Safe Uses For Safe, Appropriate Filtered, Self-Contained Enclosures
•Report: Safe Uses For Safe, Appropriate Filtered, Self-Contained Enclosures
The need for alternatives to fume hoods Until the past decade, laboratory directors and safety officers have had only one option for protecting workers in the laboratory from exposure to chemical fumes and vapors: exhaust contaminants using a fume hood connected to ductwork leading from the hood to the outside of the building.
In most uncontrolled situations, fume hoods remain the equipment of choice for ventilating hazardous airborne materials from the laboratory. But there are situations when installing a ducted hood is impractical or has undesirable consequences because of any of the following:
- Flexibility in placement of the ducted fume hood is limited. Laboratories located in the center or bottom of a several story building may not have a ducting option.
- Some laboratories are "air-starved" and the make-up air available is insufficient to accommodate a ducted fume hood.
- Loss of conditioned air results in a less energy efficient heating and cooling system, increasing costs.
- The initial expense for ductwork and installation is significant.
- Portability is essential.
The ideal solution: a non-ventilated fume hood
Lab designers searched for years for alternatives to ducted fume hoods. The solution appeared to be
small, benchtop hoods which did not require ducting to the outside. Instead, they worked on the
principle that fumes released within the hood would be filtered and exhausted through the hood,
returning clean, breathable air to the laboratory. In the 1980's various models of "ductless" hoods
came onto the market.
The advantages were immediately obvious and attractive to laboratory designers and managers:
- Much greater flexibility and many more options exist for placement location.
- Since air is recirculated to the laboratory, negative pressure is not created in "air-starved" laboratories.
- Operation is more energy efficient because no conditioned air is lost.
- Installation is simpler and less expensive.
- Portability is achieved.
•Report: Safe Uses For Safe, Appropriate Filtered, Self-Contained Enclosures