HVAC system control the cleanroom grade in pharmaceutical industry. Where HEPA filter is an important and integrated part of HVAC system. This article covers following topics -

1. What is a HEPA filter?

2. Why it is important?

3. How do HEPA filters work?

4. HEPA filter efficiency

5. Why used Pre Filter/Primary Filter?

6. Fan filter unit

7. Why Should You Change Air Filters?


1. What is a HEPA filter?

When choosing an air purifier for pharmaceutical industry, the element to look at is clearly the HEPA filter. The quality of the HEPA filter used by the air purifier is key, as it is the most important element in the filtration process, cleaning the air of particles that are harmful to health and releasing clean air.

HEPA filters are the reason why so many air purifiers have been installed during the current pandemic in schools, hospitals and offices, and the reason why air purifiers are useful in improving the quality of life of those who suffer from allergies and asthma.

But what are HEPA filters? How do they work? Why are they so effective against viruses, bacteria, and allergens? Here you will find everything you need to know.

HEPA "(high efficiency particulate air [filter])" is a type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (┬Ám).

 

2. Why it is important?

HEPA (High Efficiency Particulate Air) filters are filters with a great capacity to filter small particles (really tiny ones!). HEPA filters remove more than 99.997% of the particles from the air stream that passes through them. These particles can be allergens, viruses, bacteria, chemical compounds, dust and many more. It’s essential to maintain cleanroom in pharmaceutical industry. 

This is also great help for people with asthma, allergies or those who suffer from respiratory problems. These types of filters are becoming very important during the COVID-19 crisis by helping to reduce the virus indoors, thus reducing the spread of the virus.

 

3. How do HEPA filters work?

The operation of HEPA filter is simple. Air purifiers absorb air, pass the air through a series of filters (including the HEPA filter), and release clean air into the room. The filter is composed of a mesh of randomly placed fibers, which are usually layers of cellulose, synthetic fiber or glass fibers. These fibers are arranged in an accordion shape, which gives them a greater capacity to capture the particles. The HEPA filter easily removes pathogens larger than 0.3 microns.


4. HEPA filter efficiency

To choose between one air purifier or another, you need to know what type of HEPA filter each purifier uses. Therefore, you must start by knowing what percentage of particles the different types of HEPA filters are capable of holding.

Currently it is not possible to achieve 100% filtration, although this technology is very close to it, because a HEPA filter retains 99.997% of the Most Penetrating Particles (MPPS) of 0.12 to 0.25 microns. A HEPA filter is able to do this with the smallest and Most Penetrating Particle Size (MPPS), now imagine how effective they are against particles larger than one micron, which are those particles that viruses tend to have attached to. They are even easier to filter and retain by the HEPA filter. Therefore, the efficiency of a HEPA filter is almost 100%.

There is no more effective air treatment technology at this time.


The 0.3 micron benchmark is used in efficiency ratings, because it approximates the most difficult particle size for a filter to capture. HEPA filters are even more efficient in removing particles that are smaller than 0.3 microns and larger than 0.3 microns. A filter that is 99.97% efficient at 0.3 microns means 99.97% effective at trapping particles at its most vulnerable size of 0.3 microns.


5. Why used Pre Filter/Primary Filter?

As their name suggests, pre filters are responsible for filtering out the particulate in air before it gets to the HEPA or ULPA filters. Generally, these remove larger particles. Using pre-filters is also a great way to extend the life of your HEPA filters, as it makes the HEPA filter work less. 
If your filtration system has pre-filters, it's good practice to change them about 6 times a year, or every other month. This will keep everything in your filtration system running smoothly, and will ensure that none of the cleanroom system parts past the pre-filters experience excessive contamination.

6. Fan filter unit

A fan filter unit (FFU) is a type of motorized air filtering equipment. It is used to supply purified air to cleanrooms, laboratories, medical facilities or microenvironments by removing harmful airborne particles from recirculating air. The units are installed within the system's ceiling or floor grid. Large cleanrooms require a proportionally large number of FFUs, which in some cases may range from several hundred to several thousand. Units often contain their own pre-filter, HEPA filter and internally controllable fan air distribution.

7. Why Should You Change Air Filters?

An HVAC system pushes air through the filter, trapping dirt, dust, pollen, mold and other particles. When left unattended, filters accumulate dirt, and the following can occur:

1. Decreased airflow efficiency.
2. Damage to your cooling or heating equipment.
3. Lower air quality leading to cardiovascular and respiratory health complications and diseases.
4. A higher energy bill. Dirty filters make your HVAC system work harder, increasing your energy bill. For instance, unclogging your A/C can lower your electricity bill by 5 to 15 percent.

All air cleaners require periodic cleaning and filter replacement to function properly.  Follow manufacturer's recommendations on maintenance and replacement.