Cleanroom Gowning & De-gowning Procedures

Keeping cleanrooms contaminant-free is a critical part of maintaining a controlled environment. Cleanrooms are specifically designed to control airborne particles and other potential contaminants, but the facility itself is only one part of an effective contamination-control program.

The people entering and working inside a cleanroom can also introduce particles, microorganisms, fibers, hair, and other contaminants. That is why consistent gowning, de-gowning, entry, cleaning, and personnel procedures are so important.

For regulated sterile manufacturing environments, agencies such as the FDA specifically address personnel gowning and aseptic practices as part of contamination prevention.

What is a cleanroom?

A cleanroom is a controlled environment in which airborne particle concentrations are monitored and controlled according to defined requirements.

The ISO 14644 series provides internationally recognized standards for cleanrooms and associated controlled environments. ISO 14644-1 classifies air cleanliness according to the concentration of airborne particles, while ISO 14644-5 addresses operational considerations such as personnel, gowning, cleaning, maintenance, and monitoring.

Cleanrooms may also use HEPA filtration, controlled airflow, pressure differentials, airlocks, controlled material movement, and designated transition areas to reduce contamination risks.

However, cleanroom design alone cannot prevent contamination. The way people enter, dress, move, work, and exit the space also matters.

Why is a consistent gowning procedure important?

Personnel are an important potential source of contamination in controlled environments. Hair, skin particles, microorganisms, fibers, cosmetics, and particles carried on clothing or footwear can all be introduced when someone enters a cleanroom.

For that reason, cleanroom operations should include a documented personnel and gowning program appropriate for the facility and the work being performed. ISO 14644-5:2025 specifically includes a gowning program within cleanroom operational controls.

In aseptic pharmaceutical environments, FDA guidance goes further. It recommends written procedures for putting on each gown component in a way that prevents contamination and notes that garments should provide an effective barrier between personnel and exposed sterile materials.

A consistent procedure also supports the work performed through your cleanroom cleaning and contamination-control program.

Important: There is no single gowning sequence that applies to every cleanroom. Garments, gowning order, hand hygiene, air showers, sticky mats, glove requirements, and de-gowning procedures should follow your facility’s written SOPs, cleanroom classification, processes, and applicable regulatory requirements.

Cleanroom Gowning Procedure: Best Practices

The following is an example of a common cleanroom gowning workflow. Your facility’s approved gowning procedure should always take precedence.

Prepare for cleanroom gowning

Before entering the gowning area:

• Remove jewelry, makeup, outerwear, and other personal items as required by your facility’s procedures.
• Make sure required hair and facial-hair coverings are available.
• Follow the facility’s handwashing or hand-sanitizing procedure.
• Inspect required garments and PPE for visible damage or contamination before use.
• Use tacky or sticky mats where they are part of the facility’s contamination-control procedure.
• Prepare the approved garments and supplies needed before beginning the gowning process.

The EU’s current GMP Annex 1 for sterile medicinal products similarly states that items such as jewelry and makeup should not be permitted in clean areas and that cleanroom gowning and handwashing should follow written procedures designed to minimize contamination.

As you gown, avoid contaminating clean garments

Many facilities use a sequence that moves from head coverings toward the rest of the body while maintaining separation between less-clean and cleaner areas.

A typical procedure may include:

1. Put on the required hair cover or bouffant cap.
2. Add a beard or facial-hair cover when applicable.
3. Make sure all hair is completely contained.
4. Put on required eye protection.
5. Perform the required hand hygiene procedure.
6. Put on gloves if they are required at this stage of your facility’s gowning process.
7. Carefully put on the cleanroom coverall or gown.
8. Keep clean garments from touching the floor, bench, walls, or other potentially contaminated surfaces.
9. Put on a hood when required, making sure it overlaps appropriately with the gown or coverall.
10. Put on boot or shoe covers according to the facility’s clean-side/dirty-side procedure.
11. Put on or replace cleanroom gloves as required, ensuring appropriate overlap between gloves and garment sleeves.

Keeping gowns from touching the floor is particularly important in aseptic environments. FDA guidance identifies allowing sterile gowning apparel to contact the floor or other potentially contaminated surfaces as an example of a practice that can create insanitary conditions.

Before entering the cleanroom
Complete any final entry requirements specified by the facility.

These may include:

1. Sanitizing gloved hands with an approved agent.
2. Checking gown fit and coverage.
3. Crossing a designated clean-side boundary.
4. Passing through an airlock or air shower, if the facility uses one.
5. Entering the cleanroom according to the site’s approved entry procedure.

Not every cleanroom uses an air shower, and not every environment requires double gloves. Those requirements should be determined by the facility’s contamination-control program rather than treated as universal cleanroom rules.

Pegasus’ cleanroom services include support for gowning rooms, material management, contamination control, and protocol development for controlled environments.

Cleanroom Protocol for De-gowning: Best Practices

De-gowning should also follow a documented procedure designed to prevent contaminants from being transferred from garments, equipment, or personnel into cleaner areas.

A typical de-gowning process may include:

1. Move into the designated de-gowning or transition area.
2. Remove boot or shoe covers according to the facility’s clean/dirty boundary procedure.
3. Remove the outer pair of gloves if double-gloving is required.
4. Carefully remove the coverall or gown without allowing potentially contaminated exterior surfaces to contact clothing or clean surfaces.
5. Place reusable garments in the designated collection area or discard single-use garments as instructed.
6. Remove and properly store or dispose of eye protection.
7. Remove the hood if one is worn.
8. Remove the face mask and hair covering according to the facility’s procedure.
9. Remove the final pair of gloves.
10. Dispose of single-use items and place reusable items into their designated containers.
11. Perform final hand hygiene as required by the facility.

The exact order may vary depending on the cleanroom and the contamination risks involved. In sterile pharmaceutical operations, gowning and de-gowning procedures are generally established through formal written procedures, personnel training, qualification, and ongoing monitoring.

Cleanroom Gowning Is Only One Part of Contamination Control

A properly designed gowning procedure helps reduce the risk of personnel carrying contamination into a controlled environment, but gowning cannot replace a comprehensive cleanroom cleaning and contamination-control program.

Facilities should also consider:

• routine cleanroom cleaning and disinfection
• personnel training
• material-transfer procedures
• gowning room maintenance
• environmental monitoring
• approved cleaning products and tools
• equipment and surface cleaning
• documentation and written SOPs

ISO 14644-5 addresses many of these operational elements as part of maintaining a cleanroom within its specified cleanliness requirements.

Pegasus provides specialized cleanroom cleaning services for cleanrooms, laboratories, gown rooms, GMP facilities, and other controlled environments.

Services can include routine cleaning, contamination-control programs, protocol and SOP development, environmental monitoring support, and specialized decontamination.

Need help maintaining your cleanroom?

Maintaining a controlled environment requires more than cleaning visible surfaces.

Pegasus develops cleaning programs around the requirements of each facility, helping organizations maintain cleanrooms, gowning areas, laboratories, and other critical spaces.