Design and evaluation of a prototype laboratory emission control device for use in a variable air volume, face velocity reducing system /
A prototype perforated backplane air baffle for a laboratory safety hood was designed, fabricated and its performance was evaluated experimentally. Relative to the historically poor performance of slot baffle design, the perforated metal created better laminar flow through the hood, and decreased t...
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| Format: | Thesis eBook |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Summary: | A prototype perforated backplane air baffle for a laboratory safety hood was designed, fabricated and its performance was evaluated experimentally. Relative to the historically poor performance of slot baffle design, the perforated metal created better laminar flow through the hood, and decreased turbulence in the form of vortices, ultimately resulting in better hood containment. New performance monitoring techniques were developed to aid in future testing of improved laboratory fume hood designs. Three methods were employed to evaluate the hood's performance: 1) face velocity testing, 2) tracer gas containment testing, and 3) smoke containment. Face velocity data was analyzed to evaluate turbulence and consistency across the hood face with the use of new statistical methods described in this thesis. It was determined that turbulence decreased and velocity uniformity increased as the average face velocity increased and as the open area of the hood face decreased. Tracer gas levels outside of the hood, in the operator's breathing zone, were kept below detectable levels (0.02 ppm) at all face velocity / sash position settings. In this work, a Hood Protection Factor was developed as a quantitative means to compare hood performance. The Hood Protection Factor is a true ratio of the contaminant concentration inside the hood exhaust duct to that in the operator's breathing zone, as both are measured values. A qualitative assessment of the hood's performance was completed by means of smoke testing. Smoke testing showed that smoke was captured / retained without escaping from the hood at all face velocity / sash position settings. Static pressure measurements were taken at the back panel of the hood. Graphical analysis of this data allowed visualization of the uniformity of suction across the perforated air baffle. The prototype backplane air baffle provided reduced turbulence at the hood face, allowing improved containment efficiency. New performance monitoring techniques and statistical evaluation methods were developed so health and safety professionals may better evaluate and design laboratory fume hoods. |
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| Item Description: | "Major subject: Industrial Hygiene". Vita. |
| Physical Description: | x, 193 leaves : illustrations ; 28 cm. Also available online. Issued also on microfiche from Lange Micrographics. |
| Bibliography: | Includes bibliographical references (leaves 51-53). |