How to Ensure Proper Cleanroom Gowning and Prevent Contamination?  

Cleanroom Gowning Room
  The cleanroom gowning room is a preparatory area for personnel before entering the clean zone. It is primarily used for changing into cleanroom garments, shoes, caps, and other equipment to prevent external dust, bacteria, and other contaminants from entering the clean zone. This is an essential step to ensure cleanliness during the production process.

1. Sources of Contamination in Cleanroom Gowning Rooms
The primary sources of contamination in cleanroom gowning rooms include:
(1) Personnel Contamination: Human bodies are the primary source of contamination, shedding significant amounts of skin particles and microorganisms daily. These can disperse through movement, polluting the environment.
(2) Cleaning Supplies: Cleaning products used in the gowning room may produce particles and leave chemical residues, which can affect the cleanliness of the room.
(3) Clothing and Personal Care Products: During clothing changes, fibers from garments and particles from cosmetics, deodorants, or other personal care products can contaminate the air.
(4) Equipment and Systems: Devices such as air conditioning systems and lighting fixtures may emit particles or microorganisms due to inadequate maintenance or aging, compromising the room’s cleanliness.
(5) Adjacent Areas: Contaminants from nearby non-clean zones may enter via airflow or personnel movement.
   To maintain a clean environment, implementing targeted, effective control measures is essential for addressing these contamination risks.

2. Design and Classification of Cleanroom Gowning Rooms
  The gowning room is a key element in cleanroom design. To prevent external contaminants from entering and ensure compliance with cleanliness standards in production areas, the design of gowning rooms should follow these essential principles:
(1) Layout of Gowning Rooms:
  Gowning rooms should separate different stages of the gowning process into distinct areas, typically divided into a pre-stage and a post-stage. The pre-stage serves as an auxiliary area for initial preparation, such as changing shoes or removing outerwear. The post-stage includes donning cleanroom garments (sterile outerwear) and using airlocks for handwashing and disinfection. The final airlock serves to isolate airflow between the changing room and production areas, effectively preventing external contaminants from being introduced.
(2) Classification of Gowning Rooms:
  According to updated GMP standards, "the cleanliness level of the post-stage in a static state must match the clean zone it serves." Therefore, the post-stage (including donning clean garments and the airlock) should meet the same cleanliness level as the production area. The pre-stage, as an auxiliary zone, requires air filtered through HEPA filters, a defined air exchange rate, and a pressure gradient but does not need to meet specific cleanliness grades. Proper design and construction ensure that personnel do not introduce external contaminants during the changing process.
(3) Pressure Differential Settings:
  Pressure differentials in changing areas should direct airflow from higher-grade zones to lower-grade zones. The airlock must maintain the highest pressure, with adjacent rooms maintaining a pressure difference of 5–10 Pa. This prevents cross-contamination while avoiding excessive pressure build-up between clean and non-clean zones. Monitoring devices should be installed to ensure compliance with cleanroom requirements.
(4) Material Selection:
  To ensure durability and easy cleaning, materials must be corrosion-resistant, moisture-proof, and fire-resistant. Floors and walls should use smooth, seamless materials such as PVC flooring or stainless steel panels to minimize bacterial growth. High-touch areas like door handles should use antimicrobial materials, and all seams should be sealed to prevent dust and microorganisms from entering.
(5) Ventilation System:
  An efficient ventilation system is essential for controlling particle concentrations and maintaining air quality. GMP standards require cleanroom gowning rooms to maintain a slight positive pressure to prevent unfiltered external air from entering. HEPA filters must be installed to ensure incoming air meets cleanliness standards.
(6) Lighting:
  Adequate lighting improves work efficiency and helps identify potential contaminants. Light fixtures should be explosion-proof, waterproof, and easy to clean. Embedded LED lights are recommended for their low heat output and long lifespan.
(7)Temperature and Humidity Control:
  Maintaining appropriate temperature and humidity is critical for comfort and hygiene. Extreme temperatures can affect garment drying and increase microbial growth, while excessive humidity may lead to mold. The recommended temperature range is 20–25°C, with relative humidity between 45–65%.
(8) Signage and Guidelines:
  Clear, visible signage helps employees quickly locate equipment and understand procedures while promoting compliance. Examples include signs such as "No Personal Food Allowed" or "Turn Off Mobile Phones", and illustrated instructions for changing procedures.
(9) Garment Requirements:
  Staff in different production zones should wear distinguishable uniforms tailored to meet the air cleanliness standards of their respective areas, preventing cross-contamination during the changing process.
(10) Supporting Equipment:
 Gowning rooms should include standard wardrobes, clean wardrobes, shoe lockers, washbasins, hand sanitizers, and air showers. These ensure thorough cleaning of personnel and clothing before entering the clean zone, reducing contamination risks.
(11) Exit Passages:
  For high-cleanliness production areas or those requiring controlled exposure to specific substances (e.g., highly allergenic, toxic, or active materials), GMP guidelines recommend separate entrances and exits for changing rooms. Exit passages should include negative pressure traps to isolate airflow from production zones.

3. Dressing Procedures for Cleanroom Gowning Rooms
  Personnel must strictly follow dressing procedures when entering or exiting the cleanroom to ensure personal cleanliness. The dressing process includes the following steps:
(1)　Zoning of the  Room:
  The changing room is typically divided into different functional areas: the first stage (changing shoes and removing outerwear), the second stage (donning cleanroom garments, handwashing, and disinfection), and an airlock. When necessary, these zones can be separated by gender.
(2)　Preparation:
  Staff must ensure personal hygiene before entering the changing room from the general production area.
(3)　First Stage:
  The first stage is equipped with shoe benches, lockers for visitors, and lockers for staff. Upon entering, personnel must remove outerwear, hats, and shoes that may carry external contaminants and store them in designated lockers. They should then wash and disinfect their hands thoroughly.
(4)　Second Stage:
After crossing the shoe bench into the second stage, personnel should follow these steps to put on cleanroom garments:
♦Wear gloves to prevent contamination of clean garments during subsequent steps.
♦Put on a clean mask, ensuring it completely covers the nose and mouth to prevent contamination through breathing. Masks must not be removed inside the cleanroom.
♦Wear a clean cap, ensuring all hair is fully covered.
♦Put on cleanroom garments, ensuring they completely cover personal clothing. Garments must not touch the floor or walls. Fully close zippers and secure all fasteners.
♦Wear shoe covers, ensuring pant legs are tucked inside and zippers are closed. Pants must not extend over the outside of the shoe covers.
♦Put on clean gloves, ensuring sleeves are tucked into the gloves to avoid exposure.
♦Inspect the final appearance, ensuring no hair or skin is exposed.
♦Personnel must remain in cleanroom attire while inside the cleanroom. When exiting, they should remove cleanroom garments in reverse order to prevent contamination. Proper dressing and undressing procedures ensure garments remain uncontaminated and effective.
(5)　Precautions:
♦Smoking, eating, or applying makeup is strictly prohibited inside the cleanroom.
♦Changing personal clothing inside the cleanroom is not allowed.
♦Activities that generate dust or airborne contaminants are forbidden.
♦Non-clean items must not be brought into the cleanroom.
♦Cleanroom garments must not come into contact with the floor, walls, or other surfaces.
♦Garments must be handled carefully during dressing and undressing to prevent contamination.
♦Cleanroom garments should be regularly cleaned and disinfected to maintain cleanliness.
♦Damaged or contaminated garments must be replaced immediately.
♦Firefighting equipment must be available and regularly inspected.
(6)　Routine Monitoring and Inspection:
♦QA monitors and workshop supervisors are responsible for overseeing compliance with these procedures.
♦Cleanroom personnel and visitors must adhere to these standards.
♦Cleanroom garments should be inspected regularly to ensure they meet cleanliness requirements.

4. Intelligent Management of Cleanroom Gowning Rooms
With advancements in technology, intelligent management concepts have been widely adopted across industries. The intelligent management of cleanroom changing rooms enhances production efficiency while ensuring product quality and a clean working environment. Current intelligent management systems typically include the following:
(1) Intelligent Electrical Control Systems: Intelligent electrical control systems primarily consist of sensors, actuators, controllers, and monitoring software.
♦Sensors are responsible for real-time monitoring of various environmental parameters such as temperature, humidity, pressure, and particle concentration, transmitting this data to controllers.
♦Controllers process sensor data based on pre-set control logic and algorithms, sending corresponding instructions to actuators. Actuators adjust and control production equipment, ventilation systems, and air conditioning systems to ensure the cleanliness and stability of the production environment.
♦Monitoring software provides real-time system oversight and management through a visual interface, enabling convenient operation and maintenance by personnel.

  Therefore, intelligent electrical control systems offer the following features:
â‘  High-precision control: Accurately controls environmental parameters, ensuring product quality and production efficiency.
â‘¡ Intelligent management: Automatically monitors, adjusts, and controls the production environment, reducing the frequency and complexity of manual interventions.
â‘¢ Energy efficiency: Dynamically adjusts production equipment, ventilation systems, and air conditioning to effectively lower energy consumption and environmental impact.
â‘£ High reliability: Utilizes advanced sensors, actuators, and controllers to ensure stability and continuity in the production environment.

(2) Intelligent Management Equipment:
♦Intelligent management applied to equipment enhances both the modernization of gowning room management and user convenience. Examples include:
â‘  Smart wardrobes/shoe cabinets: Modern smart wardrobes and shoe cabinets may feature automatic identification systems such as RFID or biometric recognition, ensuring only authorized personnel can access them. This eliminates the need for traditional keys or passwords, reducing security risks and improving efficiency. Additionally, smart wardrobes can track usage data, predict potential issues, and schedule timely maintenance and adjustments.
â‘¡ Smart recycling devices: These devices automatically detect full bins, issue alerts, and track disposal volumes, enhancing operational efficiency and supporting production needs.

♦Challenges and Future Directions:
â‘  Despite their many benefits, smart wardrobes face challenges such as high initial development and maintenance costs. Additionally, the complexity of advanced systems requires staff and managers to possess adequate technical knowledge. Ensuring systems remain up-to-date and compatible with new technologies is also a key challenge.
â‘¡ In the future, the development of smart gowning room equipment may focus on cost reduction, improved user experience, and enhanced data security. As artificial intelligence and IoT technologies evolve, smart gowning room systems will achieve greater integration with other management systems, delivering higher levels of intelligent management and operational efficiency to cleanrooms.

Clean dressing room is a key link in clean room environmental control. This article analyzes in detail the pollution sources, design points, air purification, personnel changing process and intelligent management of clean dressing room to ensure compliance with GMP standards.