Length measurement
In general a longer average fibre length is to be preferred because it confers a number a advantages Firstly, longer fibres are easier to process. Secondly, more even yarns can be produced form them because there are less fibre ends in a given length of yarn. Thirdly, a higher strength yarn can be produced from them for the same level of twist. Alternatively a yarn of the same strength can be produced but with a lower level of twist, thus giving a softer yarn.
Mean Length
When calculating the means length . There are in fact three possible ways of deriving the mean length:
1. Mean length based on number of fibers (unbaised mean length) L
2. Mean length based on fiber cross-section (cross-section biased mean length) Hauteur H.
3. Mean length based on fiber mass (mass-biased mean length) Barbe B.