Air Purification

Important Facts About Air Filters and Filtration

Aeroex is continuing our campaign to arm you with facts about air purification! You can use the same information we use to design our purification systems to understand the types of filters companies offer and the underlying filtration technology used.

Filter Type and Filter Depth

In our last blog, we discussed what air purification is and the importance of not just looking at filter efficiency but also the capacity of filtering a sufficient volume of air to achieve your target number of air exchanges. Another important factor in air purification performance is the filter depth and material.

 

Previously, we explained the HEPA industry standard. HEPA certifies a filter as being capable of capturing 99.97% of 0.3 micron particles, usually achieved through a series of randomly aligned fibers. Unfortunately, the HEPA standard only certifies the ability of a filter to perform this filtration under ideal conditions and does not certify the long-term performance of the filter. This leads to filters that technically meet the HEPA standard but not your expectations for performance. The common distinction for systems are whether they use depth filters or membrane filters.

Comparing Depth Filters and Membrane Filters

While depth filters and membrane filters can both be HEPA certified, they do not operate the same. Membrane filters are thin but intricate, stopping nearly all particles above the uniform filter size. Unfortunately, they also clog easily because only a small amount of filter media is available. Conversely, a depth-loading filter has a much “thicker” interface for contaminant particles, creating more filtration opportunities. The nature of depth loading means this does not clog the filter and impede performance.

 

Source: G.J. Curiel, H.L.M. Lelieveld, in Encyclopedia of Food Microbiology

Don’t Get Stuck With Cheap Pleated Filters!

Membrane filters in other industries have many essential uses but in air purification, membrane filters tend to be cheap pleated HEPA filters that clog easily. So, it is common to see claims about the performance of the HEPA standard that ignore how often these filters need to be replaced. It is for this reason that Aeroex instead uses a depth-loading filter along with multi-stage filtration – so that when you pay for a HEPA filter, you are using its true purpose of only removing the smallest particles. 

 

When you see a discussion of HEPA filters, remember the information shared by Aeroex and other trusted sources! If you ever have questions about the science of air purification, do not hesitate to contact Aeroex.