You are not allowed to bring food, drink, cigarettes, gum or anything else that will give off particles into a cleanroom. Depending upon the cleanroom classification, there are even stricter rules about what you cannot bring in.
1. Food and drink
Figure 1. Person with fast food
Cleanroom personnel are not allowed to eat or drink in the cleanroom. Both activities generate significant particles. Cleanrooms are for work only. Bringing food into a cleanroom also increases the possibility of insects, germ or mold growth from food and drink waste. Often operators in cleanrooms are dealing with toxic chemicals that could hurt operators if accidentally ingested.
2. Chewing gum and chewing tobacco
The act of chewing either gum or tobacco generates particles in a cleanroom. Spitting of chewing tobacco is very messy. In addition, disposing of chewing gum and chewing tobacco is problematic in a cleanroom. Many cleanrooms are supposed to be sterile. Chewing gum or tobacco is very similar to eating and not compatible with sterile protocols.
3. Cigarettes
Figure 2. Pack of cigarettes
Cigarettes when lighted give off smoke and ashes which are significant particle sources. E-cigarettes are source of particles when user exhales. Cigarettes are also a significant fire hazard in a cleanroom. It is recommended that operators wait a minimum of 30 minutes after smoking before entering a cleanroom as they are covered in smoke particles.
4. Paper
Figure 3. Open paper notebook
Normal paper is manufactured from wood pulp and gives off significant particles in a cleanroom. If it necessary to have paper in a cleanroom, companies often purchase cleanroom grade paper which is manufactured with latex coated cotton fibers and is typically colored blue. A less effective option is to keep paper in plastic sleeves and closable note books when not writing. This may be sufficient for lower class ISO-7 and ISO-8 cleanrooms.
5. Pencils
Figure 4. Wooden pencil
Pencils should not be used in cleanrooms since they have graphite core that generates particles during writing. In addition, the act of erasing pencil text creates significant rubber, paper and graphite particles. Mechanical pencils have the same issues and should not be used in cleanrooms. Most people use ink pens when writing in cleanroom. Another option is to use computers or I-pads to record all information inside cleanroom.
6. Cardboard
Figure 5. Brown cardboard box
Cardboard gives off significant particles and should not be taken into cleanrooms. Cardboard is porous and can break down when it gets wet. If wet, it can provide location for growth of bacteria and mold. Often cardboard boxes are covered in dust from shipping, and it is very difficult to clean cardboard boxes. If cardboard boxes must be brought into cleanroom, they should be placed inside cabinets or plastic bins to prevent from being exposed to the cleanroom.
7. Shorts, Skirts, Open-toed Shoes, and Sandals
Any clothes or foot covering that results in exposed skin are not allowed in cleanrooms. Exposed skin is a major source of particulates in cleanrooms. In addition, cleanroom garments such as bunny suits, bouffant, hoods, booties, Tyvek lab jackets, gloves, safety glasses and masks are used to cover the clothes and skin of cleanroom personnel and reduce the number of particles the personnel generate in the cleanroom.
8. Make-up is sometimes forbidden in cleanrooms
In some higher-class cleanrooms, operators are forbidden from wearing makeup. Cosmetic particles can introduce contamination and chemicals into the cleanroom.
Summary
Cleanrooms are designed to be particle free and, in many cases, sterile. Because of this, food and drink, chewing gum, chewing tobacco and cigarettes are not allowed in cleanrooms. In addition: paper, pencils, and cardboard are typically not allowed in cleanrooms.
Finally, certain garments such as shorts, skirts, open toed shoes and sandals are not allowed in cleanrooms because they expose human skin inside the cleanroom. Make-up is sometimes forbidden in cleanrooms depending on the industry and classification of cleanroom.
The author Anthony Chien has worked at American Cleanroom Systems for past 12 years. He has more than 40 years of cleanroom experience. Anthony has a BS and MS in Electrical Engineering specializing in semiconductor manufacturing from the University of Illinois.
American Cleanroom Systems is a design build modular cleanroom manufacturer based in Rancho Santa Margarita CA. It is expert in ISO-5 through ISO-8 (class 100 to class 100k) modular cleanrooms for pharmaceutical cleanrooms, medical device cleanrooms, and industrial cleanrooms.
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