When it comes to air filtration, two of the most popular options are HEPA and ULPA filters. While both are effective in trapping particles, they have different levels of efficiency and are used for different applications. HEPA filters are known for their superior performance in removing particles from the air. They have an efficiency of 99.97 percent in trapping particles that are 0.3 microns or larger in diameter.
This makes them a great choice for general air purification, as they can effectively remove most particles from the air. Replacing the filter is all that is needed to ensure its performance. ULPA filters, on the other hand, are more effective in trapping particles that are smaller than 0.12 microns in diameter. They require 99.99% efficiency with a target particle size of 0.1 microns and have a dense network of fibers arranged randomly.
This makes them ideal for specialized applications such as microelectronics manufacturing or medical laboratories, where they can be used to remove particles from clean rooms or filter toxic surgical columns emitted during electrosurgical operations. Traditional air filters, except those with a lower efficiency index, also filter small particles from the air. However, HEPA filters offer a better way to reduce larger particles and are far more effective than a simple sieve in trapping both small and large particles. Designing a ULPA system that supplies the same ACH as a HEPA system would require a larger filter to compensate for the more restrictive flow and, possibly, a more powerful fan, making the entire filter system larger and more expensive. It is important to follow infection control precautions described in the ICRA matrix when using ULPA filters, such as correctly installing temporary barriers, creating a negative air environment with HEPA-equipped filtration machines, and cleaning with vacuum cleaners with a HEPA filter.
