Ventilation to eliminate oxygen deficiency in a confined space - Part II: noncubical models.
Appl Ind Hyg 1989 Oct; 4(10):260-268
A study of the ventilation characteristics needed to eliminate oxygen deficiency in confined spaces of noncubical shape was conducted. These experiments used confined space models in which oxygen deficiencies were created and subsequently removed by ventilation, with oxygen concentrations being monitored by electrochemical sensors. The noncubical shaped spaces investigated were rectangular; each represented an expansion of a cubical space in one or more axes. There were a total of 108 case studies which included variations in ventilation (two variations), volume flow rate (three variations), and inlet/outlet elevations (three variations). Oxygen deficiency was created by nitrogen release into the system. Results demonstrated that minimum oxygen recovery time constants increased with the volume flow rate in a linear manner. Depthwise cubical expansions leading to rectangles had recovery times which were generally faster than those observed in sideways cubical expansions. Data also showed that mechanical ventilation or low ventilation elevations resulted in faster recovery times. The authors recommend that more emphasis should be place on mechanical ventilation as a primary means of control for potentially hazardous atmospheres in confined spaces.
NIOSH-Publication; NIOSH-Grant; Ventilation-equipment; Breathing-atmospheres; Confined-spaces; Mathematical-models; Workplace-studies; Oxygen-deficient-atmospheres; Air-quality-control
Environmental & Indust Health University of Michigan 1420 Washington Heights Ann Arbor, MI 48109-2029
Applied Industrial Hygiene
University of Michigan at Ann Arbor, Ann Arbor, Michigan