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Ventilation for Work in Confined Spaces.

PB92108455

Publication Date	1991
Personal Author	Garrison, R. P.
Page Count	78
Abstract	A series of studies was conducted involving experimental testing and computer modeling to evaluate ventilation characteristics and improve design methods for confined spaces (CS). The models were developed in an effort to predict CS ventilation effectiveness and to advance ventilation design technology. Multicellular models of CS ventilation were programmed and tested for two basic variations. Model 1 used experimental data and approximations to represent airflow in the CS. Model 2 used airflow characteristics predicted by another computer model. Mechanical ventilation was far more effective than natural ventilation could have been in CS. In general supply ventilation was more effective than exhaust ventilation. The inlet/outlet elevation had a significant effect on effectiveness with low inlet/outlet elevations being generally more effective in diluting contaminants. Ventilation time decreased with increasing flow rate, but not usually in a linear manner. Significant, variable, and somewhat inconsistent effects on ventilation time were observed by changing the CS model shape. Ventilation effectiveness characteristics varied significantly with contaminant stratification caused by heavier than air contaminants. Dilution ventilation characteristics for simulated toxic concentrations were similar to those for oxygen deficiency caused by nitrogen (7727379).
Keywords	Environmental surveys Occupational safety and health Toxic substances Ventilation Confined environments Nitrogen Air flow Computerized simulation Air pollution control Guidelines Tables(Data) Indoor air pollution Design criteria Performance evaluation Models Experimental design Air quality CAS 7727-37-9
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	57U - Public Health & Industrial Medicine 68G - Environmental Health & Safety 68A - Air Pollution & Control 94D - Job Environment
Corporate Authors	Michigan Univ., Ann Arbor. School of Public Health.; National Inst. for Occupational Safety and Health, Rockville, MD.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Rockville, MD.
Document Type	Technical Report
NTIS Issue Number	199202

Ventilation for Work in Confined Spaces.

Ventilation for Work in Confined Spaces.
PB92108455

Publication Date	1991
Personal Author	Garrison, R. P.
Page Count	78
Abstract	A series of studies was conducted involving experimental testing and computer modeling to evaluate ventilation characteristics and improve design methods for confined spaces (CS). The models were developed in an effort to predict CS ventilation effectiveness and to advance ventilation design technology. Multicellular models of CS ventilation were programmed and tested for two basic variations. Model 1 used experimental data and approximations to represent airflow in the CS. Model 2 used airflow characteristics predicted by another computer model. Mechanical ventilation was far more effective than natural ventilation could have been in CS. In general supply ventilation was more effective than exhaust ventilation. The inlet/outlet elevation had a significant effect on effectiveness with low inlet/outlet elevations being generally more effective in diluting contaminants. Ventilation time decreased with increasing flow rate, but not usually in a linear manner. Significant, variable, and somewhat inconsistent effects on ventilation time were observed by changing the CS model shape. Ventilation effectiveness characteristics varied significantly with contaminant stratification caused by heavier than air contaminants. Dilution ventilation characteristics for simulated toxic concentrations were similar to those for oxygen deficiency caused by nitrogen (7727379).
Keywords	Environmental surveys Occupational safety and health Toxic substances Ventilation Confined environments Nitrogen Air flow Computerized simulation Air pollution control Guidelines Tables(Data) Indoor air pollution Design criteria Performance evaluation Models Experimental design Air quality CAS 7727-37-9
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	57U - Public Health & Industrial Medicine 68G - Environmental Health & Safety 68A - Air Pollution & Control 94D - Job Environment
Corporate Authors	Michigan Univ., Ann Arbor. School of Public Health.; National Inst. for Occupational Safety and Health, Rockville, MD.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Rockville, MD.
Document Type	Technical Report
NTIS Issue Number	199202