method is applicable to undyed wool in any form; for example, loose fibres, card sliver, tops, yarn or fabric. It can be used with dyed wool if the amount of dye extracted in the course of the test does not affect the determination of the endpoint of the titration.
An interlaboratory trial was carried out by a Working Group using three wools of different alkali contents. Nine laboratories participated. The statistical evaluation of the resulting 3 X 9 X 2 values (each laboratory carried out a double test on each wool) produced the values summarized in the following table.
These data enable an estimation to be made of the confidence limits to be expected in a determination of alkali content according to the method specified.
A.1 CONFIDENCE LIMITS FOR THE RESULTS OF ONE LABORATORY
If the interlaboratory variance is not taken into consideration (comparison within one laboratory), the confidence limits, T1, of the mean for the laboratory are
in which the participating I laboratories each carried out k tests. When i = 1, the confidence limits for individual laboratories with interlaboratory variance taken into account are obtained.
Approximate numerical values for sL and SR are obtained from the above table.ISO-2916-1975