Particle size distribution is determined using the Bahco Micro Particle Classifier or one of several sedimentation techniques. The data are used to compare dusts with respect to electrostatic collectibility based on the amount of material finer than 10 µm and 2 µm. The particle size distribution is also key information needed to model the precipitator performance. Particle size distribution as illustrated in Figure 4, is determined in accordance with ASME Power Test Code 28, Section 4. A sieve analysis had also been performed on the sample. Those data are also shown in Figure 4.