Accession Number : AD0623295

Title :   THE MEASUREMENT OF PARTICLE SIZE OF FIRE FIGHTING DRY CHEMICALS.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Peterson,H. B.

Report Date : 27 SEP 1965

Pagination or Media Count : 20

Abstract : Four samples of potassium bicarbonate base fire extinguishing powders, 'Purple-K-Powder,' which had been ground to different degrees of fineness were analyzed for particle size characteristics by several different methods. These were the Blaine Fineness test, the Roller Particle Analyzer, the Coulter Counter, surface area by nitrogen adsorption, and mercury porosity. Comparisons were made of the results of the procedures. Highest values for specific surface were obtained by the nitrogen adsorption method followed by the Blaine, the Coulter, and then the Roller Methods, in that order. No conclusions were made as to which method gave the most accurate result for particle size, but it was found that the mean diameter was a better basis for comparing results than was the median diameter. Although the relationships of specific surface values among methods were non-linear over wide ranges, face values among methods were nonlinear over wide ranges, calibration curves were made to facilitate conversion. It was also concluded that specific surface values, as obtained by permeability with the Blaine method, were adequate for describing the desired size of particles for fire extinguishing purposes. (Author)

Descriptors :   (*FIRE EXTINGUISHERS, POWDERS), (*PARTICLE SIZE, CHEMICALS), POTASSIUM COMPOUNDS, BICARBONATES, PHYSICAL PROPERTIES

Distribution Statement : APPROVED FOR PUBLIC RELEASE