Cleanroom clothing: regulations in the clean environment

Personnel clothing can make a significant contribution to maintaining the cleanliness of the clean environment. Ensuring the air cleanliness class in the cleanroom therefore depends above all on the right cleanroom clothing. Only if it fulfils the strict regulations of the cleanroom the processes, machines and the cleanroom itself can be protected from unnecessary contamination by personnel. In this blog post, we look at the importance of cleanroom garments, what functions they should ideally fulfil and the advantages and disadvantages of disposable and reusable clothing.

Unfortunately, the factor of humans is one of the main causes of contamination in the clean working environment. Particles caused by people, such as dust, skin particles or hair, contribute up to 40 per cent of contamination. If cleanroom personnel are not equipped with appropriate protective clothing, these particles can enter the cleanroom unhindered and lead to contamination. The right cleanroom clothing is therefore essential to protect the clean production environment from such unnecessary contamination and to ensure process and product quality. 

Importance of the dress code in the cleanroom

Cleanroom clothing generally refers to all work clothing that is adapted to the special requirements of working in cleanrooms and clean areas. Due to the special process and production specifics and the specifications regarding the air cleanliness class of the cleanroom in accordance with the ISO standard, this is subject to significantly higher requirements than normal workwear. Depending on the intended use and work processes, however, the requirements of the various cleanroom garments can also differ from each other.

Cleanroom clothing is therefore of particular importance. On the one hand, the right workwear in the cleanroom protects products and processes from contamination by personnel, but on the other hand, the cleanroom clothing itself can also contribute to a possible release of particles and thus contamination. If the clothing is worn or damaged, for example, particles can detach from the material and enter the clean environment. However, cleanroom garments of inferior quality can also be a significant factor in the contamination of the room. 

Find out everything you need to know about cleanroom technology here.

Cleanroom clothing ideally fulfils the following functions

• Filter between the human particle source and the cleanroom: The cleanroom clothing fulfils primarily a kind of filter function between the personnel, and the associated particle releases, and the corresponding cleanroom. The so-called particle retention capacity of workwear depends primarily on the composition and porosity of the material. These properties of the clothing are associated with both positive and negative effects. The lower the porosity of the fabric, the better the particle retention capacity. However, a high particle retention capacity, which is usually due to a denser fabric, often means that the garment is less comfortable to wear. High-quality cleanroom clothing combines particle retention capacity with a high level of wearer comfort.
• Particle migration: When wearing cleanroom clothing, friction occurs between the surface of the employee's body and the inside of the cleanroom clothing. Friction can cause particles and fibres to be released mechanically and released into the cleanroom environment through the textiles. High-quality cleanroom fabric retains released particles and fibres so that they are not released into the clean environment when worn.

• Resistance to abrasion: The outside of the cleanroom clothing can also lead to additional particle and fibre contamination of the cleanroom. Particles can also be released into the cleanroom every time the garment is worn. The abrasion resistance of the fabric is therefore particularly important. If worn several times over several days, the clothing may already be contaminated to such an extent that these contaminants are released back into the environment.
• Material: Fabrics made of purely synthetic fibres (e.g. polyester) are much more suitable for cleanroom clothing than fabrics made of natural fibres or blended fabrics due to their higher abrasion resistance.

• Electrostatic: Although synthetic fibres offer better protection against unnecessary abrasion of the fabric, they are accompanied by another negative effect: electrostatics. Even motion sequences with normal movement intensity can lead to electrostatic charges, which can act like a magnet on whirling particles. The accumulated particles can, for example, get onto the highly sensitive products and machines through air currents and thus contribute to contamination. For this reason, many cleanroom clothing systems have antistatic properties.

• Decontamination capability: If reusable clothing is used, it must be professionally decontaminated after each usage cycle. Effective decontamination of cleanroom clothing is the only way to ensure that no contaminants from the previous wear cycle are passed on. In addition to the textile fabric itself, the respective processing of the textile also has a major influence on its ability to be decontaminated by the cleaning process. For example, cleanroom garments with pockets are not recommended as they make decontamination much more difficult. But even reusable cleanroom clothing cannot be cleaned an infinite number of times. After a certain number of wear cycles, the cleanroom clothing should be replaced with new textiles, as the more frequently used clothing will show higher fibre breakage over time and therefore the best possible protection of the cleanroom environment can no longer be guaranteed.
  
  

Cleanroom clothing: disposable or reusable?

Cleanroom clothing is available on the market in two alternatives. Either as a disposable or as a reusable system.

In the case of disposable clothing, it is packaged immediately after production and made available to the respective recipient for use. As the name suggests, the disposable garments are disposed of after being worn once and new clothing is put on the next time they enter the cleanroom.

Reusable clothing can survive several wear cycles before it is disposed of professionally. Overall, it is more complex to manufacture than disposable clothing and can be reused up to 150 times. With reusable clothing, the decontamination process is crucial for maintaining the cleanliness quality of the room. After the cleanroom clothing has been worn, it is washed in the decontamination process and any particles are removed. After cleaning, the reusable garments are packed in the cleanroom with a low particle content and made available for reuse.

Disposable clothing is often a necessary supplement to reusable clothing. It is primarily issued to visitors and external service personnel.

The right cleanroom clothing and the correct way to wear it therefore make a significant contribution to maintaining the air purity quality of the cleanroom. Not only the cleanroom is significantly protected from contamination by the right clothing, but the personnel are also protected by the clothing. Cleanroom clothing must fulfil a wide variety of functions in order to meet the special requirements of the cleanroom. 

The operator of the cleanroom or clean area is responsible for providing the cleanroom clothing. Cleanroom clothing brought in, e.g. by external service personnel, is not permitted.

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