Model 4500 Premier Dust and Opacity Monitor68B3-4 Isokinetic CalibrationThe Model 4500 Premier measures the opacity of dust and smoke emissions. As explained in the Referencemanual, this value is related to the dust density in the stack, through the Beer-Lambert law (see section C1-2). In order to measure the dust density, it is necessary to know the Dust Gain (parameter 'k'), whichrelates optical density to dust density. Dust Gain is found by comparing with the measured OpticalDensity/Dust Density found by an isokinetically sampled dust measurement.The Model 4500 Premier is designed to be easily calibrated relative to an isokinetic sample. Two methodsmay be used, depending on whether the instrument is to be calibrated relative to a single sample, ormultiple samples. A single sample is simple to collect and analyse, but more often a series ofmeasurements are taken under different load conditions or at different points across the diameter of thestack. This method gives a more accurate representation of the overall dust burden in the stack.
