Definition Of A Cleanroom - Math Problem Example

One can define a cleanroom as an area often used in either science research or manufacturing, that contains a low count of environmental pollutants (which usually include items such as aerosol particles, dust, chemical vapors, and airborne microbes. To be more specific, cleanrooms generally have a controlled amount of contamination that is usually derived or based upon the number of particles per cubic meter at a specified particle size. Cleanrooms do have the capability to be quite large, as some manufacturing companies have entire floors devoted to this concept. Generally, cleanrooms are most popularly used in life sciences, semiconductor manufacturing, and biotechnology (BPA, 2009). According to Engineering Toolbox: "Clean room maintained virtually free of contaminants, such as dust or bacteria, are used in laboratory work and in the production of precision parts for electronic or aerospace equipment. ISO 14644-1, as a clean room expectation, come from the formula Cn = 10N (0.1 / D)2.08 (1) where Cn = maximum permitted number of particles per cubic meter equal to or greater than the specified particle size, rounded to whole number N = is the ISO class number, which must be a multiple of 0.1 and be 9 or less D = is the particle size in micrometers"(2005, par 1). Several items must be taken into consideration when approaching the use of a cleanroom. First, air is an extremely important item to take a close look at. The air that is coming into a cleanroom must be filtered in order to get rid of dust, while at the same time, the air inside the cleanroom must be recirculated through high efficiency particulate air (also known as HEPA) and/or through the use of an ultra low penetration air (ULPA) filter in order to get rid of contaminants that can be created internally. Furthermore, in order to control any other possible contaminants that may enter, those working in the cleanroom must leave through airlocks (which sometimes also forces an air shower), along with protective clothing. Within the cleanroom, the equipment has been made to create minimal air contamination. These include the use of specialized mops and buckets. The furniture that can be found within the cleanroom also gathers a very minimal amount of particles and is easy to clean. However, cleanrooms are not sterile, as much of the attention here is focused on airborne particles. These levels can often be tested through the use of a particle counter (Particle Measuring Systems, 2009). In order to avoid a disruptive air leak, many cleanrooms contain items that keep them at positive pressure. This means that if there are any leaks, the air will leak out of the chamber instead of bringing in any air that might not have been filtered. To further control air, some cleanroom systems will keep humidity to very low levels. This is done often to make sure that there are no electrostatic, or ESD problems. These EST controls are also referred to as ionizers (Clearn Room Forum, n.d.). Cleanrooms are generally given their status based on the number and size of particles allowed per the volume of air. Numbers that are typically larger, like "class 100," are usually referred to by FED-STD-209E, and denote particle number at a size of 0.5um or larger, depending on the cubic foot of air. Smaller numbers refer to ISP 14644-1 standards, and these focus on the decimal logarithm of the number of particles 0.1um or larger permitted per cubic metre of air (Clean Room Certification Standards, 2009). Thus, a class 8 cleanroom has at most 108 = 100,000 particles per m. Cleanrooms in both categories of FS209E and ISO 14644-1 both have log-log relationships that take place concernint particle size and particle concentration. Therefore, a "zero" count in particle concentration is not existent. Because 1 m equals about 35 ft, both standards are mostly equal when measuring 0.5 m particles, although the testing standards differ. Ordinary room air is approximately class 1,000,000 or ISO 9 (Federal Standards, 2009). Class maximum particles/m FED STD 209E equivalent 0.1 m 0.2 m 0.3 m 0.5 m 1 m 5 m ISO 1 10 2 ISO 2 100 24 10 4 ISO 3 1,000 237 102 35 8 Class 1 ISO 4 10,000 2,370 1,020 352 83 Class 10 ISO 5 100,000 23,700 10,200 3,520 832 29 Class 100 ISO 6 1,000,000 237,000 102,000 35,200 8,320 293 Class 1000 ISO 7 352,000 83,200 2,930 Class 10,000 ISO 8 3,520,000 832,000 29,300 Class 100,000 ISO 9 35,200,000 8,320,000 293,000 Room air ISO Class Maximum Number of Particles in Air (particles in each cubic meter equal to or greater than the specified size) Particle size > 0.1 m > 0.2 m > 0.3 m > 0.5 m > 1 m > 5 m ISO Class 1 10 2 ISO Class 2 100 24 10 4 ISO Class 3 1000 237 102 35 8 ISO Class 4 10,000 2,370 1,020 352 83 ISO Class 5 100,000 23,700 10,200 3,520 832 29 ISO Class 6 1,000,000 237,000 102,000 35,200 8,320 293 ISO Class 7 352,000 83,200 2930 ISO Class 8 3,520,000 832,000 29,300 ISO Class 9 35,200,000 8,320,000 293,000 Charts from The Engineering Toolbox, 2005. Once a cleanroom has been made and certified, the daily operation of the cleanroom must be an everyday focus in order to make sure that the items that are made or tested in the cleanroom meet the standards of customer expectations (Clean Room Requirements, n.d.). ISO 14644-5: Cleanrooms and associated controlled environments-Part 5: Operations provides a single source addressing the following six key areas of cleanroom operations: 1. Operational systems 2. Cleanroom clothing 3. Personnel 4. Stationary equipment 5. Materials and portable and mobile equipment 6. Cleanroom cleaning (Dixon, 2007). As far as operational systems are concerned, this focuses on the necessary components that create a guideline in order to make good products while following cleanroom protocall. The focus here is usually on training, standard procedures, safety, and risk assessment. Cleanroom clothing is another important item to consider, as the clothing can protect the product from contamination that employees may otherwise bring in. Furthermore, the clothing can also protect the employees from unwanted interactions. Generally speaking, the largest source of contamination is usually coming in from employees, so the focus on clothing and garments is very important as far as cleanroom procedure is concerned. Personnel accessing the cleanroom must be properly trained and understand the cleanroom operations. Stationary equipment is also important to any cleanroom, and employees must know how and when to clean these items, how to unpack items and put them away, how to install items, and how to correctly remove items from the cleanroom. The transfer of materials and equipment is the next cause of contamination, following that of personnel. Therefore, employees must be aware of how to transfer these items to and from cleanrooms, as well as having the knowledge of how to get rid of waste and properly focus on decontamination. The cleanroom itself must also undergo cleaning and contamination checks in order to make sure it is being efficiently used (Dixon, 2007). References BPA. 2009. "Particle Counters." Retrieved July 19, 2009, from: http://www.particlecounters.org/blog/iso-14644-cleanroom-validating-to-iso-class-8/ Cleanroom Certification Standards 2009. Retrieved July 19, 2009, from: http://www.iprocessmart.com/particlecounters/fs_209e_and_iso_14644_cleanroom.htm Cleanroom Requirements n.d. Retrieved July 19, 2009, from: http://www.vilair-aaf.com.au/Files/ProductDocuments/BulletincleanroomsISOClass7.pdf Cleanroom Forum (n.d.). Retrieved July 19, 2009, from: http://cleanroomforum.com/index.phptopic=367.0 Dixon, Anne Mari. 2007. "ISO 14644-5 Offers a One-stop Guide to Cleanroom Operations." Tech Talk. Retrieved July 18, 2009, from: http://www.iest.org/files/public/TechTalk_ISO_14644-5_Offers_a_One-stop_Guide_to_Cleanroom_Operations.pdf The Engineering Toolbox. 2005. "Cleanroom." Retrieved July 19, 2009, from http://www.engineeringtoolbox.com/clean-rooms-iso-d_933.html Federal Standards. 2009. Cleanroom Standards. Retrieved July 19, 2009, from http://www.set3.com/standards.html Particle Measuring Systems. 2009. Cleanroom Measurements. Retrieved July 19, 2009, from: http://www.pmeasuring.com/moreinfo/ISO14644 Read More