Hood Positioning in a Cleanroom

You have spent hours researching which compounding hoods meet the needs of your pharmacy and your budget. Your architect and engineer have made sure the air handlers on the roof can provide the volumes you need. All you need to do is figure out where to place them in your cleanroom. Unfortunately, this is not as easy as it seems.

There are several variables to consider:

  1. Regulations/Requirements
  2. Ease of cleaning
  3. Worksurface height


While there are no specific USP rules about hood location, several other requirements can impact placement:

  • The need to supply a 3 ft square area by the door for de-gowning on exit from a Hazardous Compounding Room.
  • The ability for the Pharmacy Manager to easily observe the technician during compounding.
  • The best practice of keeping cleaning supplies (such as mops and cleaning wands) at least 3 feet away from hood(s).
  • Whether you plan to mount a computer for the technician to the hood or the wall.
  • Each hood manufacturer may also have minimum distances from walls that they require to allow for proper functioning.

Hoods cannot be placed directly under a HEPA filter, as it will disrupt the airflow in the room.

Ease of Cleaning

Cleanrooms must, of course, be clean. Putting together a plan to clean every inch of your cleanroom is a necessary action. What will you use to clean behind the hoods? How much clearance must there be to allow for proper cleaning?

We generally recommend at least 12 inches of space between the back wall and the hood, and at least 18 inches of space between the side walls and the hood. One thing to consider is HOW your staff will clean. Will they be cleaning by hand or using some sort of wand? If your hood is in an alcove or niche, will your staff be able to reach all its surfaces?

Worksurface Height

This decision may be made for you depending on your hood manufacturer. If not, there are variables that may limit your options. Hazardous compounding hoods are often quite tall; you may be limited to sitting height by the height of the ceiling. IV hoods tend to be shorter, allowing either sitting or standing height. Some manufacturers also offer variable height hoods that use electric lifts.

Once you have taken all these variables into account, there is still the fact that your options may be limited by above-ceiling conditions. Architectural structures such as beams, pipes, and ducting may cause issues. Working out your needs early-on in a project and communicating them to your architect and engineer will allow you to determine the best possible placement for each hood.


Updated on October 11, 2021 to reflect hood position best practices.