Laminar Flow Hood Cleaning

Our lab safety experts share their methods for a laminar flow hood cleaning. Plus some additional tips to keep you lab safe

With each piece of lab equipment, there are different steps you need to take to ensure you have a sterile and safe environment. We will discuss how to effectively perform laminar flow hood cleaning and give you a few other tips to ensure your lab is safe.

Start Up The Unit

The first thing you will want to do is start the unit. It is important to have the hood blowing for at least 30 minutes prior to beginning the cleaning process.

Suit Up And Get The Cleaning Equipment!

Before you begin the cleaning process, you are going to want to ensure you are wearing sterile clothing. Start by putting on the appropriate PPE. This generally involves wearing a gown with gloves, a mask, head covering, and shoe coverings.

Lab technician in a full body gown and mask reviewing a checklist

During this stage you will also want to grab laboratory grade cleaning wipes along with a 70% ethanol spray solution. (Soap and water should not be used and always use lint free cleanroom clothes)

Pre-Cleaning Important Facts To Know

Before you begin cleaning the unit, there are few important things you need to know.

HEPA Filters

HEPA filters are very delicate and require careful attention as to not be damage when cleaning the unit. Depending on how your unit is set up, you may have a metal shield over the HEPA filter which can be wiped down. Do not use excessive pressure when wiping this shield as you could damage the filter if too much pressure is applied. You also should never spray cleaning solution directly on the shield, instead spray the solution onto a wipe.

illustrated drawing of air and contaminants passing through a HEPA filter

In other units, you may not have a protective metal shield in front of the filter. Instead, it may be a metal grate where you can easily see the filter media. In this style of hood, you should not clean the HEPA filter surface.


You should use a clean wipe for each surface of the hood. This reduces the risk of contamination.

Start Cleaning

In the first stage of the cleaning process you will be using the laboratory grade cleaning wipes.

Start by cleaning the ceiling of the unit first for horizontal laminar flow hoods. (For vertical laminar flow hoods you will skip this step unless your HEPA filter on the ceiling has a protective shield.) Start in the back-left corner and clean from left to right with a long swiping motion. As you move from back to front, overlap each swipe by 25 to 50% to ensure all surfaces get cleaned.

Next clean the back wall if a HEPA shield is present. Work from top to bottom using the same swiping and overlapping you used on the ceiling of the unit. If a shield is not present, then you do not clean the HEPA surface.

Next work your way to the sides of the unit, start in the back corner. Clean from top to bottom and from back to front. Ensure you use a clean wipe for each surface.

Finally, it is time to clean the work surface. In a similar fashion as the ceiling cleaning, work from the back corner and wipe from right to left. Ensure a 25 to 50% overlap on each wipe and do this until you reach the front of the unit.

Sterilize The Unit

You will follow the same steps laid out above, this time using a lint free cloth and your 70% isopropyl alcohol solution. Always spray the alcohol onto the cloth and never directly onto the surfaces. Ensure a clean portion of the cloth or new cloth entirely are used for each of the surfaces you wipe down. And that’s it!

Be sure to dispose of all discarded materials in a biohazard waste-basket. If the unit has a UV Sterilizer, this can also be used to disinfect the hood.

Frequently Asked Questions

What Are The Different Classes Of Laminar Flow Hoods?

There are 3 different classes of laminar flow hoods.

  • Class I Laminar Flow Hoods – These hoods the simplest of the three classes. These hoods do a good job of protecting the user and outside environment but do not protect the work substances or cultures from contamination.
  • Class II Laminar Flow Hoods – These hoods are often used when hazardous material and fumes pose a risk to the user. These hoods also provide a sterile aseptic environment for the materials in the hood. Class II hoods are used in applications involving BSL-1, 2, and 3 materials.
  • Class III Laminar Flow Hoods – These offer the most protection. They provide the ultimate level of possible protection. These units are gas tight and are used in BSL-4 materials. This often includes pathogens and infectious substances.

What Laminar Flow Hood Services Does Balcon Perform?

  • Inflow Velocity Measurements
  • Down-Flow Velocity Measurements
  • HEPA Filter Integrity Testing
  • Non-Viable Particle Counting
  • Microbial Air Testing
  • Microbial Surface Testing
  • Temperature and Humidity Uniformity
  • Smoke Pattern Testing
  • Alarm Calibration
  • Site Installation