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Abstract
The design and performance of typical laboratory hoods found in a large biomedical research facility are evaluated. The objective of the project is to examine specific design parameters and work practices which affect hood performance and result in worker exposure. The field work includes quantitative and qualitative evaluation of three auxiliary air supply hoods.
Hoods were challenged with smoke which permits observation of air flow within them. Measurements were taken to characterize the distribution of velocity across the hood face. Finally, hoods were challenged with sulfur hexafluoride tracer gas, and peak concentrations leaking from them were measured in the breathing zone of a life-size mannequin. Variables affecting laboratory hood performance that are examined here include: baffle position, face velocity, and tracer gas challenge height. Each of these has a significant effect on the containment efficiency of the hood.
The tests enable determination of appropriate operating conditions, and identify proper work practices for reducing potential employee exposure. These parameters can be controlled by the employees, health and safety personnel, and facility engineers to help provide optimum performance.