ISO 20193:2019 pdf free.Tobacco and tobacco products – Determination of the width of the strands of cut tobacco.
6 Procedure
6.1 General
For production control, samples can be selected just after cutting and measured rapidly in order to minimize the influence of ambient conditions.
If packed samples are analysed (for example in pouch, bag, box or cigarette pack), the atmosphere for the preparation of the strands and for the determination of the cut width of fine-cut tobacco shall be in accordance with the testing atmosphere specified in ISO 15592-2. For cigarettes, ISO 3402 shall be applied accordingly.
6.2 Sampling
Take the samples in accordance with ISO 15592-1 or ISO 8243.
6.3 Preparation of the samples
If samples are prepared from the packed product, a test portion of 50 g is taken.
If samples are prepared from the packed product, they shall be conditioned according to ISO 15592-2 for fine-cut tobacco or ISO 3402 for cigarettes. After conditioning, spread out the test portion.
Spread out the test portion as evenly as possible on an area of size A3 in accordance with ISO 216.
6.4 Preparation of the strands
From the test portion, randomly take 20 strands of at least 10 mm long which have been cut in parallel. Secure the strands to a sample holder (5.1]. Affix each strand to the surface of the sample holder perpendicular to the line(s) on the sample holder (some sample holders may have more than one line),taking care to ensure that the strands lie flat and are not twisted.
When the strands have been affixed to the sample holder, it is covered with a transparent strip in order to secure the strands’ position.When securing the strands, take care to avoid stretching. Artificial damage to the strands should be avoided.
6.5 Determination of cut width
6.5.1 General
Determine the cut width immediately after securing the strands.
Measure the cut width of each of the strands prepared in accordance with .A in accordance with the
procedure described in 6.5.2.
6.5.2 Single measurements
The single measurements shall be made either on or directly adjacent to a line on the sample holder (5.1). State the cut width to the nearest 005 mm.
7 Expression of results
Calculate the arithmetic mean from the individual measurements and report to the nearest 0,1 mm and the standard deviation to the nearest 0,01 mm.
Enter the evaluated data in a data sheet as illustrated in the example in Annex 13.
8 Repeatability and reproducibility
The difference between the mean of 20 measurements per holder, obtained within the shortest feasible time interval by the same operator working on identical sample material and using the same apparatus will exceed the repeatability limit, r, on average not more than once in 20 cases in the normal operation of the method.
The difference between two results, reported by two laboratories for the same sample material will
exceed the reproducibility limit, R, on average not more than once in 20 cases in the normal operation of the method.
An interlaboratory study involving 10 laboratories to determine the cut width yielded the values shown in Table 1 for the repeatability limit, r; and reproducibility limit, R, as well as for the standard deviations for repeatability and reproducibility, sp and Sp (see References [1] and [2]). Samples were conditioned according to ISO 15592-2 prior measurement.
The collaborative study has shown that the variability between the lines of a same holder could be
neglected compared with the variability between the strands. Measurement of 20 strands along a
single line is then sufficient.ISO 20193 pdf download.