Air volume measurement error in pumps with rotameters and high range "constant flow" pumps.
Weiss-SA; Beaulieu-HJ; Buchan-RM
Am Ind Hyg Assoc J 1982 Oct; 43(10):754-758
A study of air volume measurement error in pumps with rotameters and high constant flow pumps was conducted. Three brands of sampling pumps were used: an MSA model-G , a DuPont P-2500 constant flow sampler, and a Gelman Little Giant pump. Each was attached by manifold to four critical orifices matched at a flow rate of 2.0 liters per minute inside a specially designed exposure chamber. These were used to make up four sampling trains, one using the critical orifices, one the DuPont pump, and the other two consisting of MSA pumps. The critical orifices were connected to the Gelman pump. An aerosol of Portland cement dust was generated inside the chamber. All pumps were activated for 4 hours. One of the MSA sampling trains was adjusted for flow rate during sampling by adjusting the rotameter every 0.5 hours during sampling. Dust samples were collected on four closed face cassettes mounted on each of the four sides of the chamber. Air concentrations of the aerosols were determined by gravimetric analysis. Variations in concentration in each group of four were compared by determining the coefficients of variation. The coefficient of variation for dust collected in the MSA pump in which the rotameter was adjusted during sampling was 5.80 percent, versus 2.48 percent for the MSA pump that was not adjusted, 2.21 percent for the DuPont pump, and 2.20 percent for the critical orifice. The authors conclude that sampling pumps that are not adjusted during the sampling process tend to show less variation in the concentrations collected than pumps which are adjusted.
NIOSH-Publication; NIOSH-Grant; Air-sampling; Laboratory-testing; Airborne-particles; Air-sampling-equipment; Data-processing; Analytical-methods; Sampling-methods; Air-flow
American Industrial Hygiene Association Journal