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DC-83-10-5 -- Laboratory Air Systems--Further Testing
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DC-83-10-5 -- Laboratory Air Systems--Further Testing
Conference Proceeding by ASHRAE, 1983
R.L. Peterson, P.E.; E.L. Schofer, P.E.; D.W. Martin
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Tests to determine laboratory fume-hood performance under various conditions* were made using ASHRAE Standard 110P (August 1982). The method consists of introducing a refrigerant-12 air mixture through an ejector into a fume hood and detecting R-12 concentrations in the breathing zone of a mannequin. A hood-performance index was calculated from the âLOG10 of R-12 concentration outside the hood over R-12 concentration leaving the ejector. Tests of hood performance were made under four general laboratory configurations:
--Conventional room air supply, conventional hood
--Conventional room air supply, auxiliary air hood
--Diffuser duct air supply, conventional hood
--Diffuser duct air supply, auxiliary air hood
For each configuration, tests were done at various hood face velocities. In addition, some testing of the effects of auxiliary air velocity, percentage of auxiliary air, clutter, traffic, temperature differences between auxiliary air and laboratory air, and distance between vapor source and hood face were included in the study. Although many variables were not tested during this study, several trends were noted, including:
1. Improving the room air supply configuration produced a major improvement in the performance of a well-placed hood.
2. Use of auxiliary air in a lab with good air distribution had negligible effect on hood performance.
3. Use of auxiliary air in a lab with a conventional air-distribution system gave better or poorer results than a conventional hood, depending on face velocity and percentage of auxiliary air.
4. Hood performance did not correlate with hood face velocity over the range of 65 to 125 fpm (0.33 to 0.64 m/s).
Recommendations for further work in this area include testing various models of hoods in both as manufactured and as installed conditions to develop a data base for future laboratory designs.
*These tests are a part of the New York State University Construction Fund (SUCF) Project No. 16062.
Citation: Symposium, ASHRAE Transactions, 1983, vol. 89, pt. 2B, Washington, D.C.