Factors Affecting Hooding

Major factors affecting hood efficiency included location of hood, location of sources of room air supply, hood configuration, and clutter and obstructions in the hood chamber. 

Hood, A.V. 1984. Possible factors affecting sulfur dioxide inhibition of lactic acid bacteria in newly-fermented wines. Malolactic Fermentation. Aust. Soc. for Viticulture and Oenology, Inc. 

This has been covered briefly before in discussing the location of the hood within a laboratory and the effects of doors, windows, air supply inlets, and traffic. In recent years, there has been substantial research on the factors that affect the performance of fume hoods, what are suitable designs, sizes, means of controlling them, what external factors influence their efficacy, the implications on building energy efficiency by their use, the dispersal of their exhausts, the materials of which they are constructed among others. The following sections will address some of these issues. 

C.3 Factors That Affect Fume Hood Performance... 

Hood efficiency was not affected by varying face velocities between 0.3 to 0.63 meters per second (60 to 124 Ifpm), if all other factors were unchanged. 

The algebraic relationship between experimentally determined rate constants (k) as a function of factors that affect the reaction rate, such as the concentration of reaction ingredients, including catalysts and temperature, is defined as empirical kinetic equation. The validity of an empirical kinetic equation is solely supported by experimental observations and, thus, its authenticity is beyond any doubt as far as a reliable data fit to the empirical equation is concerned. However, the nature and the values of calculated empirical parameters or constants remain obscure until the empirical kinetic equation is justified theoretically or mechanistically. The experimental determination of the empirical kinetic equations is considered to be the most important aspect of the use of kinetic study in the mechanistic diagnosis of the reactions. The classical and perhaps the most important empirical kinetic equation, determined by Hood in 1878, is Equation 7.8. 

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