Semester

Summer

Date of Graduation

2010

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Industrial and Managements Systems Engineering

Committee Chair

Steven E. Guffey.

Abstract

In industry, benchtop enclosing hoods are critical in protecting workers from airborne contaminants, but there is little research published about industrial enclosing hoods. Almost all hood research has been done on laboratory fume hoods.;A tracer gas method was used to study the performance of a single benchtop enclosing hood tested inside a 9 ft high, 12 ft wide and 40 ft long wind tunnel. Freon-134a concentrations were measured on an anthropometrically scaled, heated, breathing manikin holding a source between its hands while standing at the enclosing hood's face. Samples were taken at the nose (Cnose), mouth (Cmouth), inlet of the wind tunnel (Cambient), downstream of the wind tunnel (Cdownstream) and the exhaust duct (Cduct). Each location was sampled at 0.15 LPM for 20 minutes.;The work was divided into two studies, each having a complete factorial design and two replicates of each treatment combination. Study-I tested the effects of hood face velocity at five levels (111, 140, 170, 200 and 229 fpm) and wind tunnel cross-draft velocity at five levels (14, 26, 36, 46 and 57 fpm) on the plain enclosing hood performance. Study-II determined the effects of different interventions added to the face of the same enclosing hood.;The results showed that hood face velocity, wind tunnel cross-draft velocity and different interventions had significant effects on the concentrations at Cnose and Cmouth. Flanges, cowls, and most other interventions failed to consistently reduce exposures and often exacerbated them. However, the customized sash reduced exposures to nearly zero. It is also found that higher face velocity and cross-draft velocity were associated with lower Cnose and Cmouth.

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