Ducted fume cupboards

Ducted fume hoods are commonly found in industry and in large university research establishments. There is a wide choice of ducted fume cabinets available, but they all operate under the same basic principle – contaminated air is taken out of the workplace and expelled into the atmosphere via a fitted duct.

(The alternative to a ducted fume cabinet is a ductless or re circulating fume cabinet.)

Constant volume ducted fume hoods

These types of fume cabinets expel a constant volume of air into the atmosphere. However, a six foot constant volume fume hood uses as much energy as three average homes. Therefore the models that reduce the volume of air expelled are more energy efficient.

Variable volume ducted fume hoods

To improve the energy efficiency (and improve laboratory ventilation costs), fume cabinets with variable air volume systems can be used. These reduce the volume of the air expelled as the fume hood sash is closed. These models often come with an automatic sash closing mechanism, which will close the fume cupboard sash when the worker leaves the hood. This means that the hoods only expel maximum air when the hood is being used.

Position of fume cabinet ducting

The location of the ducting is important with a fume cabinet. It should not be positioned so that the discharge outlet is positioned near windows, air supply systems, or near where the public have access.

Advantages of constant volume ducted fume hoods

The fumes from chemicals are completely removed from the workplace.
They require little maintenance.
The fan is located some distance from the researcher, so there is little noise.

Disadvantages of constant volume ducted fume hoods

They require ugly ductwork to remove fumes.
Heated air is removed from the environment, so they are no energy efficient.
Fumes are released into the atmosphere untreated.

Fume cupboards

FUME CUPBOARDS