top of page
  • Writer's pictureCleanroomsUSA

Types of Cleanrooms

There are a combination of factors that determine the classification of the type of cleanroom. Airflow for cleanrooms is crucial since it determines the AHC and air movement, which enhances the removal of detrimental particles from the air. Aligned with airflow is the construction of a cleanroom, which influences the smoothness of the air exchange rate.

Types of Cleanroom Airflow

Cleanrooms utilize two main types of airflow: unidirectional and turbulent.

Unidirectional airflow involves air entering the cleanroom from the filtration system and exiting through the venting system. Typically, the airflow moves downward, but this can vary based on the cleanroom's design.

Turbulent airflow, also known as vortex airflow, involves the input air mixing with the air already in the cleanroom. The mixed air then exits through wall vents, where it's filtered and recycled. As the air enters the cleanroom, it swirls, creating eddies and mixing with the existing air in a non-directional pattern.

In unidirectional airflow, also called laminar airflow, the air moves in a straight, unobstructed path, parallel to each other. This airflow is directed downward horizontally, sweeping across the cleanroom and gathering contaminants in a parabolic velocity profile. Laminar airflow hoods are designed to direct air jets downward.

Cleanroom Construction

The term "cleanroom" encompasses a broad spectrum of designs and configurations, ranging from small, portable soft-walled rooms to large-scale production cleanrooms. Despite the variation in construction, all cleanrooms must adhere to ISO standards.

Hardwall modular cleanrooms feature aluminum supports and rigid walls designed to withstand increased air pressure. The solid walls are typically three inches thick and constructed from various materials, coated with a plastic resin to facilitate easy cleaning. These modular cleanrooms are portable, with hardwalls that can be disassembled for repositioning.


Softwall cleanrooms feature walls made of vinyl or other plastic materials. They are compact and portable, allowing them to be positioned close to assembly operations and manufacturing processes. Softwall cleanrooms offer an affordable solution for creating a controlled environment and typically have ISO ratings of 5 and above. Similar to modular cleanrooms, softwall cleanrooms have an aluminum or coated steel frame and contain all the necessary components of larger cleanrooms but in smaller sizes.

Powder Containment

Powder containment cleanrooms are a safety precaution designed to shield workers from hazardous substances. These cleanrooms are specifically engineered to fulfill requirements for weighing, capsule filling, and compounding creams while ensuring containment and filtration. Equipped with airflow and filtration systems, powder containment cleanrooms are capable of handling hazardous powders, dust, and fumes. They incorporate a recirculation system that continuously filters particles from the air, maintaining a clean environment.

Explosion Proof

All cleanrooms are designed to be explosion-proof, serving as sealed and self-contained environments. However, for industries dealing with volatile substances, additional safety features are incorporated to provide enhanced protection for workers. Explosion-proof cleanrooms feature specialized ceiling components, control panels, and wall panels, along with non-sparking lighting equipped with static dissipative PVC to guard against Electrostatic Discharges (ESDs).

Moreover, the frames of explosion-proof cleanrooms are constructed from extra-strength powder-coated steel for added durability and safety.

Fire Resistance

Fire resistance is a standard feature of all cleanrooms because their walls are designed to be chemical, thermal, and fire resistant. To qualify as fire resistant, a cleanroom wall must meet the ASTM E 84 Class A smoke and fire rating standards and comply with ISO classifications 2 to 9 requirements.

Typical wall construction for fire resistance involves an outer layer of gypsum over a polyurethane core, with surfaces made of vinyl, steel, or aluminum. Gypsum provides the fire resistance, while the surfaces are chosen for their ease of cleaning.

BioSafe Cleanroom

Biosafe cleanrooms are specifically designed to accommodate aseptic processes and adhere to ISO standards ranging from ISO 4 to ISO 8. These cleanrooms feature walls made of stainless steel or powder-coated steel for easy cleaning. Like other cleanroom types, biosafe cleanrooms are equipped with interlocking panels to withstand or prevent vibration and instability.

Since air supply systems are common in most cleanrooms for handling bio materials, biosafe cleanrooms utilize HEPA filtration systems similar to those in other cleanroom types. Typically, biosafe cleanrooms are configured with a unidirectional airflow pattern.


  • Cleanrooms are specially designed enclosures that are designed to eliminate contaminants and microorganisms.

  • The purity of the air in a cleanroom is determined by the number of µm particles there are in one cubic meter of air.

  • There are several classifications used to identify a cleanroom. The International Organization of Standardization (ISO) is the most widely accepted.

  • There are strict guidelines for clothing worn by workers in a cleanroom.

  • The most important component in a cleanroom is its air exchange unit.

  • Airflow in a clean room can be unidirectional or turbulent.

  • The two construction designs of cleanrooms are modular and permanent or stick.

- - -

Contact us today and one of our cleanroom experts will discuss the best path forwards for your project.


Recent Posts

See All


bottom of page