Effects of Ceiling Height on Determining Calculated Intake Air Velocities for Biological Safety Cabinets
| Autor: | John M. Eagleson, David G. Stuart, Robert L. Jones, Dennis Eagleson |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | Applied Occupational and Environmental Hygiene. 6:683-688 |
| ISSN: | 1521-0898 1047-322X |
| Popis: | A potential problem exists with the certification of Class II, Type A, biological safety cabinets using the standard method for deriving cabinet intake velocity. It has been found that the cabinet air flow balance is affected by low ceiling height over the cabinet exhaust opening. Two different Class II, Type A, cabinets and two air flow measuring methods were compared as a false ceiling apparatus was positioned from 5.2 to 35.6 cm (2–14 in.) above the cabinet exhaust opening. The results showed that a ceiling height as low as 5.2 cm (2 in.) above the exhaust plenum had no effect on actual cabinet air flow. Results also indicated two measuring methods yielded different results throughout the range of ceiling heights. Both measuring methods demonstrated a strong negative correlation (-0.9) for derived cabinet intake air velocity as a function of increased ceiling height. The precisely determined, yet inaccurate, operational setpoint (with the low ceiling in place) versus the actual operational set... |
| Databáze: | OpenAIRE |
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