ULPA vs HEPA
It is a bit difficult to imagine that in the not too distant past, clean air wasn’t common in standard places like doctor’s offices, distilleries, hospitals, factories, etc. Before the invention of commercial filtration of air, workers were exposed to hazardous indoor air pollution (IAP). Moreover, they could experience illnesses from pollution such as cancer, blood poisoning, asthma, and other common diseases.
Eventually, Ultra-Low Particulate Air (ULPA), and High-Efficiency Particulate Air (HEPA), came along and addressed many of the needs. Both are commonly used today and often employed in sales and marketing materials as key differentiators, leading to an ULPA and HEPA battle in technical specifications.
ULPA and HEPA as Pollution Solutions
Indoor air pollution usually carries pollen, mold spores, dust mites, etc., leading to health issues in people who might suffer from asthma or allergies. Moreover, in typical commercial environments like factories, air pollution may also damage equipment. Thus, high efficiency and effective air filter media are useful in maintaining a safe environment for people working and in mitigating cross-contamination.
Ultra-Low Particulate Air (ULPA), and High-Efficiency Particulate Air (HEPA), are the most ordinary types of filters utilized in hospitals, clean rooms, semiconductor, pharmaceutical, and biomedical manufacturing, as well as in homes.
ULPA vs HEPA - The Similarities
It is noteworthy that both ULPA and HEPA are curated from glass fibers and then spun, hooked, and later rolled into paper-like materials. Later they are pleated, which leads to an increase in the surface area of the filters.
Typically, ULPA filters and HEPA filters are designed to trap the smallest particulate contaminants from air streams via forcing air through a fine mesh-like media. Since they are curated from fiberglass and arranged randomly, this results in the formation of a dense mat or filter media.
There’s a combination of various methods for trapping particulates in the air. These three methods are:
- Inertial impaction - due to inertia particles from .5 to 5 microns in diameter deviate from an air stream and are caught when they impact filter fibers and stay in place by cohesion with the filter
- Interception - particles from .1 to .5 microns are small and light enough to continue moving in the air stream around the filters and are intercepted when they contact the fiber
- Diffusion - very small particles (below .1 microns) bounce around and move in zigzag patterns known as Brownian motion. So, given this effect, very small particles can be captured by ULPA and possibly even HEPA filters.
However, neither ULPA or HEPA air filters can remove odors or gasses. Should you want to address those concerns in your environment, it is best to utilize other technologies such as carbon filters for such purposes.
In short, here are some core similarities between ULPA and HEPA air filters
- The filter making process
- The filter construction
- Neither can remove odors and gases
- Used in same type of environments to address common concerns
ULPA vs HEPA - The Differences
Now having discussed the similarities, lets look at the differences between the two. As mentioned earlier, both are designed to remove small particulates (which means they also work for larger particles). However, to increase the performance, durability, and efficiency of these air filters for long-term use, pre-filters are put in place to remove the larger particulate leaving ULPA and HEPA to do what they do best.
With respect to ULPA vs HEPA, the key difference lies in how efficient these filters are in removing the small particulate contaminants.
HEPA filters remove airborne particles at sizes down to 0.3 microns in diameter at 99.95 to 99.99% efficiency.
ULPA filters remove airborne contaminants at sizes below 0.1 microns in diameter at a 99.9975-99.9999% efficiency.
ULPA vs HEPA - Filter Applications
ULPA and HEPA filters are both effective in mitigating the spread of cross-contamination, infection, and allergens that are airborne in residential and commercial environments.
Additionally, these filters can be utilized in various applications including laboratory equipment, the biomedical industry, pharmaceuticals, semiconductors, etc. In these environments, the air purification filters are crucial for maintaining clean and pure air.
HEPA filters are typically used in government, military, and industrial applications. They are also popular in various manufacturing environments where the control of airborne particulate is important. The popularity of HEPA is continually growing and has become common for home use.
On the other hand, ULPA filtration is usually found where there are higher needs for mitigating airborne bacteria and viral pathogens from spreading. ULPA filters are best suited in critical applications like the aerospace industry, electronics, clean rooms, cabin cleaners, biomedical labs, etc.
ULPA vs HEPA in Air Purifiers
HEPA is the popular choice in air purifiers. In fact, manufacturers will actually feature different types of HEPA such as Medical, True, and Super. One of major reasons is the restriction of air flow in ULPA filters, which impacts CFM, CADR, and ACH.
Given 99.97% efficiency at .3 microns, many air purifier manufacturers believe that HEPA filters are sufficient given the beneficial effects of Brownian motion, and would rather tradeoff the decimal points for more air exchanges per hour and more coverage area.
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These air purification systems typically use a pre-filter to capture larger particles (like a human hair) giving longer life to the HEPA Filter which removes smaller particles (like mold spores).
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