It's not just the four walls of a cleanroom that prevent contamination—it’s the components and equipment of the cleanroom that preserve the integrity of these environments. One critical component is an airlock system. They serve as transitional barriers that prevent the ingress of contaminants during the periods of movement. In industries like pharmaceuticals, biotechnology, and semiconductor manufacturing, airlocks help provide the protection necessary for products, personnel, and compliance regulations.
An airlock is a sealed chamber with multiple interconnected doors, strategically positioned between your cleanroom and the rest of your facility. Their configuration ensures that only one door can be opened electronically at a time, preventing direct airflow between your cleanroom and adjacent spaces with differing cleanliness levels.
To prevent contamination, airlocks utilize specific air pressure differentials. These differentials happen when two spaces have different air pressures. One everyday example is when air rushes out upon popping a balloon. These differences cause air to move from the high-pressure area to the low-pressure area. By maintaining specific pressure gradients, airlocks effectively minimize the transfer of particulates and microorganisms into our out of the cleanroom.
The operational sequence of an airlock typically involves personnel entering the airlock from a less controlled environment, closing the outer door, and allowing the system to stabilize the internal conditions—such as pressure, temperature, and humidity—to match those of the cleanroom. Once equilibrium is achieved, the inner door can be opened, permitting access to the cleanroom without compromising its integrity. This process is essential for maintaining the stringent environmental standards required in sensitive manufacturing, development, and research applications.
The airlock you choose must align with the specific contamination control requirements of your industry and application. Across all types of airlock systems, the doors should feature window panels allowing personnel to see who is entering or leaving the chamber. The primary types of airlock doors for cleanrooms include:
In a cascade airlock system, the pressure is highest in the cleanroom and decreases progressively through the airlock to the less controlled area. This arrangement causes air to flow outward from the cleanroom, preventing contaminants from entering. Cascade airlocks are commonly employed in facilities where the primary objective is to protect the product from external contamination, such as in pharmaceutical manufacturing.
Bubble airlocks maintain the highest pressure within the airlock itself, with lower pressures on both the cleanroom and external sides. This positive pressure barrier ensures that any potential contaminants are pushed back into their respective areas, thereby preventing cross-contamination. Bubble airlocks are particularly useful in scenarios where both the product and external environment require protection from each other, such as in handling potent compounds.
Conversely, sink airlocks operate with the lowest pressure within the airlock, while higher pressures are maintained on both the cleanroom and external sides. This negative pressure setup draws air from adjacent areas into the airlock, effectively containing any contaminants within the airlock space. Sink airlocks are typically utilized in facilities dealing with hazardous substances, where it is imperative to prevent contaminants from escaping into the external environment.
Pass-through chambers, also known as pass boxes, are specialized airlocks designed for the transfer of materials into and out of the cleanroom. Pass-through chambers are essential for minimizing personnel movement and reducing the risk of contamination during material transfer processes. Larger pass-through chambers are typically called material airlocks.
Implementing airlocks within cleanroom environments offers several advantages, ranging from contamination control to operational efficiency.
The security requirements of a cleanroom dictate the design and features of its airlock system. Many industries rely on secure airlock doors for cleanrooms to protect sensitive processes and intellectual property. Key security features for airlocks include:
Regular maintenance and monitoring not only uphold contamination control but also extend the lifespan of your airlock system. Specifically, scheduled inspections are fundamental to assess the effectiveness and operational status of your airlocks. These evaluations should encompass critical components such as interlock mechanisms, bottom seal sweepers, door closers, and Magnehelic gauges. Regular scrutiny of these elements aids in the early detection and rectification of wear or malfunctions.
Attention to airflow components is also critical. Regular inspection and replacement of prefilters on return air and makeup air grills are necessary to maintain proper airflow and prevent contamination. Neglecting these components can lead to decreased air quality and increased particulate levels within the cleanroom.
In addition to mechanical assessments, maintaining cleanliness within the airlock is paramount. Routine cleaning and disinfection of door handles, seals, and interior surfaces are essential to prevent the transfer of contaminants between controlled environments.
Environmental monitoring within the airlock further bolsters contamination control efforts. Installing a Magnehelic® gauge or digital display in cleanroom airlocks is essential for accurately monitoring differential pressure. By measuring the pressure difference between the cleanroom and adjacent areas, these devices ensure your airlock maintains the correct pressure gradient to prevent contamination.
At Encompass Cleanrooms, our team of experts specializes in the design and construction of both secure and non-secure airlock systems tailored to your facility's specific needs. We can recommend the most suitable airlock configurations to integrate other custom features that align with your operational requirements. Our commitment to quality ensures that your cleanroom maintains the highest standards of contamination control and security. If you have any questions or would like a personalized quote, contact the Encompass Cleanrooms team today.