FIBER DIAMETER DISTRIBUTIONS IN TYPICAL MMVF WOOL INSULATION PRODUCTS

Abstract

In order to make available a consistent set of information about the fiber diameter distribution in man-made vitreous fiber (MMVF) products, we measured the length-weighted fiber diameter distribution in 22 samples of glass wool, rock and slag wool, refractory ceramic fiber, and special purpose fiber Insulation, from 11 different manufacturers. All of the samples were measured by the same procedures using light microscopy (LM), scanning electron microscopy (SEM), and gas adsorption (the BET method). We found that the length-weighted fiber diameters were neither approximately normally nor log normally distributed with arithmetic standard deviations typically 50–100% of the arithmetic mean. The geometric mean diameter was usually significantly smaller than the arithmetic mean diameter and the length-weighted median diameter lay between these two means. There was good agreement between the various means and standard deviations measured by LM and by SEM. In addition, the BET-measured fiber specific surface area agreed well with that calculated from the microscopically measured diameters. The length-weighted arithmetic mean diameters of the sampled glass wool products ranged from 1–8 µm, whereas for the rock and slag wool samples, it ranged from 2–5 µm.