Ductless fume hoods are designed in much the same manner as ducted fume hoods with similar focus on internal airflow testing and face velocity. However, because ductless technology incorporates individual fans in each unit to ensure the proper amount of airflow, the internal design and airflow of the cabinets is vitally important for operator and equipment safety.
Cabinet work zones are designed to be aerodynamic, with smooth internal surfaces that are free of obstructions, to ensure uninterrupted airflow through the cabinet. All cabinet openings are airtight to minimize airflow dead zones and ensure contaminated air flows uninhibited through the specialized carbon filter.
In addition to ductless fume hood cabinet airflow, the work surface is designed to be chemical and abrasion resistant and will never chip. The outer edge of the work surface has a lip to ensure spills are contained on the work surface. The lip also has a curved edge to minimize turbulence to incoming airflow.
Further cabinet design considerations include airflow and face velocity, ergonomics and portability features.
Airflow and Face Velocity
Per a variety of international standards, inflow air moves from the ambient environment into the work zone of the ductless fume hoods through the cabinet opening at an average velocity of 100 fpm. This creates a negative pressure zone in the cabinet work area, transports contaminated air through the carbon filter to remove contamination and then pushes the filtered air back into the laboratory environment. Energy efficient, centrifugal blowers provide long mechanical life and dependable performance in a variety of conditions.
While ergonomics are an important consideration for any piece of laboratory equipment, operator comfort is exceptionally important in the case of ductless fume hoods. Fume hoods are often used for a high percentage of the day and can contain some of the most delicate laboratory processes. Ensuring operator comfort and ease of use is of paramount concern for laboratory equipment manufacturers.
Noise and Vibration.
Ductless fume hoods contain internal fan systems, but due to the centrifugal design of the blowers, noise and vibration are kept to a minimum.
A sloping front design minimizes glare on the view screen and improves visibility, which can improve user comfort during extended operations.
Ductless fume hoods have factory-installed service fixtures available that are spaced appropriately in the cabinet work area to ensure ease of use for any number of laboratory operations.
Learn more about additional ergonomic design features in ductless fume hoods.
One of the major benefits of ductless fume hoods is their mobility and portability. Ductless fume hoods provide portable containment solutions which offer the same amount of protection as ducted fume hoods in the laboratory, but with flexibility in location.
Ductless fume hoods do not require additional ductwork or specialized utilities, so they can easily be moved from one location to another inside the laboratory. Some ductless hoods are even designed to be part of mobile laboratory setups or to provide containment in temporary locations at crime scenes.