Properly Selecting and Using a Cleanroom Vacuum

What you need to know about one of the most important pieces of equipment in your cleanroom.

We recently posted a comparison to help you choose between a central and portable vacuum system for your cleanroom. Once you decide which system is right for you, there are a few more things to know about picking out your vacuum.

Crucial Elements of the Equipment

The absolute first thing you must ensure is that your vacuum cleaner is HEPA-filtered. This is the only way to know that 99.97% of particles down to and including 0.3 microns are collected and retained.

Another critical piece of the filtration system is when the HEPA filter goes in. It should be installed after the motor to filter the exhaust stream. The commutator and carbon brushes in the motor generate dust; if the exhaust stream isn’t filtered, that dust will be released into the room.

You will also need a multi-stage, graduated filtration system. This uses a series of finer filters to trap and retain particles moving through the system. It will also protect the HEPA filters from blockage and excessive wear and tear.

The filters should be oversized to slow airflow and optimize the air-to-cloth ratio. The vacuum will be able to collect large volumes of debris over long periods of time with minimal maintenance this way.

The unit itself should be constructed of non-particle-generating materials. Stainless steel vacuums, for example, should have smooth hoses and attachments so personnel may quickly wipe down and decontaminate equipment.

Another important component of your selection process is the manufacturer. Select one that offers a complete line of vacuums that are specifically designed for cleanroom applications. These manufacturers will offer other essentials: FDA-approved hoses, cleanroom-packaged vacuums, explosion-proof vacuums, and wet/dry vacuums.

Keeping it Clean

Once you have the right unit(s) for your controlled environment, there are things you can do to maintain optimal cleanliness:

  • Educate your staff on proper use of the equipment as well as protocol for hygiene
  • Maintain your equipment with regular cleaning and checkups on all the parts
  • Develop a schedule and enforce it to ensure comprehensive vacuuming of the entire facility after each shift

Vacuums are a key piece of keeping a cleanroom clean and compliant. When it’s time for validation, certification, or expansion of your cleanroom, choose Gerbig Engineering Company. We have a solid reputation and understanding of the industry. Call us at 888-628-0056 or email

Important Considerations for Cleanroom Vacuums

There are advantages to both portable and central vacuum systems for a cleanroom. Weigh your options with these comparisons.

When looking at everything needed to clean a cleanroom, the initial removal of dust and particles comes before sanitation. In critical cleaning situations, vacuuming tends to be a more efficient method than swabs and cloths. Measurements taken in a cleanroom setting show that dusting systems using disposable cloths polluted the space twice as much as a HEPA filtered vacuum cleaner.  Vacuums both retain particles inside the machine and eliminate fiber particles left behind by various wipers.

The first question you need to consider when choosing a cleanroom vacuum is: central system, portable, or both? While experts will argue for each option, the best choice for you depends on your application. Here are the pros and cons of the two systems:


  • PRO: Personnel can effectively and easily clean their areas at the end of each shift. These vacuums are best for areas where human contamination is prevalent.
  • PRO: These vacuums can be designed for both wet and dry applications, whereas the central systems can only pick up dry materials.
  • PRO: These systems can reach places the central ones can’t, like overhead or remote areas.
  • CON: These units do occupy precious cleanroom space. Compact models are a popular choice for this reason.


  • PRO: The greatest benefit of these systems is that personnel are able to dispose of collected dirt outside of the cleanroom. This then poses no threat to the manufacturing process.
  • PRO: They free up floor space as they’re located outside of the cleanroom.
  • CON: If you expand your operation, the central system may not have the capabilities to support your new area.
  • CON: If a contaminant enters it, the entire system may be contaminated. This requires a costly sanitation process to fix it.

Many cleanrooms do need a vacuum to have both wet and dry capabilities, so if you’re leaning towards a central system, you’re probably truly looking at having both systems. Once you know which system you want, you can focus on what to look for in a vacuum. We will cover that in our next article.

If you need cleanroom validation, certification, or manufacturing, choose a company you trust. Our experts bring 30 years of experience to our superior service. Call us at 888-628-0056 or email

How to Swab Cleanroom Surfaces in a Reproducible Manner

Validation relies on meticulous and accurate testing. When swabbing for residue samples, follow this advice for reproducible results.

If you consider cleaning validation a three-step process, it will involve 1) cleaning/rinsing of necessary surfaces, 2) sampling any residues left behind after step 1, and 3) analyzing your samples. The greatest challenge in this 3-step process is ensuring that step two is carried out in a highly reproducible manner. If it isn’t, the analysis won’t truly represent the condition of the sampled surface.

To accomplish reproducibility, you want to focus on four things:

  • Thorough completion of step one
  • Use the proper swab
  • Wet the swab correctly
  • Swipe the area consistently

The first step above is rather obvious. If you can actually see particles on any surface, you need to clean it. The residues you’re testing are invisible to the naked eye. Moving on to the second area of focus, the best swab for sampling will be made from laundered polyester knit fabric. This material releases the fewest particles, has the highest recovery, and provides the lowest background when TOC measurements are employed.

With the right swab in hand, in order to sample, the swab needs to be moistened. If you merely saturate the swab head with high-quality water, excess liquid will spread residue over the surface rather than collect on the material. The swab should be damp but not saturated. After immersing the head into a container of high-quality water, simply press both sides of it against the inside of the container to release trapped air. Draw both swab head sides across the rim of the container to expel excess liquid.

Once properly moistened, you want to use a consistent swabbing pattern. The area you’re sampling will usually be 5cm by 5 cm. Then use the following pattern:

  • Swipe the first side of the swab horizontally ten times over the sampling area.
  • Flip the swab and swipe the other side ten times vertically over the area.
  • Deposit the swab into a collection vial.
  • Use the first side of a second swab to swipe the same area diagonally upwards ten times.
  • Flip the swab over and swipe diagonally downwards ten times.
  • Deposit the second swab into the same collection vial.

The figure below shows the swiping pattern. It is taken from the article “How To Succeed In The Search For Nothing: Effective Swabbing Techniques For Cleaning Validation” by Wendy Hollands, Howard Siegerman, Ph.D., Michael Strauss.


Proper swabbing techniques will ensure that you get accurate results. For other questions about validation or cleanroom certification, contact Gerbig Engineering Company. We have 30 years of experience delivering expert cleanroom services. Call 888-628-0056 or email today.

3 Tips on Testing for Fungal Control in Cleanrooms

There is a lot to consider when taking action to control fungus in a controlled environment. Make sure you know these three tips.

Recently, we posted about controlling fungus in cleanrooms.  This is a tricky subject because it depends on the form of fungus, the surface type, and environment specific to your controlled environment. We ended the series with suggestions on the kinds of test you should perform. Here is some additional information to help with that process.

Suspension tests:

It is worth noting that there are many published methods to determine fungal activity in suspension or carrier tests. You can find general test procedures to use for fungicidal activity testing in the BS EN methods (1650 and 13697) established by the European Committee for Standardization and the AOAC. However, these methods are specifically used by disinfectant manufacturers to register a product for sale. Therefore certain methods won’t be applicable or necessary to cleanroom disinfectants. Know that you can make reasonable modifications so long as they are scientifically sound.

Which fungus to test:

Wondering which fungus to use as a test microbe, like yeast or mold? Generally, you want to use fungal spore suspensions of both reference cultures and environmental isolates. Consider this example:

The AOAC fungicidal test uses Trichophyton mentagrophytes as a reference organism. This doesn’t present as great a challenge to the disinfectants as does A. niger, so it is rather misleading. It is also not as common in pharmaceutical, biotech, and medical device cleanrooms. Consequently, the procedure should include A. niger and C. albicans as reference cultures.

Your disinfectant effectiveness testing should also include the specific environmental isolates most frequently found in the facility.

A couple extra notes about preparing suspension tests:

Prepare yeast suspensions from yeast propagated on media that results in rapid growth and smooth colonies. Remember that mature mold cultures are more resistant to fungicides than are yeast cultures. Prepare molds for validation testing as conidia suspensions with hyphal fragments removed. The conidia presents the greatest disinfection challenges.

Ensure that your tests are carried out thoroughly and carefully. Document everything and make sure you are current on validation and certification. If you need your cleanroom validated or certified, contact Gerbig Engineering Company at 888-628-0056 or Our 30 years of experience make us experts who care about your business.

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