In comparison to ducted fume hoods, ductless fume hoods are highly technically advanced. Many safety factors, monitors, alarms and engineering improvements have been made to ensure that ductless technology provides the same safety level or better than any ducted fume hood on the market. For example, the addition of electrostatic pre-filters accessible from within the ductless fume hood, enhances the safety for operators and the longevity of the main carbon filters.
Due to the design of the air circulation system, some manufacturers have also created high pressure filter clamping mechanisms to ensure proper filter seal and prevent bypass leakage. The design of the filter chamber also prevents contaminated air from contacting any internal cabinet mechanisms, further enhancing operator safety and contamination filtration.
Ductless fume hoods are often equipped with advanced monitoring systems, airflow monitors and filter condition monitors to ensure the utmost in safety enhancements. Audible alarms, gas stage monitors and visible filter saturation alarms can all be set to meet current standards and TLV readings for various chemicals. Real-time airflow and filter monitoring are also available on a number of ductless models on the market today.
Additional safety factors include construction and fire safety features.
Fume hoods are designed to protect operators and equipment from a variety of fume and particulate contaminants, many of which are volatile and can be highly combustible. Ducted and ductless fume hoods therefore need to be capable of withstanding or guarding against potential flash fires.
Many scientific disciplines and standard operating procedures involve the use of potential ignition sources, including hot plates and other electrical equipment. High quality fume hoods should not only protect the users from potential chemical contamination but should also include measures to protect against fire.
A variety of features can be added to enhance the fire performance of fume hoods, including steel substructures, fire suppression systems and fire resistant filters. Fire testing can indicate how ducted and ductless fume hoods will perform in the event of a fire, with the most important factors being whether the hood will continue to maintain structural integrity and protect operators and surrounding areas.