Fleece Testing Definitions

FD

 Fibre Diameter The mean (average) micron result of a sample.
SD Standard Deviation Measures in microns the spread of fibres either side of the mean FD in which 68% (two-thirds) of the fibres lie. The lower the SD the more uniform the wool.
CV Coefficient of Variation The CV is the SD divided by the mean FDx100. CV measures the FD variability as a percentage. CV tends to fall in the range of 15% to 30%, with 15% being very uniform wool, whilst 30% is highly variable wool.
%>30.5 Fibres greater than 30.5um Measures the percentage of fibres above 30.5 microns. Results greater than 5% may cause the pricklel effect.
CF Comfort Factor

Measures the percentage of fibres below 30.5 microns. Calculated as 100 minus the percentage of fibres below 30.5 microns.
SF Spinning Fineness Calculated using the mean FD and CV to determine an "effective" fineness. This figure gives a measure of spinning performance. For wools of any particular micron the spinning performance decreases as the CV increases.
CURV Curvature Measures how rapidly a fibre bends along an average standard short length of the fibre. Expressed as degrees of curve per millimetre of fibre (deg/mm). Curvature measurements usually range between 70 and 150 deg/mm. Curvature strongly relates to crimp frequency, therefore the higher the curvature the higher the crimp frequency.