The Relationship Between Mean Fibre Diameter Measurements by Airflow and Laserscan for South African Wools

Abstract

Laserscans have been in operation at Wool Testing Bureau S.A. (WTB) for the past six years. An earlier paper  in April 2000 presented the relationship between Airflow and Laserscan for South African Wools. The gradual changes in the South African Wool Clip and improvements in the Laserscan Technology since then has necessitated the research conducted in this report.

During the IWTO Congress in Hobart 2005, it was decided to implement the TEAM-3 formula as from 1 July 2006. One of the variables in the TEAM 3 formula requires the Coefficient of Variation of Mean Fibre Diameter. This implies that if a Test House reports the Hauteur value as additional information, Mean Fibre Diameter (MFD) measurements will be made according to IWTO-12 (Laserscan) or IWTO-47 (OFDA). Currently WTB uses Airflow (IWTO-28) as the default MFD Test Method.

This report summarises the relationship between Mean Fibre Diameter (MFD) measurements by Airflow (IWTO-28) and Laserscan (IWTO-12) for South African Wools. An overall difference of -0.15µm, independent of fibre diameter, was found. The trial was conducted on Commercial samples representative of the entire South African Clip. This difference is similar to reports already presented to IWTO from New Zealand and Australia. It is recommended that the IWTO Core Test Regulations and the IWTO Blue Book be amended to allow Certification of South African Wools on Laserscan (IWTO-12).

Citation

"The Relationship Between Mean Fibre Diameter Measurements by Airflow and Laserscan for South African Wools", W.A. Heath, J.W. Barkhuizen, O.E. Wright, Report 03, Raw Wool Group, IWTO, Cairo, May 2006