Modern Instruments to Measure Fiber Length

There are only four modern instruments used to measure fiber length that are approved by the International Wool Testing Organisation (IWTO) and the American Society for Testing and Materials (ASTM). All of the testing must occur in a controlled-laboratory setting. The results of these tests help breeders and ranchers ascertain the success of their breeding and raising process with wool-producing herds.

  1. Optical Fibre Diameter Analyser

    • The OFDA 100 is a digital video analyzer made by BSC Electronics and approved in 1995 by the IWTO for use in measuring fiber length and estimating volume. The OFDA 100 uses software programs from developers like IBM to perform and analyze fiber for mass volume applications, such as estimating wool yield for entire herds.

    Laser Scan

    • The Sirolan Laser Scan measures samples of fiber measured and cut to 2-millimeter lengths using a micron meter to find the diameter of the fiber sample. From this measurement, the Laser Scan can then project the length of the fiber and yield the sample it may produce.

    Airflow

    • Airflow methods produce rough estimates of fiber length. Wool samples are placed in a sealed tube and the airflow resistance of the sample is measured. Based on the measured resistance, a general determination of the diameter of the fiber is made. This general diameter is then used to estimate the yield length of the fiber based on comparison to tables that list diameter to length (yield) ratios.

    Projection Microscopes

    • Projection microscopes (microprojection) are considered the only reliable measuring device for fiber length and diameter. Samples can be magnified to 500 times their original size and measured with a micron scale. Microprojection creates the standards that other methods of measuring are compared against. It is prohibitively expensive to use for most purposes.