Air Curtains vs Airlocks: Which Is Right for Your Cleanroom Entrance?

 

When planning a cleanroom facility, one question comes up quite often: Can an air curtain be used instead of an airlock?

It’s a fair question. Airlocks are expensive, require additional floor space, and can slow down the movement of people and materials. An air curtain, on the other hand, is easier to install and allows continuous movement through a doorway.

But the answer really depends on where the door is located and what that entrance is expected to control.

Air curtains and airlocks may both be described as barriers, but they serve very different purposes. Understanding that difference at the planning stage can prevent costly design and contamination-control problems later.

What Is an Airlock Designed to Do?

An airlock is a physical transition chamber between two areas with different cleanliness or pressure requirements.

It normally has two interlocked doors, designed so that both doors cannot be opened at the same time. This creates a controlled separation between the classified cleanroom and the surrounding area.

In GMP and classified cleanroom environments, airlocks play an important role in maintaining pressure cascades, supporting gowning procedures, and controlling the movement of personnel and materials.

Most importantly, they prevent a direct open path between a controlled area and an uncontrolled or lower-grade environment.

For entrances where the cleanroom classification changes, an airlock is generally an essential part of the facility design.

What Does an Air Curtain Do?

An air curtain works on a completely different principle.

It produces a continuous, high-velocity stream of air across an open doorway. This airflow creates an aerodynamic barrier that helps reduce the entry of dust, insects, outside air, and humidity.

The biggest advantage is that people, trolleys, and materials can continue moving through the entrance without waiting for doors to close or an airlock cycle to complete.

This makes air curtains particularly useful for busy entrances and high-traffic areas.

However, an air curtain does not provide complete physical separation. It also cannot maintain a true pressure differential in the same way as a properly designed airlock.

A correctly selected and installed air curtain can significantly reduce unwanted air exchange, but it cannot eliminate it completely.

So, Which One Should You Use at a Cleanroom Entrance?

If the doorway is the actual boundary between an uncontrolled or lower-grade area and an ISO-classified cleanroom, an air curtain should not be considered a replacement for an airlock.

Personnel entrances, gowning areas, material transfer points, and production entrances where the cleanroom classification changes require proper contamination-control planning. In these areas, the airlock performs a function that an air curtain simply cannot replace.

Air curtains are most effective before the classified boundary.

Think about facility entrances, loading bays, warehouse doors, and general production-floor entrances leading towards the cleanroom.

These are areas where dust, humid outside air, insects, and other environmental contaminants can enter the facility. Installing an air curtain at these locations helps reduce the environmental load before it reaches the airlock or cleanroom.

For example, an air curtain installed at a loading dock can reduce the amount of humid air and dust entering whenever goods are moved in or out.

As a result, the airlock and cleanroom start with a cleaner and more controlled environment. This can also reduce the load on HVAC and dehumidification systems operating inside the facility.

In Many Facilities, the Best Solution Is to Use Both

The decision does not always have to be air curtain versus airlock.

In a properly planned facility, the two systems can work together.

Use airlocks where the cleanroom classification or pressure zone changes. Use air curtains at high-traffic entrances where you want to reduce dust, insects, humidity, and outside air before they reach the controlled area.

This approach can help reduce particulate load near gowning and transfer areas, improve environmental control, and reduce unnecessary strain on cleanroom humidity-control systems.

For general production-floor and warehouse entrances leading towards classified areas, continuous-duty industrial air curtains are generally the better choice. Models such as the FDS Industrial Air Curtain are suitable for high-traffic doorways where the equipment may need to operate for long hours.

For hazardous or chemical-adjacent areas in pharmaceutical facilities, the EOHV-A Flame Proof Air Curtain can be considered where suitable flame-proof equipment is required.

For office entrances, reception areas, and other lighter-traffic doorways, a standard commercial air curtain is usually sufficient.

A Simple Way to Decide

Ask one question:

Does the cleanroom classification or controlled pressure zone change on the other side of this door?

If the answer is yes, the entrance should be evaluated for an airlock. An air curtain cannot replace the controlled separation provided by an interlocked airlock.

If the answer is no, and the main concern is reducing dust, insects, humidity, or outside air entering through a frequently used doorway, an air curtain may be the more practical and cost-effective solution.

The right solution often comes down to understanding the complete facility layout. Identifying which entrances require airlocks, where air curtains can reduce environmental load, and where both systems should work together can prevent contamination and humidity-control problems later.

Not sure which entrances in your facility need an airlock and which would benefit from an air curtain?

Contact JET INDIA for a facility layout review and suitable air curtain recommendation.

Call: 022 4343 2323
Email: inquiry@jetindia.co.in