Hood Efficiencies of Vapor Degreasers Under Operating Conditions
Autor: | Richard S. Prodans, Richard A. Wadden, Margaret Lachman, Lorraine M. Conroy, Xioamin Yu, Peter A. Scheff, John E. Franke |
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Rok vydání: | 1995 |
Předmět: | |
Zdroj: | Journal of Environmental Engineering. 121:736-741 |
ISSN: | 1943-7870 0733-9372 |
DOI: | 10.1061/(asce)0733-9372(1995)121:10(736) |
Popis: | The objective of this research was to measure capture efficiency of local exhaust hoods used to control vapor degreasing tanks during normal operations and to compare the observed capture efficiencies to the American Conference of Governmental Industrial Hygienists (ACGIH) design criteria. Solvent emission rates and local exhaust hood capture efficiencies were measured at 15 vapor degreasers. The degreasers were located in 12 private industrial settings and studied under normal operating conditions. Where possible, hourly concentration data were collected during two 8-h shifts for each degreaser. Site-average fugitive emissions to the workspace (mean = 0.173 g/m{sup 2}/s, range = 0.001 {minus} 1.08 g/m{sup 2}/s) were in excellent agreement with previously reported tests for vapor degreasers under operating conditions. The ACGIH recommended flow of 0.25 m{sup 3}/s/m{sup 2} (50 cu ft/min/sq ft) of tank surface appears to be adequate for some conditions but inadequate for other conditions. An increase in flow, above design recommendations, did not necessarily improve hood performance. Hood capture efficiency was slightly correlated with hood face velocity, although there is significant variability in the data. Emissions of solvent to the workspace were only slightly correlated with duct emissions. This suggests that fugitive emissions are as strongly related to workmore » practices as they are to control device design.« less |
Databáze: | OpenAIRE |
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