Clean Room Gowning Procedure

In industries such as semiconductor manufacturing, biotechnology, pharmaceuticals, and aerospace, maintaining a controlled environment is paramount. The smallest particle of dust or a microscopic contaminant can compromise the integrity of a product or research experiment. To mitigate this risk, personnel must adhere to a strict clean room gowning procedure. This guide outlines the standard protocols for entering a controlled environment, ensuring the safety of both the personnel and the product.

The Purpose of Gowning

Human beings are the primary source of contamination in a clean room. Our bodies constantly shed skin flakes, hair, and oils. We also emit particles from our clothing and cosmetics. The purpose of the gowning procedure is to create a barrier between the operator and the clean room environment, containing these potential contaminants.

A typical gowning system consists of specialized garments designed to filter particles and trap human debris. These garments are constructed from non-linting, synthetic fabrics and are worn in a specific sequence to minimize the risk of re-contaminating the sterile exterior of the suit.

Pre-Gowning Preparation

Before entering the gowning room (often called the ante-room), personnel must prepare themselves to reduce the bioburden they carry.

• Personal Hygiene: Showering or bathing immediately before the shift is highly recommended. This removes dead skin and excess oils.
• No Cosmetics: Do not wear makeup, hairspray, perfume, cologne, aftershave, or deodorant. These products emit volatile organic compounds (VOCs) and often contain pigments that can shed particles.
• Jewelry and Accessory Removal: All jewelry, including watches, rings, necklaces, earrings, and piercings, must be removed. These items trap dirt and can snag fabrics. Wedding bands made of smooth, non-porous metal are sometimes permitted if taped over, but strict protocols usually require full removal.
• Attire: Wear only clean, dedicated facility undergarments or street clothes that produce minimal lint.
• Foods and Drinks: Chewing gum, eating, or drinking is prohibited in the gowning area and the clean room to reduce particulate generation.

The Gowning Area Protocol

The gowning area is divided into a "dirty" side (street clothes side) and a "clean" side (clean room side). The procedure moves from the dirty side to the clean side.

Upon entering the gowning area:

• Remove street shoes and place them in the designated locker or cubicle.
• Perform a thorough hand wash using antibacterial soap and warm water. Wash up to the elbows for at least 30 seconds. Dry hands completely with a paper towel (do not use cloth towels which generate lint).

Step-by-Step Gowning Sequence

The Gowning Verification

Before entering the clean room, perform a self-inspection or utilize a "buddy system" where a colleague checks your gowning. Look for the following:

• Is all skin covered?
• Is the mask secure under the chin?
• Are all zippers and snaps closed?
• Is the suit tucked in properly at the boots and gloves?
• Is there a gap between the hood and the collar?
• Is there excessive lint or loose hair on the shoulders?

If any deficiencies are found, correct them at the gowning bench. Do not enter the clean room until the barrier is intact.

Behavior Inside the Clean Room

Gowning is only half the battle; behavior inside the clean room is equally vital.

• Move Slowly: Fast movements create turbulence that stirs up particles from the floor and surfaces. Walk slowly and deliberately.
• Minimize Talking: Talking ejects saliva particles. Communication should be kept to a minimum or conducted via electronic devices.
• Posture: Avoid leaning against walls, benches, or equipment. Do not sit on the floor. Keep the body upright to allow laminar airflow to carry particles away from the critical work area.
• No Leaning: Never place hands in pockets (which can collect lint) or cross arms, which can create turbulence.

Air Showers (If Applicable)

Many modern clean rooms utilize an air shower between the gowning room and the production floor. This is an interlocked chamber with high-velocity HEPA-filtered air jets.

When entering the air shower:

• Stand with feet apart and arms raised to allow the air to clean the armpits and gown folds.
• Rotate slowly 360 degrees.
• The cycle typically lasts 20 to 30 seconds.
• The air shower dislodges loose particles from the gown's surface and blows them away through filters.

Degowning Procedure

When leaving the clean room, the degowning procedure is followed. This is essentially the reverse of gowning, with the primary goal of preventing the contaminated outside of the gown from touching the clean street clothes or skin.

1. Enter the degowning room.
2. Remove gloves carefully, turning them inside out so the contaminated surface is contained within. Dispose of them in the designated waste bin.
3. Remove goggles and place them in the cleaning/reprocessing bin.
4. Remove the coveralls. Unzip it completely and peel it off from the inside out, turning the suit so the contaminated surface is on the inside.
5. Remove the face mask by grasping the straps behind the earsdo not touch the front of the mask.
6. Remove the hair covering and beard cover carefully to avoid shedding trapped hair.
7. Remove boot covers. Step out of them without touching the outside.
8. Wash hands thoroughly after discarding all garments.
9. Put on street shoes and exit.

Conclusion

The clean room gowning procedure is a disciplined process that serves as the first line of defense against contamination. While the sequence of steps may vary slightly depending on the specific classification of the clean room (ISO Class 1 to ISO Class 9) or industry regulations, the fundamental principles remain the same: cover the body completely, minimize particles, and maintain strict discipline. By adhering to this protocol, companies ensure the quality and reliability of their high-precision products.