Cleanroom Design Considerations

Cleanroom Design Standards
For many companies and organizations, deciding what class cleanroom they need to adhere to is easy - it is specified by a client, government organization or other regulatory entity.  For others, the choice can be difficult - so an understanding for how cleanrooms are classified can be very helpful.  To assist with this, we turn to the primary authority for cleanroom classifications - the International Organization for Standardization or ISO.  They have classifications that range from ultra-clean ISO 1 cleanrooms to ISO 9 cleanrooms that strive to achieve ordinary room air within a dirtier environment.

Airflow Design Patterns
Another design consideration relates to airflow.  To achieve one's required environmental conditions, the air in a cleanroom is purified using High Efficiency Particulate Air (HEPA) filters that can be designed to meet any classification. However, if you also want to control temperature and humidity, recirculating designs are often specified for their more precise control.

Design for Flexibility
Flexibly designed cleanrooms can easily accommodate needed expansions as well as modifications that may be required when new equipment or tools are introduced to the cleanroom. This allows changes to the cleanroom to happen rapidly and efficiently, which minimizes the number of contaminants that can be introduced to the room during the exchange process. Additionally, the quick change-over of equipment leads to reduced downtime and increases in productivity. If cleanrooms are designed with expandability and flexibility in mind, the cost of future change will be reduced.

Traditional vs. Modular
When considering the addition of a new cleanroom, there are two methods you can choose: Traditional or Modular. While each method has its own merits, PortaFab focuses on the implementation of modular wall systems to satisfy cleanroom design needs. Listed below are several benefits provided by a modular cleanroom installation.

Cost
Modular installation is often less costly than traditional construction as each component of the cleanroom is prefabricated and simply needs to be assembled once on site.

Alterations
As modular cleanrooms feature a non-progressive construction, they can often be altered easier without the debris and mess that comes with traditional construction.

Expansion
Modular cleanrooms are easy to expand, as the operation only requires adding additional wall, ceiling, and floor systems. Traditional construction may require the demolition of existing walls and systems to make way for new construction.

Choosing a Modular Cleanroom System
It’s important to understand a project’s requirements and separate the required must-haves from the aesthetic nice-to-haves (see table below). The design of cleanrooms and classified spaces requires that architectural finishes be designed to be smooth, easy to clean, non-shedding, and have minimal ledges and joints. Life science applications require radius corners for ease of cleaning, nonporous surfaces, and resistance to microbial and fungal growth. The architectural finishes should also be able to withstand repeated cleaning and sanitizing with various chemical solutions.

Common Cleanroom Configurations

Below are four common types of cleanroom configurations that can be used for a variety of different cleanroom applications.

1. Panel-Post Cleanrooms
Panel-post design is a popular and commonly used approach because the systems can be moved, reconfigured and expanded cleanly and easily. Utilizing a nominal 4-foot wide panel with a stud post, the stud post dismantles into two pieces, allowing a panel to be removed without disturbing other panels. All of the components can be reused in new configurations, and raceways built into the system allow easy access to utilities without endangering the classification or causing a rise in particle counts. These systems can also easily accommodate rack-mount utilities on chase walls and bulkhead openings.

2. Panel-Panel Cleanrooms
Used more within the pharmaceutical arena, these systems can provide non-progressive construction for removal of a single panel without disturbing adjacent panels. Panel edges are formed edges with dog-bone, tongue-and-groove or cam-lock mechanisms to connect a panel directly to another panel, eliminating the ledge of the panel-post design. Joints are sealed with a caulk joint or chemical weld, producing a wall system conducive to wash-down applications. Some systems offer raceways built within the panel itself; otherwise, utilities must be surface-mounted onto the face of the panel or fit-up at the chases. Radius coving at floor, ceiling and corner connections provide easily cleaned corners, and windows and door frames are flush-mount across the plane of the wall.

3. Double-Wall Cleanrooms
Double-wall clean room designs offer a unique solution for pharmaceutical applications. These systems integrate with a metal stud framework by hanging off one or both sides of the studs, creating a utility chase with a more economical panel. Panels have formed or cut edges to connect panels directly to one another and they utilize a caulk joint, gel coat or chemical weld, creating a smooth panel transition across the surface of the wall. Individual panels can be removed by striking the joints and removing the panel from the framework. Panel thicknesses are between 0.50 inch and 0.625 inch, and can provide an alternative to creating a chase wall from two thicker panels, which can be very costly. The use of a metal stud framework can also provide separate utility and electrical support and panels can be prepped for all fit-ups.

4. Furring Wall Cleanrooms
Furring wall systems can be attached to any solid wall or wall surface, including block, concrete and drywall. These systems are a good solution for upgrading existing areas in lieu of using a full freestanding panel, which can be very costly.