How Do Staff Members Become Sources of Contamination in Cleanrooms?

It is essential in a cleanroom environment to keep airborne particles, bacteria, and chemical contaminants under control. Nevertheless, workers themselves are potentially the biggest source of contamination in a cleanroom. Most of the particles that contaminate cleanrooms are brought in by people working in and coming and going from the facility. How does garbage end up in the water, and how can we avoid this problem?

Why do personnel become sources of contamination in cleanrooms?

The human body is a complex particle generator. Even in a still environment with no movement, the skin continuously sheds microscopic flakes through metabolism. Breathing and speaking also release large amounts of bacteria and particles. When personnel move around, walk, wear improper attire, or violate operating procedures, the risk of contamination increases sharply.  

For example:  

• Skin flakes and hair shedding

• Static electricity generated by clothing friction attracting dust

• Breathing and speaking releasing bacteria and water vapour particles

• Frequent entry and exit introducing external contamination

Without a reasonable Cleanroom Design that standardises personnel entry and exit, attire, and air purification, the cleanroom environment can easily become uncontrolled, directly affecting product quality.

What methods can be used to prevent personnel contamination?

1. Strict entry and exit management system

Before entering the cleanroom, a buffer zone and Air Shower Room must be set up. Through powerful clean airflow, particles on the human body and clothing are blown off, reducing the risk of carrying contaminants into the clean environment. Installing a high-quality air shower room can effectively reduce over 90% of adhering dust particles, making it a standard facility in modern cleanrooms.

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2. Rational cleanroom design

The airflow velocity, direction, and pressure differential design within the cleanroom directly affect the dispersion and removal of contaminants. A scientifically sound cleanroom design ensures that airflow moves downward in a unidirectional manner, carrying particles away and preventing the accumulation of contaminants indoors.

Additionally, cleanrooms should minimise personnel movement, cross-operations, talking, and unnecessary activities, ensuring designated personnel for each position and standardised processes to further reduce human-caused contamination sources.

3. Strict Wear and Use Regulations

Standardised cleanroom suits, hats, masks, and gloves are basic measures to prevent the spread of human particles. When wearing them, follow the proper sequence to avoid secondary contamination. For example:

• Wash hands and wear a mask before putting on a cleanroom suit

• Put on shoe covers and anti-static shoes

• Put on gloves and a head cover, then put on the cleanroom suit

These items should be regularly replaced and cleaned to maintain their effectiveness.

4. Install high-efficiency purification equipment

High-efficiency air purification equipment can continuously purify airborne particles, maintaining air cleanliness. In particular, the Fan Filter Unit(FFU) is one of the core purification devices in a cleanroom. It uses built-in high-efficiency filters and silent fans to continuously supply clean airflow to the work area, ensuring the air remains under positive pressure and preventing contaminants from backflowing.

Understanding the application principles of FFU Fan Filter Units can help you learn more about FFU products.

Summary

That said, even though cleanrooms look protected from outside contamination, staff members coming in and out can still introduce unwanted substances. To maintain cleanliness and ensure the quality of products, we must stick to planned procedures for all entry, exit, and cleaning standard operations.