The Differences in Electrostatic Discharge Control Packaging for Cleanrooms

integrated_workstations.jpgAnyone who works in a cleanroom knows the importance of controlling electrostatic discharge (ESD.) He or she also knows how easily motion and activity can create the unwanted static. We’ve written some articles on controlling ESD, but we have not covered the different kinds of packaging that is available.

Surface resistivity units of ohms per square are used to measure ESD protective totes and packaging. You’ll find these materials categorized in one of three ways:

  • Conductive Surface Resistivity (CSR) – by compounding carbon particles material (CPM) into plastic resin, surface resistivity is permanently changed. The surface transforms from an electrical insulator to an electrical conductor. The charge bleeds off a grounded tote; a covered tote also provides “an electrically continuous conductive enclosure that provides electrostatic protection.” (“Controlling Electrostatic Discharge in Cleanroom Packaging,” Michael Mills, Kathy Mills, Justin Mills, Laura Clark;


  • Static Dissipative Surface Resistivity (SDSR) – this is also achieved by compounding CPM into plastic resin. When the result is SDSR, the rate of static discharge is slower than conductive material. SDSR works when it makes contact with ESD-sensitive components.


  • Antistatic Surface Resistivity (ASR) – this material resists high amounts of charge accumulation and does not need to be grounded. One downside to using this kind of material is that the additives used to create resistivity can migrate to the surface and evaporate.


Knowing these three kinds of properties, let’s look at the actual packages and containers you can choose from:

  • Corrugated Paper and Paperboard – these packages are coated with carbon black, foils, or other materials to provide ESD protection. It is a low cost option, but the dust and other debris from the packaging can damage components. They come in a number of standard sizes.


  • Molded Plastic – these totes are available in all three kinds of anti-static material. They are durable and reusable, but if you need to customize the size, it does become a costly option.


  • Corrugated Plastic – these totes come in CSR and ASR, ranging in thickness from 2 – 6 mm. The plastic is a more costly option than paper, but it’s far more durable. If you need the container to last a long time, opt for CSR as ASR is not permanent.


The final decision, timeframe, and cost of your tote will depend on many things. You’ll need to determine the use of the container (everything form tracking to stacking to fitting onto shelves.) You can ask for prototypes or samples to make sure your products fit your needs. You also need to remember to make sure that the final package fits onto your storage unit. With the right container for your process, you can effectively continue to control ESD in your cleanroom.

Gerbig Engineering Company performs certification and validation for cleanrooms. We also manufacture AireCell Cleanrooms. For questions about cleanroom processes or requirements, contact us at 888-628-0056 or

*For a more detailed explanation of ESD packaging, read this article

Differences in Water: Cleaning your Cleanroom

class_10_storage_unit.jpgWater is one of the most widely-used ingredients in any cleaning solution. With the proper additives, water is an effective cleanser. However, in critical manufacturing, it is important to know that all water is different (even tap water in two different locations.) The quality of water directly impacts the quality of your product. Therefore, you need to choose the right kind of water for your cleaning application. Here is a breakdown of the different types of water.

Tap Water: There are many instances when using tap water is safe. Know that water does absorb minerals from the ground and gases from the air, so there is no such thing as pure water. Tap water has an assortment of minerals in it depending on its location, and it also varies from season to season.

When you find water with higher levels of dissolved minerals (calcium, magnesium), the water is hard. If you have hard water at home, you know from looking at your dishes, sink, and tub that it leaves residue behind. This residue is difficult to clean. Additionally, hard water interferes with soap’s effectiveness.

If you have a water softener at home, you are also familiar with soft water. The water softening process relies on ion exchange. While it has lower concentrations of the hard minerals, the water now contains sodium. As for cleaning, sodium does not interfere as much with soaps, but the water itself has the same ionic content.

Deionized Water: That brings us to the removal of ionic properties. The ion exchange process to deionize water removes both cations (positively charged ions like calcium and sodium) and anions (negatively charged ions like chlorine.) As a result, the conductivity decreases – measuring this is how most deionized water is tested for effectiveness. Remember, though, the deionizing process does not remove non-ionic materials.

Reverse Osmosis: To understand the process, imagine that a semi-permeable membrane separates one side of  “pure” water with another side that contains dissolved material.  Normally, water would pass back and forth until the concentration on both sides of the membrane is equal. In reverse osmosis, rather than creating an isotonic concentration of water, pressure is used to reverse the process. The dissolved material side is forced to move to the purer side. This filtration process does separate most dissolved material, but not all.

Distilled Water: Most ionic and inorganic properties have a lower vapor pressure than water. As such, evaporating those materials into a separate container effectively removes them. However, organic solvents that have a substantial vapor pressure will still be in the distillate.

Distillation and reverse osmosis are most commonly used to produce Water for Injection (WFI). This WFI meets USP specifications that limit organic, inorganic, and biological impurities.

UV light is also sometimes used to kill bacteria, but the dead bacteria is not separated from the water.

It is easy to compromise the purity of any water, so choosing the right one will depend on your needs. You have to decide whether cleaning your facility is a question of ionic materials, dissolved materials, organic materials, and anything else that is left behind in any type of water you may use

Gerbig Engineering Company performs certification and validation for cleanrooms. We also manufacture AireCell Cleanrooms. For questions about cleanroom processes or requirements, contact us at 888-628-0056 or

* Information obtained from the Controlled Environments article “Perfect Water,” by Barbara Kanegsberg and Ed Kanegsberg,

Checklist of Considerations for Pharma Cleanroom Design: Part Two

IMG_2295Last week, we began summarizing the main points of Tim Sandle, PhD’s article in Controlled Environments. His article provides a close look at what needs to be considered when building a pharmaceutical cleanroom. At the end, we provided a link to a full article on validation master plans, as one requires full comprehension of this step. Here we will conclude our checklist.

With your concepts identified and a master validation plan in hand, your next step is cleanroom design. The design specification is a set of documents with your drawings and explanatory notes. You’ll need to check your final specification against industry standards.

Fortunately, the design process can be assisted electronically, usually with computational fluid dynamics (CFD). Computers are used to calculate all the factors within the cleanroom, thereby enabling cleanrooms and its equipment to be accurately designed. Regardless of whether you use CFD, Sandle recommends that your design include:

  • The basic design using working drawings
  • Design specification
  • Start-up
  • Testing
  • Commissioning
  • Operation
  • Construction, including installation (drawn), execution, field supervision, and executive drawings.


The construction process does also require additional detailed documentation, including:

  • Specs for control equipment
  • Process flow charts
  • Personnel (qualification, how many)
  • Cleanroom or separation concept
  • Utilities
  • Safety requirements
  • Waste disposal


Sandle points out that risk assessment is a regulatory expectation that is somewhat new. To help you with this, he states, “In applying risk assessment to the design process, the most important guidance document is ICH Q9.4 ICH Q9 was adopted as part of EU GMP in 2008 and by the FDA in 2010.”

At this point you have:

  • Created your cleanroom specification
  • Ensured that everything in the cleanroom is easy to clean and can withstand the cleaning process
  • Prepared a master validation plan
  • Created your design specifications
  • Completed construction


Once construction is complete, you will have an initial qualification followed by a performance qualification (PQ).  The most important PQ test will be that which measures particle count. This tells you the level of contamination, proving that your cleanroom meets the criteria for its specific class.

Other PQ protocols test:

  • Temperature
  • Humidity
  • Air pressure
  • Filter system leakage
  • Airflow direction
  • Recovery


Once your cleanroom is operational, you will need to undergo ongoing compliance. You will further be tested every six months – 1 year (depending on your class of cleanroom.) As a new facility, each phase will be tested. However, once established, your facility will either be tested “at rest” or “in operation” with these things in mind:

  • Class of air cleanliness
  • The pressure differences between rooms
  • Air velocity/air flow rate
  • HEPA filter leak test


As mentioned last week, every step of your plan should be carried out thoroughly and by properly credentialed individuals. Gerbig Engineering Company manufactures Airecell cleanrooms. We also perform cleanroom certification and validation. For questions about cleanrooms, validation, or certification, contact us at 888-628-0056 or We would be happy to help you.


Checklist of Considerations for Pharma Cleanroom Design: Part One

medical device cleanroomContamination control in a cleanroom is reliant upon a number of factors. Pharmaceutical grade cleanrooms have a few more factors than some other controlled environments. There are a number of standard considerations in pharma cleanroom design to control contamination caused by the combination of airflow, sources of heat, and any objects present.


Tim Sandle, PhD, wrote a thorough description of these considerations in “Modern Approaches to Pharma Cleanroom Design” for We have put together his main points to stand as a checklist.


The first step in designing your cleanroom is to create a specification. Here is what it needs to represent:


  • The defined area of the clean space
  • The required cleanliness level/class
  • The rate of optimal air change (no less than 20 hourly air changes) and the rate of the supply airflow
  • Requirements for positive pressure differentials
  • Any mini environments to add to air cleanliness, like localized unidirectional airflow or isolators
  • Optimal ceiling coverage for air filters. Sandle says, “With HEPA filters, the design should seek to include: HEPA filters with differential pressures (P); adequate space for low pressure drop air flow; low face velocity; fan design; motor efficiency; variable speed fans.”
  • Minimized pressure drop/air flow resistance
  • Appropriate size and minimal length of ductwork
  • Optimal pressurization
  • Savings in energy consumption – reducing the airflow when room is unoccupied
  • Efficient use of components
  • Electrical systems that power the air systems


Pharmaceutical cleanrooms need to be especially easy to clean and disinfect. In regards to your cleanroom construction, ensure that it has:


  • A smooth finish that is easy to clean
  • A final coating that is resistant to detergents and disinfectants you will need to use regularly
  • Cleanable surfaces – you should not have any recesses that you are unable to clean
  • Minimized amounts of projecting ledges
  • As few electrical sockets as possible
  • Appropriately contained (boxed in) pipes and conduits


The next step to prepare for is your validation master plan. Certifying and validating your cleanroom are extremely important.  Rather than summarize Sandle’s article, we recommend this full article by Jan Eudy. As a company that performs certification and validation, we at Gerbig Engineering Company can also answer questions you have regarding these processes.


In our next post, we will cover the remaining checklist points. These include design, risk assessment, qualification, and ongoing compliance. Use sufficient time and resources to get everything in order before you build. It will save you valuable time and money in the future.


For questions about cleanrooms, validation, or certification, contact us at 888-628-0056 or


USP 797 Compliance: Creating a Cleaning SOP

certification_testing_mainIf you’re maintaining a USP 797 compliant cleanroom, you’re required to have written cleaning SOPs and cleaning logs. Your SOP should include when to clean, how to clean, and what to clean with. Here are some guidelines on these categories.

How Often?

Surfaces of sterile compounding areas need to be cleaned with the most frequency. In’s article, “Cleaning Protocols for USP 797 Compliance,” Karen Bonnell writes, “It is required that the surfaces of BSCs, CAIs, CACIs, and LAFWs be cleaned and disinfected at the beginning of each shift, before each batch of product is compounded, not longer than 30 minutes following the previous surface disinfection when ongoing compounding activities are occurring, after spills, and when surface contamination is known or suspected.”

Daily cleaning and disinfecting duties include: counters, work surfaces, and floors (in all areas.) Be sure to only mop when there is no compounding in progress.

Monthly cleaning (at minimum) includes all other surfaces, ceilings, walls, shelving, and carts. These processes should also occur when there is no compounding in progress.

How to Clean

Cross-contamination is a concern with cleaning the wrong way, so it is best to clean from top to bottom, dry to wet, and from cleanest to dirtiest. Bonnell suggests: “In a monthly cleaning, the order would be: ceilings; walls and windows; exteriors of process equipment and cabinets; countertops and other horizontal surfaces; and at last, floors.”

When using wipers (see reachable surfaces), Bonnell explains, “Wipers should be folded so that the entire surface of the wiper can be used. Typically wipers are quarter folded, and then refolded after every wipe of the surface, to contain and remove the contamination. In this manner, there are eight different surfaces of the wiper exposed and able to be used for wiping. Wiping should be done in overlapping linear strokes from clean to dirty or dry to wet. After all eight surfaces have been used, the wiper (and its captured contamination) should be discarded in an appropriate container.”

When cleaning the floors, remember that the corners furthest away from the entry doors are the cleanest, so start there and move towards the higher-trafficked areas. Mop in overlapping linear strokes.

What to Clean With

Your choice of cleaning equipment depends on what you are cleaning. Here is a rundown of what to use:

  • For reachable surfaces: Use low-linting wipers and solutions that are appropriate for your environment. Check which materials and solvents are approved for your particular class of cleanroom. Wipers should not be so wet that they are dripping with solution.


  •  Floors: Floor mops may be flat using a bucketless system, or made of tubular knitted yarn and used with 2-3 buckets. It is necessary to use more than one rinse bucket to ensure that dirt does not go back on the floor. For bucketless systems, mops are either pre-wetted or sprayed with a solution.


  • Difficult to reach surfaces: Mop-like tools are made for those surfaces out of your reach. They are isolator cleaning tools, and you use them with replaceable mop covers.


  • Tight areas: For vents, junctions, dimples, and the like, use a swab wetted with a cleaning solution, IPA, or sterile water to clean these tight spaces.


Training is just as important as implementing your SOP. You will want to not only train and test personnel before they begin work in the cleanroom; you also want to schedule regular re-trainings. Make sure your written SOP is always available to personnel. Finally, using charts, checklists, and training posters will help operators retain the information.


Gerbig Engineering Company performs certification and validation of cleanrooms. We also build quality Airecell cleanrooms. For questions about equipment, processes, or construction, contact us at 888-628-0056 or


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