Cleanrooms are vital for industries that process extremely delicate materials that can be compromised by airborne particles. Vaccines and microelectronics are only two types of products that benefit from the sterile environment of a well-managed cleanroom. But although it’s not difficult to grasp the manufacturing benefits of cleanrooms, keeping airborne contaminants below an acceptable threshold is always easier said than done.
Not all cleanrooms have identical requirements when it comes to minimizing contamination. For instance, the requirements of an ISO 3 cleanroom are more strict than those of an ISO 7 facility. Nonetheless, the same broad purification principles tend to apply to all cleanrooms.
In the tightly controlled environment of a cleanroom, contaminants can arise from a wide variety of sources—including some that are easily overlooked by people who are not accustomed to the stringent maintenance demands of these areas. Understanding where contaminants come from is key to controlling them properly. With that in mind, let’s have a look at the most common sources of contamination in the cleanroom.
By far the most common source of contamination in a cleanroom is the human personnel inside it. In fact, human beings account for over 80% of the contaminants found in these areas.1 Much of this contamination happens without any effort on our part, as we typically shed about one billion skin cells every day.2
When we’re in motion—e.g., walking from one place to another, or simply gesturing with our hands—the rate of shedding increases exponentially. Talking also expels a substantial amount of potentially harmful particles into the air.
If an employee is ill, their contamination risk skyrockets. Shedding skin disorders such as dandruff, eczema, and psoriasis are particularly troublesome for cleanrooms.
Cosmetics, deodorants, perfumes, and lotions also contribute significantly to the presence of particles in the air. For that reason, technicians are usually discouraged from using products of this nature if these workers are to be inside a cleanroom for any length of time. Another big cause of cleanroom contamination is the clothing worn by personnel. Fabrics that are prone to linting create a hazard in these highly sensitive environments.
It goes without saying that a cleanroom should be kept clean. However, the process of ridding the area of dirt and other contaminants can easily introduce other pollutants into the environment. Actually, this is a major source of contamination in a clean room.
All cleaning products should be approved for use in cleanrooms; normal consumer accessories aren’t suitable for the purpose. This means using mops and cleaning wipes with non-particulating properties. Liquid solvents need to be cleanroom-friendly as well—they should not leave behind residues that might contaminate the area.
Cleanroom technicians are often tempted to bring their own pencils or pens into the area. The problem with this practice is that these seemingly harmless objects can introduce bacteria into the cleanroom. For example, marker pens sometimes harbor molds, which can spread into the air. That’s why many cleanrooms mandate the use of electronic recording devices that never leave the facility.
The kinds of equipment used to aid in the processing of cleanroom products can contribute to the amount of contaminants in the air. Some generate gasses or expel other types of particles that can cause contamination. Furthermore, equipment that vibrates during use tends to throw particles into the air. These are all considerations that should be kept in mind before bringing a particular piece of machinery into the cleanroom.
This is an especially dangerous hazard for cleanrooms that process sensitive electronics. Flooring, wall panels, furniture, work surfaces, and clothing are all capable of generating static that can harm delicate electronic parts. In some cleanrooms, a sudden spark can even trigger a potentially deadly fire or explosion.
The foregoing is not a comprehensive list of cleanroom contaminants, but it covers the most common dangers to these environments. Carefully analyzing all the potential contamination threats in a cleanroom is essential for preventing serious problems from arising.
Tips for Preventing Cleanroom Contamination
Fortunately, there are a number of proven methods for minimizing the risk of product contamination in a cleanroom. These include:
Use high-quality cleanroom uniforms
This may be the number-one strategy for keeping your cleanroom safe. Renting or purchasing cleanroom uniforms from a trusted third-party supplier can go a long way toward reducing pollutants in your facility. Made of breathable, non-linting, ESD materials, cleanroom uniforms sharply reduce the amount of bodily contaminants released into the air and the hazards generated by clothing.
Teach proper gowning procedures
Personnel should be aware of the correct way to don uniforms in order to avoid contaminating the fabric. They should also have access to a dedicated dressing room.
Install anti-static and static-dissipative materials
Ensuring that your floor panels, furniture, work stations, etc., are made from these kinds of materials will lower the risk posed by static electricity.
Install ULPA or HEPA filters
HEPA (High Efficiency Particulate Air) filters remove 99.97% of airborne particles in your cleanroom, while ULPA (Ultra Low Particulate Air) filters extract 99.999% of particles. Both types can severely cut down the concentration of particulate matter circulating through your facility.
Be careful introducing items into the cleanroom
It’s a good idea to ban personnel from bringing non-essential accessories into the facility, as these can easily spread contaminants. New equipment that is to be installed in the cleanroom should be carefully unwrapped, inspected, and cleaned before it is put into use.
Prudential Cleanroom Services (PCS) offers a selection of cleanroom uniforms for rental or purchase. Feel free to have a look through our online catalog to learn more about these products.