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A Guide to Selecting VAF HEPA Filters for Pharmaceutical Manufacturing

HEPA filters are an essential component for pharmaceutical manufacturing operations. To maximize effectiveness, selecting the right VAF HEPA filter that can capture particles at a high-efficiency rate is important. This guide will provide you with considerations to ensure you choose the right VAF HEPA filter for your needs.

What does a HEPA filter mean and where does it come from?

A HEPA (High-Efficiency Particulate Air) filter is a type of air filter designed to capture airborne particles, such as dust, pollen, mold spores, and even bacteria. HEPA filters are much more efficient than traditional air filters and can capture 99.97% of airborne particulates that are 0.3 micrometers or larger in size. HEPA filters are commonly used in pharmaceutical manufacturing operations to provide contaminant control and ensure product quality.

HEPA filtration technology was first designed and created in the 1940s by the Defense Research Commission and the Chemical Corps of the United States Army. As part of the Manhattan Project, a top-secret government project revolving around the development of the atomic bomb during World War II, scientists were then asked to develop a suitable filter to remove the particles. radioactive material from the air.

In Europe, HEPA filters must remove 99.95% (ISO) of particles. In the US, they must remove 99.97% of particles.


Filtration Rate of MPPS

ISO / European (ISO29463 / EN 1822)

≥ 99.95%

US Standard (MIL-STD-282)

≥ 99.97%

Understand the Necessary Contaminant Protection.

When selecting a HEPA filter, you’ll need to consider the necessary level of protection against airborne contaminants. Each HEPA filter is designed to achieve a specific air purification efficiency, so it is important to choose one that can meet your requirements for the particular application. For instance, the highest efficiency HEPA filters may be used in sterile pharmaceutical manufacturing operations where extremely tight air cleanliness standards must be met.

When following the ISO or European rules, filters that capture ≥85% of particles but less than 99.95% are called ‘EPA filters’ or ‘efficient particulate air filters’. These air filters do not meet the filtration requirement to be considered a ‘HEPA air filter’.

On the other hand, filters that exceed the requirements of a ‘HEPA air filter’ and capture more than 99.999% of particles are called ‘ULPA filters’ or ‘ultra-low penetration air filters’.

99.9995% – 99.999995%


Filtration Rate

EPA (efficient particulate air filter)

85% – 99.5%

HEPA (high-efficiency particulate air filter)

99.95% – 99.995%

ULPA (ultra-low penetration air filter)

99.9995% – 99.999995%

How Do VAF HEPA Filters Work?

Most of us might start out thinking HEPA filters work like a net. And here’s how the three different mechanics work for different particle sizes. Straining and impact capture large particles; interception captures medium particles, and diffusion captures the smallest particles.


The “large” particles fly into a HEPA filter, they’re too big to get through, so they get stuck. When particles get stuck between two fibers, they call it “straining.”

Human hair is about 50µm wide


Let’s look at the next size range down: 0.3 – 1 microns. We’re talking about the size of a bacteria. Particles of this size occupy the space between the fibers in a HEPA filter. They will try to follow the air around the HEPA filter, but they are a bit heavy and the particles don't move fast enough so they will eventually get trapped. Scientists call this an "interception".

Size of coronavirus particle pm2.5 and bacteria


The really small particles (less than 0.3 microns), these particles that small have so little mass that they actually get bounced around like a pinball when they hit gas molecules (that’s called Brownian Motion). So they move in random zigzag patterns.

These particles are so small they could easily fit through HEPA filters, they don’t fly in straight lines. Because they fly in zigzag patterns, they end up hitting the fibers and getting stuck. Scientists call that diffusion.

Particles move in random zigzag patterns

Consider The Construction and Design of the Filters.

When selecting a VAF HEPA filter, it’s important to consider the construction and design of the unit. There are many different types of VAF HEPA filters available and they vary in terms of the type of casing material used and the overall shape and size. For example, large-sized HEPA filters may require additional support structures or brackets to ensure their stability, while smaller units may be easier to mount directly onto walls or ceilings. It’s also important to select a filter that is designed for your application – if you’re looking for a unit to be used in an operating room, then a dedicated operating room grade filter should be chosen.

When selecting a VAF HEPA filter for your pharmaceutical manufacturing facility, you need to take into consideration factors such as size, capacity and how the filter will fit into the existing space. In addition, flexible manufacturing settings can require greater design flexibility in order to accommodate changing production needs. It is important to consider modular and expandable options that can easily be adapted when required. The design of your filter should also factor in key safety features such as enclosures, built-in shut-off valves, spill containment or an auto lock-out/tag-out mechanism.

Examine Efficiency Ratings and Clean Air Delivery Rates (CADR)

When selecting a HEPA filter, it’s important to look at efficiency ratings and clean air delivery rates (CADR). HEPA filters are rated by their efficiency, which is measured in terms of how much of the airborne particulate matter that passes through the filter is actually removed. The CADR rating represents the volume of air being purified by the filter, which should be closely matched to the requirements of your own application. Factors such as room size, ventilation rate, and operating conditions will be key considerations when choosing a suitable unit for your needs.

Let's find out the VAF HEPA filters of VAF™️ - VIET AIR FILTER applied in the pharmaceutical manufacturing industry


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