Monday, September 9, 2019
ISO 14644 FOR AN IAP CLEAN ROOM CLASS 8 IN RESPECT OF 0.5 UM PARTICLES Essay
ISO 14644 FOR AN IAP CLEAN ROOM CLASS 8 IN RESPECT OF 0.5 UM PARTICLES - Essay Example 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. How ever, 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 I SO 9 (Federal Standards, 2009).