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A new, automated method for testing particulate respirators.

Remiarz RJ; Agarwal JK; Nelson PA; Moyer E
J Int Soc Respir Prot 1984 Jul; 2(3):275-287
A new automated system for testing particulate respirator filters was described. The system utilized a condensation nucleus counter (CNC) containing three major components: a saturator tube, condenser tube, and sensor. The system could operate in two modes, a count mode that counted electric pulses generated by light scattered from individual droplets at particle concentrations below 1000 particles per cubic centimeter (particle/cm3) and a photodetector mode that counted particles at concentrations above 1000particle/cm3. The CNC was interfaced to a microcomputer system that monitored, read, and controlled the instruments. The system monitored respirator efficiency, flow rates, and pressure drops over time; it could test three respirators simultaneously. When tested with high efficiency filters at flow rates of 16 to 85 liters per minute using a sodium-chloride aerosol, mean efficiencies of 99.995963 to 99.999986 percent were measured. A reproducibility study using 19 samples gave a mean filter efficiency of 99.960 percent and a mean standard deviation of 10x10(-4). The authors conclude that the CNC system can measure respirator count efficiencies over 99.99999 percent using any challenge aerosol.
Testing-equipment; Laboratory-testing; Respiratory-protective-equipment; Industrial-safety; Equipment-design; Air-flow; Aerosol-particles
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Journal Article
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Journal of the International Society for Respiratory Protection
Page last reviewed: February 11, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division