Lab equipment comes in many configurations to accommodate the range of chemicals and procedures that various labs engage in. Because of the complexity, it isn’t always easy to choose the correct equipment for your application. This analysis will help you determine whether a portable/ductless fume hood is the right choice for you.
What is a Portable Fume Hood?
A portable/ductless fume hood is also called a recirculating range hood, because it recirculates the air in your lab after passing it through a filter. They are self-contained laboratory enclosures that operate by passing a continuous flow of air across the work surface, drawing it through the filter to remove impurities, particles and chemical fumes. Unlike ducted fume hoods, portable/ductless fume hoods are not connected to the HVAC system in your building. They recycle the clean air back into your lab, rather than venting air outside as ducted hoods do.
Applications of Portable Fume Hoods
Portable/ductless fume hoods work well in light to medium duty labs that regularly use ten or fewer chemicals, and chemicals in small volumes of 500 mls or less. They work best in labs with experienced and well-trained lab personnel and in labs where it is not possible to vent outdoors. Total daily contaminant exposure per employee should not exceed two or three hours.
Benefits of a Portable Fume Hood
A portable/ductless fume hood can provide many benefits when compared to ducted fume hoods.
- Movable - Most ductless fume hoods are portable, so they can be shared among various projects at different times of the day or on different days of the week. Many portable/ductless fume hoods are on wheels, making it easy to position them when and where needed to roll them out of the way when they are not in service. This portability is impossible with ducted fume hoods, which are permanently connected to the building’s HVAC system.
- Save energy - Since a portable/ductless fume hood only uses energy when it’s in use, it may save energy over a ducted fume hood, which often runs continuously. Ducted fume hoods also need to push air over longer distances, which also consumes energy.
- Less expensive - The initial cost of a portable/ductless fume hood is almost always less than the cost of a ducted unit. In addition to the acquisition costs, ducted units have the added expense of the connection to the building HVAC system. The day to day operational cost of a portable/ductless fume hood is often lower than ducted hoods, since they have smaller motors and fans that typically only run when the unit is in use.
- Easy to install - A portable/ductless fume hood is often ready to go immediately after delivery. Workers simply insert the appropriate filter, roll it to the workstation and plug it in. Contrast this with ducted fume hoods which require more complex connections and may require licenses, permits and approvals before operating for the first time. Building engineers may require training to ensure proper maintenance and operations of ducted fume hoods, while portable/ductless fume hoods are easily maintained by the lab workers.
Drawbacks of Portable Fume Hoods
A portable/ductless fume hood may not be the best choice under certain conditions. If the chemicals in the lab are not easily removed by charcoal or other readily available filters, the hood will not be effective.
They may not operate well under extreme heat conditions or with a high chemical load. They are not a good choice for labs with students or inexperienced personnel.
In addition, the filter in a portable/ductless fume hood must be changed at regular intervals. You must rely on lab personnel to perform this task as required, and the cost of frequent filter changes may over time offset the initial low acquisition costs. Some chemicals cannot be adequately controlled with available filters.
Should You Invest in a Portable Fume Hood for Your Lab?
A portable/ductless fume hood may be the right choice for your lab. Before moving forward, you should talk to an experienced fume hood provider about your application. A fume hood expert can analyze your lab and work within your budget to help you make the right decision to ensure the safety of your lab personnel and the environment.
