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Factors Affecting the Design of Local Exhaust Ventilation for the Control of Contaminants from Hand-Held Sources.

PB91189001

Publication Date	1990
Personal Author	Flynn, M. R.; Shelton, W. K.
Page Count	27
Abstract	Measurements were made of tracer gas concentrations in the breathing zone of a mannequin positioned in front of flanged circular exhaust hoods arranged in various configurations. The gas was generated from a hand held source. The results indicated that the mannequin was subjected to less hazardous conditions when placed to the side of the hood rather than in the conventional orientation with the source between the body and the hood. The experiments showed that there was an increase in exposure as the distance decreased between the source and the hood for small hoods. This was an unexpected finding. The authors stress the importance of considering worker practices when evaluating the effectiveness of engineering controls. Factors which determine the exposure of the individual working in the hood include the mass flow of pollutant, the source configuration and momentum, the hood air flow, the hood size and shape, the distance of the worker from the hood, and the position of the worker and source with respect to the hood.
Keywords	Ventilation Industrial hygiene Occupational exposure Exhaust hoods Design Air flow Air sampling Air pollution control Laboratory tests Simulation Indoor air pollution Local exhaust ventilation
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	68A - Air Pollution & Control 94D - Job Environment 41I - Job Environment
Corporate Authors	North Carolina Univ. at Chapel Hill. Dept. of Environmental Sciences and Engineering.; National Inst. for Occupational Safety and Health, Cincinnati, OH.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
NTIS Issue Number	199116

Factors Affecting the Design of Local Exhaust Ventilation for the Control of Contaminants from Hand-Held Sources.

Factors Affecting the Design of Local Exhaust Ventilation for the Control of Contaminants from Hand-Held Sources.
PB91189001

Publication Date	1990
Personal Author	Flynn, M. R.; Shelton, W. K.
Page Count	27
Abstract	Measurements were made of tracer gas concentrations in the breathing zone of a mannequin positioned in front of flanged circular exhaust hoods arranged in various configurations. The gas was generated from a hand held source. The results indicated that the mannequin was subjected to less hazardous conditions when placed to the side of the hood rather than in the conventional orientation with the source between the body and the hood. The experiments showed that there was an increase in exposure as the distance decreased between the source and the hood for small hoods. This was an unexpected finding. The authors stress the importance of considering worker practices when evaluating the effectiveness of engineering controls. Factors which determine the exposure of the individual working in the hood include the mass flow of pollutant, the source configuration and momentum, the hood air flow, the hood size and shape, the distance of the worker from the hood, and the position of the worker and source with respect to the hood.
Keywords	Ventilation Industrial hygiene Occupational exposure Exhaust hoods Design Air flow Air sampling Air pollution control Laboratory tests Simulation Indoor air pollution Local exhaust ventilation
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	68A - Air Pollution & Control 94D - Job Environment 41I - Job Environment
Corporate Authors	North Carolina Univ. at Chapel Hill. Dept. of Environmental Sciences and Engineering.; National Inst. for Occupational Safety and Health, Cincinnati, OH.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
NTIS Issue Number	199116