Planning Personnel and Material Movement in a Cleanroom Facility

Why Movement Planning Matters

Personnel and materials are the primary sources of contamination in a cleanroom. Every time a person enters or exits the controlled area, or a material is transferred across a classification boundary, there is a risk of introducing particles, microorganisms or chemical contaminants. A well-planned movement strategy minimises these risks by defining controlled routes, using appropriate transfer equipment and establishing clear procedures for each type of movement.

Personnel Entry Sequence

The personnel entry sequence typically begins in an uncontrolled area where outdoor clothing is removed and stored. The person then progresses through a series of change rooms of increasing cleanliness, donning cleanroom garments at each stage. The final stage before entering the cleanroom may include an air shower to remove surface particles from the garments. The number of change stages and the garment requirements depend on the cleanroom classification and the applicable regulatory guidance.

Material Entry Sequence

Materials entering the cleanroom must be decontaminated or transferred through a controlled interface. Outer packaging is typically removed in an ante-room or airlock. Inner packaging may be wiped with an approved disinfectant before being passed through a pass box into the cleanroom. For large items that cannot pass through a pass box, a material airlock with appropriate pressure relationships and cleaning procedures must be provided.

Change-Room Progression

Change rooms should be designed so that the person moves progressively from a less clean to a more clean environment without the possibility of bypassing any stage. Interlocked doors between change rooms prevent simultaneous access from both sides and reinforce the one-way flow principle. Bench seating at the boundary between shoe-change and gown-change areas helps enforce the physical separation between the clean and non-clean sides of the change room.

Pass-Box Placement

Pass boxes should be positioned at the boundary between areas of different cleanliness classification, at a height and location that allows convenient use without requiring personnel to lean into the cleanroom. The pass box should be sized for the largest item that will regularly be transferred. Multiple pass boxes may be required if different types of materials — for example, raw materials and finished product — must be kept separate.

Air-Shower Placement

Air showers are typically positioned at the final entry point to the cleanroom, after the gowning sequence is complete. Placing the air shower before gowning is ineffective because the garments applied after the air shower will re-introduce particles. The air shower should be sized and positioned so that it does not create a bottleneck during shift changes.

Dirty and Clean-Side Separation

The physical separation between the dirty side and the clean side of the facility must be maintained throughout the working day. Maintenance personnel, waste removal routes and equipment return paths must be planned so that they do not cross the clean-side boundary without following the appropriate entry procedure. Colour-coded floor markings, signage and procedural controls support physical separation.

Pressure Cascade Considerations

The pressure cascade — the arrangement of positive and negative pressure differentials between adjacent rooms — is a fundamental element of the contamination control strategy. The direction of airflow through any gap or opening should always be from the cleaner area to the less clean area. Pass boxes and airlocks must be designed to maintain the pressure cascade when doors are opened.

Cross-Contamination Risks

Cross-contamination between different products or materials is a specific risk in multi-product facilities. Dedicated entry routes, separate pass boxes and time-separated transfers may be required. The risk assessment for cross-contamination should be documented and reviewed as part of the facility qualification.

Maintenance Movement

Maintenance activities introduce a higher contamination risk than normal production operations because they may involve opening equipment, disturbing surfaces and introducing tools and materials that have not been through the normal decontamination procedure. A specific maintenance entry procedure, including appropriate gowning and equipment decontamination, should be defined and followed.

Emergency Egress

Emergency egress routes must allow rapid exit from the cleanroom without requiring personnel to follow the normal exit procedure. Emergency exits must be clearly marked, unobstructed and equipped with panic hardware. The emergency egress route should not pass through areas where hazardous materials are stored or processed.

Coordination Checklist

Before finalising the cleanroom layout, confirm: the number of personnel entering and exiting per shift; the types and volumes of materials being transferred; the cleanliness classification of each area; the pressure cascade design; the location and type of pass boxes and air showers; the change-room progression and gowning sequence; the maintenance entry procedure; and the emergency egress routes. The final cleanroom layout and classification strategy must be approved by the responsible project consultants and users.