Volume 10, Issue 2 (March 1982)
A Rapid Technique for Estimating Fiber Lengths of Mineral Wools and Other Staples
A rapid and reproducible technique is described for estimating the mean length of staple fiber. A pad or felt prepared from the fiber is separated into two parts giving a torn edge, the diffuseness of which is proportional to the mean fiber length. This diffuseness may be quantified by illuminating the torn edge and measuring the changing light attenuation in a direction perpendicular to the line of separation. Absolute estimates of length are made by reference to calibration standards. The method is of particular value with brittle fibers such as mineral wools, for which it can otherwise be difficult to obtain reliable length data.
The techniques described in this paper form the basis of patent applications in several countries.