FanAir Company – Design / Build Clean Room Filtration System:
Challenge: Design a clean room divided into three class 10,000 areas. The class number refers to the maximum number of particles 0.5μm in diameter allowed in one cubic foot of clean room air. The clean room is equipped with state-of-the-art high-resolution e-beam, photo and nano imprint lithography equipment.
LCD Displays run at 1080p 1920 x 1080 Full HD resolution, with 178-degree horizontal and vertical viewing angles. It has a 2,000:1 contrast ratio, a brightness of 300 cd/m2 and an 8ms response time. All components must be free of any lint, dirt, dust or contamination.
FanAir Co has designed a system array of filtered supply and exhaust return blowers to remove nearly 100% of any contamination. down to 99.97% of all Particles down to .3 Microns on Size.
The US standard (DOE-STD-3020-2005) requires that a HEPA filter be capable of removing 99.97% of contaminant particles 0.3 μm in diameter. Most standards also specify that HEPA filters must feature minimal pressure drop and maximum airflow when in operation.
A filter’s percent efficiency can be calculated using the simple equation below.
E = percent efficiency
D = downstream concentration (of contaminants)
U = upstream concentration (of contaminants)
Particle Size and Filtration Method
While the US HEPA standard usage of 0.3 micrometer particles to describe efficiency may seem arbitrary, particles of this size are actually the most difficult to filter, rendering them a kind of “worst-case scenario” reference particle. The reasons for this difficulty in filtration are described below.
HEPA filter media is made up of countless randomly-arranged fibers which together form a dense mat; when air flows through the filter, the media captures and contains contaminant particles throughout its depth.
by Scott Sneller 02-27-2018