Differential pressure as a means of estimating respirable dust mass on collection filters.
Dobroski-H Jr.; Tuchman-DP; Vinson-RP
Appl Occup Environ Hyg 1997 Dec; 12(12):1047-1051
The use of differential pressure measurements to estimate respirable dust mass on collection filters was examined. Polyvinylchloride (PVC) surface collecting filters, glass fiber depth filters, and nylon membrane surface collection filters were sealed in sampling cassettes. A laboratory differential pressure apparatus was used to measure the differential pressure of the cassettes before and after exposure to coal and rock dusts at various flow rates and sampling times. Dusts were generated in test chambers using either a fluidized bed dust generator or a mechanical dust mill. Either a tapered element oscillating microbalance aerosol monitor or a real time aerosol dust monitor was used to check dust concentrations in the test chambers. Differential pressure was poorly correlated with dust mass for commercially available sampling cassettes loaded with PVC surface collecting filters. The aluminum mask and check valves of the cassettes interfered with dust depositing, which decreased the predictability of the differential pressure response. In addition, differential pressure measurements were unable to accurately estimate the dust mass collected on PVC filters installed in three piece polystyrene cassettes. For various mixtures of coal and rock dust sampled using glass fiber depth filters, differential pressure measurements were highly correlated with dust mass, with an overall coefficient of 0.88. For various mixtures of coal and rock dust sampled using nylon membrane surface collection filters, poor correlations between differential pressure and dust mass were determined. The authors conclude that the glass fiber depth filter offers the best differential pressure response for estimating the mass of dust samples.
NIOSH-Author; Coal-dust; Respirable-dust; Dust-sampling; Dust-samplers; Gravimetric-analysis; Analytical-methods; Sampling-methods; Sampling-equipment; Filter-materials; Air-filters; Membrane-filters; Air-flow
Applied Occupational and Environmental Hygiene