Cleanrooms may be any controlled environment that regulates particle size and the movement of air in and out of the space. Softwall Cleanrooms are great for smaller applications, relatively easy to install, maintain and move around within a larger space. Typically constructed with steel or aluminum frames they have clear vinyl curtain strips or panels around the perimeter and are pressurized via fan filter modules. Optics Lab Modular Cleanrooms are more commonly used for larger cleanrooms inside a manufacturing space. As the name implies, these cleanrooms are flexible to long term expansion and moving large equipment through the removable wall panels. Modular cleanrooms also have the flexibility of utilizing a once thru or recirculating HVAC design. In addition, the variety of wall panel construction and surface material allows these systems to be practical in virtually any environment.
Built-in-Place refers to the larger manufacturing cleanroom environments that are an integral part of the building structure. Most applicable for new construction, these rooms can be built to fit any environment, handle any heat load, classification and incorporate both modular and softwall features within the space. Conversion of smaller office-to-cleanroom renovations incorporate this design as well.
The ISO (International Organization for Standardization) has recently established a guide for controlled environments.
Many people find the older Federal Standard 209 chart easier to understand and apply.
Cleanrooms come in all shapes and sizes and as such a variety of materials is often necessary. Most of the time the wall, ceiling, and floor materials are determined by economics, however, keep in mind that certain process chemicals and gases, cleaning agents and acids react differently to certain substrates. Consult your MSDS for more specific information.
Flooring options include: solid heat seam-welded vinyl, self-leveling epoxy, tile floors and conductive raised access flooring. Wall Materials can be aluminum, vinyl hardboard, painted steel, stainless steel, PVC, and epoxy painted sheetrock.
Grid Systems may be PVC or anodized aluminum, range from 1", 1.5" or 2" wide. The seal may be a gasket of low-off gassing cellular urethane, low VOC material, neoprene, polyethylene, antibacterial, or fire retardant. 2" wet-seal grid systems are also available used knife edge ceiling tiles and filters.
Ceiling Tiles may be vinyl hardboard with sealed edges, aluminum, steel or PVC. Lighting may be provided using 2' x 4' troffers, tear drop light fixtures, integrated flow thru light troffers, yellow lenses and a variety of bulbs. Filters are either HEPA or ULPA, efficiencies ranging from 99.97% efficient at 0.5 microns to 99.99995% at 0.12 microns. Depending on the mechanical design, Terminal diffusers or Fan Filter Modules may be used. Other options include gaskets downstream, room-side replaceable filter housing, and size.
Ionization is used for critical environments where static charge is a concern, emitting positive and negative ions into the space neutralizing the surface area.
Systems range from complete room ionization using ceiling emitters to more localized blowers and fans. Installation and certification are included on all room ionization packages.
Particle Counting Systems may be as simple as a portable particle counter to larger machines with remote sensors monitoring particle size, matter, and frequency. Most sytems are programmable or come with computer software that can create graphes and charts for display.
Cleanroom Certification is assurance that your cleanroom meets spec and provides your customers with confidence of the manufacturing environment. Air Showers are used to gain entry into cleanrooms blowing filtered air on and
around the person to remove any surface contaminants before entering the clean space.
Pass Thrus are small airtight enclosures in the wall used to pass sensitive material from one room to another without being contaminated.
For computers and associated equipment, please make sure the cleanroom manager knows you plan
to bring these items in and if you require LAN access from within the cleanroom. Before entering any
part of the cleanroom, pre-clean the items with IPA and fiber free wipes. Detailed cleaning
instructions will follow this general guideline.
For equipment such as computers, keyboards etc, vacuum clean using a general purpose vacuum
cleaner. Particular attention should be paid to the ventilation ports. This pre clean should be done
external to the cleanroom and anteroom and items should be covered with clean bagging material,
but not of cleanroom quality. As a guide, notebook computers are preferred to desktop computers
(although this is not always practical) not only due to size but also from a cleanliness aspect. Clean
all equipment at an external location to the cleanroom. This equipment can then be bagged to
Small metallic items (screws, nuts, washers) and non metallic items that are safe to use with
solvents must be cleaned using the ultra sonic cleaner located in the chemical lab. Upon entering the
cleanroom anteroom remove from packaging and visually inspect for any obvious signs of
contamination that may have been missed and re-clean if necessary. The best way to visually
inspect any item is to view the item surface at a five degree angle with good background lighting
When cleaning items using wipes provided in the anteroom do the following:
Fold the wiper in half and then fold in half again.
If the person who performs the cleaning operation then goes into the cleanroom, a new pair of
cleanroom gloves must be fitted. The clean item can then be taken into the cleanroom and any
necessary final cleanup can be done within the cleanroom as described above using wipers and IPA
Cleaning and decontaminating cleanrooms are critical tasks to ensure both the integrity of the cleanroom itself and the products made within it. The cleaning activities are therefore tightly controlled, with cleaning products, cleaning methods and cleaning frequencies carefully spelled out in detailed standard operating procedures. Not all cleanrooms are cleaned the same way. The specific cleaning products, methods and frequencies are carefully selected based on the cleanroom class, the contaminants of major concern, the products manufactured and the materials of construction within the room itself. As an example, in ISO Class 3 cleanrooms used to manufacture electronic devices minimization of particle levels is critical, while in ISO Class 5 sterile cleanrooms used to manufacture pharmaceutical or biotechnology products minimization of contamination from bacteria and other viables is paramount.
We invite GSFCC blog readers to contribute articles on this important topic.
Following are references that can be consulted for additional information: