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Moment Method for Obtaining Particle Size Measures of Test Smokes



Thomas Cleary, D W. Weinert, George Mulholland


The number concentration, ionization chamber output, and mass concentration were recorded continuously for five different test smokes generated in the fire emulator/detector evaluator. The number and the mass concentrations are direct measures of the zeroth and third moments of the aerosol size distribution, while the ionization chamber output is correlated to a measurement of the first moment. The ratio of the first to zeroth moment and the cube root of the ratio of the third to zeroth moment yielded the count mean diameter (d10) and the diameter of average mass (d30) with peak values ranging from 0.20 [mu]m to 0.75 [mu]m for d10 and 0.25 [mu]m to 1.0 [mu]m for d30 for the smolder/pyrolysis smokes generated. Assuming a log-normal size distribution, estimates of the geometric standard deviation were computed from the two moment average diameter measurements. Additionally, comparisons of the mass median diameter estimated from moment analysis to the mass median aerodynamic diameter obtained from an 11-stage cascade impactor were made.
NIST Interagency/Internal Report (NISTIR) - 7050
Report Number


particle diameter, size distribution, smoke, smoke detector, smoldering


Cleary, T. , Weinert, D. and Mulholland, G. (2017), Moment Method for Obtaining Particle Size Measures of Test Smokes, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD (Accessed May 29, 2024)


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Created February 19, 2017