Fume Hood Selection


One of the first steps in fume hood management is the determination of which processes need to be performed under a hood. This is typically left to the chemical hygiene officer, a safety professional, or industrial hygienist. Processes involving volatile chemicals are the most commonly identified as requiring a fume hood for safe use. Other factors of chemical use such as how often this chemical is used, how much is being used, and the actual processes the chemical is subjected to have a bearing on this decision. Chemical exposure monitoring data from personal and area monitoring and lab procedure observation can also be part of this selection process. It is important not to underestimate the chemical exposure hazard level of a procedure.

Once the need for a hood is identified, the size and type must be selected. The size of the process and chemicals should be proportional to the fume hood selected as overcrowding in the hood is not desirable. Another important consideration is the type of fume hood selected. Hoods can be defined by sash (window) type; examples are vertical, horizontal, convertible, and walk-in. Hoods can also be defined by their exhaust system; examples are ductless, constant volume, variable air volume, and auxiliary air. Airflow monitors have become a popular and almost standard option for many new fume hoods. Because of the many options available, it is important for the fume hood program manager person to work with the laboratory manager and facility ventilation engineer to select the most appropriate combination and location for each fume hood. Perchloric acid, radioactive materials, or other agents requiring special consideration place an even higher level of safety concern and additional requirements for proper hood selection.