In pharmaceutical production, sterility isn’t just a benchmark—it’s the foundation on which every operation stands. Inside a cleanroom, air, surfaces, and personnel movement are all tightly controlled to keep contamination out. One of the least visible yet most important safeguards in that effort is the airlock.
For Aldo Vidinha, Senior Technical Operations Freelance Consultant, airlocks are more than transitional spaces between rooms. They are precision-engineered control zones that protect the integrity of an entire manufacturing system.
“Cleanrooms depend on balance,” Vidinha says. “If you lose that balance, even for a moment, you compromise quality.”
A Barrier Between Worlds
An airlock sits between two spaces—usually between a cleanroom and a less controlled area—and maintains a small but critical pressure difference, typically around 10 to 15 pascals. This pressure keeps air flowing in the right direction, preventing contaminants from drifting into sterile zones. In practice, airlocks serve three main purposes: they prevent cross-contamination, manage the transfer of personnel and materials, and maintain the sterility of high-grade areas.
“An airlock’s job is simple,” Vidinha explains. “It keeps the clean side clean.”
Different Types for Different Tasks
Pharmaceutical plants use several kinds of airlocks, each tailored to a specific function. Personnel Airlocks (PALs) manage operator entry and exit, while Material Airlocks (MALs) handle the movement of tools, containers, or raw materials. Both designs use interlocking doors so that only one can open at a time, maintaining the required pressure gradient. “The interlock mechanism is straightforward but vital,” Vidinha notes. “It ensures that air moves only one way—toward cleaner spaces.”
Bubble, Sink, or Cascade
Not all airlocks work the same way. Bubble airlocks keep higher pressure inside, pushing clean air outward to block contaminants. Sink airlocks create negative pressure, drawing air in to trap potential contaminants within the chamber. The cascade system manages multiple zones with pressure changes in sequence—usually from 30 pascals to 10—to guide airflow from the cleanest zone toward the least clean.
Each method has a place, depending on how a facility handles product, personnel, and flow. “Choosing the right setup is about understanding both process and behavior,” Vidinha says. “Technology can enforce standards, but people make them work.”
Designing for Compliance and Everyday Use
Regulators like the FDA and EMA increasingly focus on how facilities control airflow and prevent contamination, and airlock design has become part of that conversation. For Vidinha, the best systems don’t just meet guidelines—they make good practices second nature.
“A well-designed airlock supports discipline,” he says. “Operators should feel the logic of the system as they move through it.”
Modern designs often include pressure sensors, alarms, and automatic data logging to verify compliance and document every interaction. These systems strengthen accountability while helping facilities track and refine performance over time.
Looking Ahead
The next generation of airlocks is already emerging. Vidinha points to a future where cleanrooms are supported by self-adjusting systems that automatically balance pressure and airflow in real time.
“Automation is making it possible to anticipate changes before they happen,” he says. “We’re moving from reaction to prevention.”
But even with advanced controls, the underlying principle remains the same: consistency. “Airlocks might be small,” Vidinha adds, “but they protect the most valuable things we have—our products, our patients, and our reputation.”
