Conventional, Modular Hardwall, and Modular Softwall Structural Considerations
Cleanroom structural systems, depending on the cleanroom cleanliness classification and process, can be of conventional, modular hardwall, or modular softwall designs. Robust systems should offer smooth, easily maintainable, wall, ceiling, and flooring finishes capable of withstanding impact, abrasions, uv lighting, and chemical cleaning agents. Concealed systems such as structural steel support systems for suspending utility chases, ceiling grid systems, HEPA filtration modules and cleanroom lighting fixtures must be of adequate design to manage excessive loads over clear span distances.
When considering the construction of a cleanroom environmental enclosure system, cleanroom cleanliness classification, process, and other factors should be taken into consideration when selecting the appropriate method and materials of construction.
Cleanroom Wall Systems can be of conventional or modular type construction. Each system requires specialized design and engineering to meet process, regulatory standards, and local code compliance. Several design and engineering criteria's must be taken into account when deciding which materials and system to utilize for cleanroom wall construction. Cleanliness classification, cleanroom processes, electrostatic management, microbial bioburden control can dictate materials, finishes, and construction methods
Cleanroom Ceiling Systems create a sealed membrane ceiling system to prevent loss of pressurization, particulate intrusion, and bioburden or cross contamination issues. Ceiling systems can be of panelized construction or suspended grid type systems. Cleanroom ceiling system selection will need to take into account fire ratings, filtration systems, lighting systems, and maintenance requirements for proper materials selection and engineering.
Cleanroom Flooring Systems may be vinyl tile, seamless vinyl sheeting, broadcast epoxy resin or of a raised surface system depending on process, utility, and bioburden concerns.
Cleanroom Entry / Egress Systems such as air locks, air showers, misting rooms, require fully gasketed closures and interlocking devices to prevent pressure loss, particulate intrusion, or cross contamination from affecting the cleanroom environment and process. Specialty hardware may be required to prevent unauthorized access, microbial bioburden control, and to meet regulatory requirements for performance of the cleanroom process.
Cleanroom Window Systems may require specialized trim and mounting systems to keep glazing systems flush with the cleanroom wall surface to prevent areas where particulate build up may occur. They can also be required to meet the same fire rating required by the wall systems. Flush window designs are available in single pane, flush one side or dual pane, flush on both sides, designs for perimeter and intermediate wall systems.
Cleanroom Pass Through Devices allow materials and product to pass through wall systems while preventing pressure loss and cross contamination. Pass through devices can have HEPA filters, mechanical or electrical interlocks, and are required to meet the fire rating of the wall systems. They are available in high pressure laminates(HPL), polypropylene, acrylic, and stainless steel designs.
Cleanroom Structural Steel Support systems require more robust design and engineering to accommodate increased loading due to the size and weight of utility systems, process equipment, and ceiling systems.
Cleanroom Building Code Compliance may be dictated by existing building design, cleanroom processes, and regional building code standards. Cleanroom process, chemicals, hazardous exhaust, and waste materials require specialized systems to assure environmental compliance and personnel safety.
Cleanroom Regulatory Agency Requirements may dictate the use of approved materials and systems to meet insurance, process, or NFPA requirements.
Cleanroom Fire Ratings may be required to meet U.L., NFPA 318, FM Global, and local building code standards. Fire ratings directly dictate materials, finishes, and systems utilized for cleanroom wall and ceiling construction
Window Framing Systems should be of a flush style design with the glazing flush to the interior cleanroom wall surface. In walls separating two cleanroom rated areas windows should be double glazed to be flush on both sides. Cleanroom windows are required to match the fire rating of the wall system. This can limit size and number allowed in wall systems required to be fire rated.
Systems Flexibility should be inherent in modular hard wall or soft wall prefabricated systems. Panels should utilize non progressive connecting methods and be interchangeable with like sized panels. Changes in process, process flow, and manufacturing capacity make changes inevitable. Cleanroom renovations require clean build protocols to avoid contamination to existing processes.
Systems Durability should be commercial grade or above as cleanroom environments can operate 24/7 for years at a time. Cleanroom wall systems, door systems, ceiling systems and flooring systems, must be able to contend with chemical cleaning agents, exposure to uv, impact and bioburden limits. Downtime to maintain and refinish wall, door, and window systems can be costly and time consuming.
Cleanroom Sustainability can be greatly increased with correct construction methods and materials. Low VOC Outgassing, reusability of cleanroom components during renovations, and durability of finishes should be directly addressed when specifying cleanroom construction materials and methods.
In summary cleanroom wall systems and enclosures should be constructed from low VOC materials with low porosity commercial grade finishes to resist impact or abrasion. They should be constructed as durable as the budget allows to avoid downtime and maintenance. Materials should meet specifications of and be approved by the regulatory agencies involved in the construction and operational process.