Correct Attire in the Clean Room

Cleanrooms are highly controlled and designed environments used to prevent the entry and spread of contaminants. These environments are commonly used in industries such as semiconductor manufacturing, biopharmaceuticals, food processing, and aerospace. To maintain high standards of air quality and a contamination-free state within the cleanroom, anyone entering must wear specific protective clothing and equipment. So, what should we wear in a cleanroom?



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The Importance and Basic Principles of Cleanroom Attire

The Importance and Basic Principles of Cleanroom Attire

Cleanrooms are controlled environments widely used in industries such as semiconductor manufacturing, pharmaceuticals, biotechnology, and medical device production. To ensure air quality and prevent contamination within the cleanroom, the attire of personnel is crucial. The primary purpose of cleanroom attire is to prevent contaminants from entering the clean area. Humans are a major source of contaminants, including skin flakes, hair, sweat, and fibers from clothing. Proper attire not only prevents external contaminants from entering the cleanroom but also protects products and research outcomes, ensuring the safety and health of the staff.


The Importance of Cleanroom Attire

Preventing Contamination

Human Body as a Contaminant Source: The human body releases numerous particles, such as skin flakes, hair, sweat, and respiratory secretions, which are major sources of contamination in cleanrooms.

Protecting Products: Products manufactured in cleanrooms, such as semiconductor chips and pharmaceuticals, are highly sensitive to contaminants. Even minimal contamination can lead to product failure or pose health risks to users.


Ensuring Staff Health

Ensuring Staff Health

Preventing Chemical Contamination: Some cleanrooms handle toxic and hazardous chemicals. Proper attire protects staff from chemical exposure.

Preventing Biological Contamination: In biosafety cleanrooms, appropriate protective clothing prevents pathogen infection.


Maintaining Cleanroom Environment

Controlling Particle Count: Proper attire effectively reduces the release of particles from the human body, maintaining the cleanroom’s air quality.

Preventing Cross-Contamination: Cross-contamination between different cleanroom areas is a significant management challenge. Correct attire can effectively prevent this issue.


Basic Principles of Cleanroom Attire

Full Body Coverage:

Protective clothing should cover the entire body, including the head, face, hands, and feet, ensuring no exposed skin or hair.

Use one-piece coveralls or two-piece suits, along with hoods, masks, gloves, and boot covers.


Dust-Free and Sterile:

Dust-Free and Sterile

All attire should be treated to be dust-free and sterile, preventing the introduction of external contaminants into the cleanroom.

Protective clothing should be donned in a designated cleanroom changing area to avoid contamination during the dressing process.



In electronics and semiconductor manufacturing, static electricity can damage products, making it essential to wear anti-static garments and footwear.


Fit and Comfort:

Protective clothing should fit well without being too tight, allowing free movement and reducing unnecessary actions that could increase contamination risk due to discomfort.


Durability and Easy Cleaning:

Durability and Easy Cleaning

Choose durable and easy-to-clean materials to ensure that protective clothing can be used for extended periods and is easy to maintain, preserving its protective properties.


Basic Equipment for Cleanroom Attire

Protective Clothing:


Full-body coveralls designed to prevent exposed skin from coming into contact with airborne particles and contaminants.

Two-Piece Suits: 

Separate top and pants design that provides full-body protection while offering easier wearability.


Hoods and Masks:


Fully cover the head, including hair and ears, to prevent hair and skin flakes from entering the cleanroom environment.

Masks or Face Masks: 

Masks or Face Masks

Cover the mouth and nose to prevent respiratory particles from entering the environment and provide additional protection.



Powder-Free Gloves: 

Prevent dust contamination and provide hand protection. Choose suitable glove materials based on specific needs.


Shoe Covers or Cleanroom Shoes:

Disposable Shoe Covers: 

Cover external shoes to prevent ground contaminants from entering the cleanroom.

Cleanroom Shoes: 

Specifically designed for cleanroom environments, these shoes are non-slip, easy to clean, anti-static, and provide foot protection.


Other Equipment:


Secure hair to the head to prevent hair from falling out.



Protect eyes from particles or chemicals, suitable for specific cleanroom environments.


Protect ears from noise interference or chemical exposure.

The above equipment constitutes the basic attire for working in a cleanroom. Depending on the cleanliness requirements and work environment, adjustments may be necessary.


Attire Requirements for Different Cleanroom Levels

In cleanrooms of varying levels, the attire requirements differ, but the goal remains the same: to minimize the introduction of particles and contaminants by personnel, ensuring the cleanliness of the cleanroom.


ISO 9 Cleanroom

Basic Protective Gear: 

Wear clean work clothes, including a hood, dust coat, pants, and cleanroom shoes.


Powder-free gloves are recommended, but the cleanliness requirement is lower.

Simple Facial Protection:

Simple Facial Protection

Wearing a mask or face shield is optional to reduce the entry of respiratory particles.


ISO 8 Cleanroom

Protective Clothing:

Similar to ISO 7 but with slightly lower cleanliness requirements.

Hoods and Masks:

In addition to a hood, wearing a mask or face shield is recommended to prevent respiratory particles from entering the cleanroom.


Use powder-free gloves, with lower cleanliness requirements.

Cleanroom Shoes:

Cleanroom Shoes

 Required to maintain the cleanliness of the cleanroom.


ISO 7 Cleanroom

Protective Clothing:

Full-body protective clothing, including a hood, dust coat, pants, and shoe covers. Choose materials with high cleanliness, such as polyester fibers.


Covers the head to prevent hair and skin flakes from entering the environment.


Use powder-free gloves to ensure hands do not release particles. Gloves should be changed frequently to maintain cleanliness.

Cleanroom Shoes:

Must be worn to prevent external contaminants from entering the cleanroom.


ISO 6 Cleanroom

Protective Clothing:

Protective Clothing

Full-body coveralls, including head, hands, and feet, typically made from polyester fiber material.


Covers the head to prevent hair and skin flakes from entering the environment.


Use powder-free gloves to ensure hands do not release particles.

Shoe Covers or Cleanroom Shoes:

Disposable shoe covers or cleanroom shoes to prevent external contaminants from entering the cleanroom.


ISO 5 Cleanroom

Protective Clothing: 

Similar to ISO 6 but with higher cleanliness requirements.

Hoods and Masks: 

In addition to a hood, a face mask or shield may be required to prevent respiratory particles from entering the cleanroom.


Use powder-free gloves with higher cleanliness requirements.

Cleanroom Shoes: 

Cleanroom Shoes

Must be specially designed cleanroom shoes with anti-static and non-slip features.


ISO 4 and Higher Cleanrooms

Full Protective Gear: 

Includes hood, coveralls, gloves, shoe covers, and all equipment must meet strict cleanliness requirements.

Special Protective Equipment:

May require special masks, goggles, anti-static clothing, etc., to meet higher cleanliness standards.

Strict Gowning Procedures:

Rigorous gowning and handwashing procedures before entering the cleanroom to ensure no external contaminants are brought in.


Dressing and Changing Procedures

Proper dressing and changing sequences are crucial in cleanrooms to ensure the environment remains uncontaminated.


Preparation Before Entering the Cleanroom

Preparation Before Entering the Cleanroom

Clean Hands: Before entering the cleanroom changing area, thoroughly clean your hands with hand sanitizer, then dry them with a clean paper towel or a hand dryer.


Dressing Steps in the Changing Area

Dressing Steps:

Put on Protective Clothing

Inner Protective Garments: If required, start by wearing clean inner protective garments, such as undergarments or long-sleeved shirts and pants. This is usually done in the regular changing area.

Cleanroom Garments: Wear full-body protective clothing designed for cleanroom use, such as coveralls or two-piece suits.

Note: Ensure the protective clothing fully covers your body, and fasten zippers or buttons completely.


Put on Shoe Covers

Cleanroom Shoes or Shoe Covers: Wear cleanroom-specific shoes or shoe covers, ensuring they completely cover your shoes.


Wear a Hood

Wear a Hood

Hood: Put on a hood that covers your hair completely, preventing hair and skin flakes from falling.


Wear a Mask

Mask: Wear a cleanroom-specific non-woven mask or face shield, ensuring your nose and mouth are fully covered.


Wear Gloves

Gloves: Finally, put on powder-free cleanroom gloves, ensuring they fully cover your hands. Double gloves may be used for added protection.


Put on Outer Protective Garments

If necessary, after completing the above steps, put on an outer protective garment, such as a sterile coat.


Entering the Cleanroom

Entering the Cleanroom

Check: Before entering the cleanroom, check for any exposed skin or hair and confirm that all protective gear is worn correctly.

Changing Buffer Area: Enter the cleanroom through the changing buffer area to ensure outside air does not directly enter the clean zone.


Changing Steps:

Remove Gloves

Outer Gloves: If wearing double gloves, first remove the outer gloves to avoid contaminating the inner gloves.

Inner Gloves: When removing the inner gloves, avoid touching the outside of the gloves, handling only the inside.


Remove Protective Clothing

Outer Protective Garments: If wearing an outer protective garment, first remove it and place it in the designated dirty clothes area.

Cleanroom Garments: Then remove the cleanroom garment, being careful to avoid letting the outside surface touch your undergarments.


Remove Shoe Covers

Remove Shoe Covers

Shoe Covers: Remove shoe covers, ensuring the outside surface does not touch the clean area.


Remove Hood

Hood: Remove the hood last, ensuring the outside surface does not touch your hair or face.


Remove Mask

Mask: Remove the mask and discard it in the designated waste container.


Hand Washing and Sanitizing

Clean Hands: Thoroughly clean your hands again with hand sanitizer, then dry them with a clean paper towel or hand dryer.


Important Considerations:

Clean Changing Area:

Maintain cleanliness in the changing area by regularly cleaning and disinfecting it.


Protective Equipment Replacement: 

Regularly check the lifespan of protective equipment and promptly replace any worn or defective items.




Provide regular training to employees on the correct steps and sequence for wearing and changing protective equipment.


Case Study

A large pharmaceutical company operates an ISO 7 cleanroom for the production of sterile injectables. Given the stringent environmental requirements for sterile drug production, any contamination could render the product non-compliant and potentially jeopardize patient health.

To address this, the pharmaceutical company established detailed attire regulations:


Sterile Coveralls: 

Full-body sterile coveralls to prevent contamination from skin, clothing fibers, and skin flakes.


Sterile Gloves: 

Sterile Gloves

Double layers of sterile gloves to ensure complete hand sterility.


Cleanroom Shoes: 

Specialized cleanroom shoes to prevent contaminants from being carried in on the soles.


Hood and Mask: 

Hoods to cover all hair and masks to cover the nose and mouth, preventing contamination from hair and respiratory particles.



To protect the eyes and prevent the emission of particulates from the eyes.




After strictly adhering to these attire regulations, the pharmaceutical company saw a significant improvement in product pass rates. By reducing contamination incidents, product quality was ensured, and production efficiency increased. Regular training sessions for employees on the correct wearing and operating procedures ensured strict compliance with the regulations. The company also conducted regular environmental monitoring to identify and address potential sources of contamination promptly, further ensuring a sterile production environment.



Wearing appropriate protective clothing is crucial for maintaining cleanliness in a cleanroom. By following basic dressing principles, selecting suitable protective gear, and donning it correctly, contaminants can be effectively prevented from entering the cleanroom. This ensures the smooth operation of production and experimental processes within the cleanroom.

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