walk-in fume hoods

It is very common to find walk-in fume hoods in a laboratory.  The fume hood is a piece of equipment that works as a ventilation system to remove vapors, dust, fumes, gasses, and fine mists from the air.  Walk-in fume hoods can also act as a physical barrier between chemical reactions in the labs and can protect the user from spills, reactions, fires, and exposure to dangerous gases.  The majority of fume hoods are box shaped and have a moveable window.  Laboratory experiments are then conducted within the hood to ensure dangerous chemicals and fumes are properly vented.

There are several key components to walk-in fume hoods that contribute to the functionality of the hood and the intended uses in the laboratory.  Below, we have detailed a few of the more specific parts to the fume hood.

Baffles – These are the moving parts at the back of the hood that are used to create slots and keep air flow moving uniformly across the hood opening.  The baffles eliminate any dead spots in air flow and help to optimize the efficiency of capturing dangerous fumes.

Sash – The sash is the door part of the walk in fume hood.  The sash can be adjusted to control the amount of airflow through the hood.  Each hood has an optimal sash setting that allows for the maximum amount of exhaust.  While the sash can be moved when working on an experiment, the sash should always be returned to the ideal setting as the hood is running.  There are three main types of sashes that can be found on fume hoods.

  • Vertical – This is a vertical sash that provides the most access to the area inside the fume hood.  This is typically the most common found.
  • Horizontal – Horizontal sashes provide the most access to the top of the hood but not the whole width.  The one added bonus of the horizontal sash is that it can also be used as a barrier to protect the person working in the lab.
  • Combination – This type of sash is a combination of both vertical and horizontal and has the advantages of both types.

Airfoil – The airfoil is found at the bottom of the hood and along the edge of the sides and helps to streamline the airflow to the hood.  The airfoil helps to eliminate any turbulence and keeps the airflow consistent and uniform while maximizing efficacy.  Without the airfoil, small eddies and pockets of turbulence can form and force the fume hood to not run at its maximum potential.

Exhaust plenum – Allows the airflow to be evenly distributed across the face of the hood.  This can become easily jammed if a paper towel or similar object gets mistakenly sucked into it.