MERV Air Filter Rating | Industrial Air Filtration

While home air purification is a fairly modern practice, using air cleaning equipment to maintain healthy indoor air quality (IAQ) has been taking place for nearly half a century in the commercial sector. Auto shops, hair salons, hospitals, dental offices, and other businesses like hotels, airline carriers, laboratories, and manufacturers, have all benefited from indoor air pollution removal products.

But businesses just beginning to look into industrial air filtration may not know where to start. A good place to begin is establishing the contaminant that needs to be eliminated. The next step is determining the recommended MERV air filter rating needed to effectively capture that particulate.

MERV Rating Defined

MERV is an acronym that stands for Minimum Efficiency Reporting Value. The rating ranges from 1 -20. This system was developed to measure a filter’s ability to remove airborne particles that pass through it. This rating system aims to help someone choose between the different filters available.

Under MERV, the higher the rating, the smaller the particle the filter can collect. The lower the rating, the more appropriate that filter is for capturing larger contaminants.

Micron Sizing

Airborne particles are generally defined by the metric unit of measurement called a micron. A micron particle size is one-millionth of a meter which is also one twenty-five thousandth of an inch: 1/1000 mm = 1/25,000 inch. The average person can see airborne particles that are around 40 microns or larger. To understand this, consider that fine flour dust may be as large as 10 microns but still be imperceptible to the human eye and a strand of fine cat hair may measure 40 microns and a grain of salt 60. Pollen dust ranges from 1 to 500 and specks of sand from 20 to 1500. Viruses, however, fall between .005 to .1. Which filter a company needs will depend entirely on the particle that needs to be filtered from a worker’s breathing space.

MERV Rated Filtration

All commercial filters go through rigorous testing to determine their MERV air filter rating by their minimum efficiency. A business should determine its industrial air filtration needs based on the type of contaminants it wishes to remove, in addition to the size, measurement, and airflow of the area of pollutant emissions. MERV air filter ratings are based on particle sizes are generalized below.

MERV Rating 2-4 are filters suitable for commercial settings that need to eliminate contaminants such as textile and sawdust, fiberglass insulation, mists, dust mites, and pollen measuring a minimum of 10 microns.

MERV 5-8 rated filters are ideal for commercial and industrial workplaces and can capture MERV 2-4 plus mold, asphalt paving, many bacteria, and other contaminants between 3 – 10 microns.

MERV 9-12 filters are suitable for medical facilities, commercial, and industrial settings. Will capture particles MERV 2-8 plus finer particle dust, bacteria, and fumes between 1-3 in particle size.

MERV 13-16 satisfies filtration needs in locations such as hospital patient rooms, smoking lounges, and vet clinics. These filters will capture all of the above plus most smoke, ash, pet dander, and droplets from the average sneeze. Particle size from .3 to 1.0.

MERV 17 – 20 filters are the highest rated filters because the micron sizes are so small, measuring less than .3. These filters capture most of the same pollutants as all the other filters plus most viruses, odors, allergens, and radon.

How to Choose Your Filter

Based on MERV, one might assume that the best filter would be one with the highest rating since they capture the most particles. But it doesn’t really work that way.

Take ULPA filters (MERV 19-20), for example. Made to collect the smallest particulate, their use makes sense only for settings such as pharmaceutical labs and cleanrooms. ULPA filters are the densest media and restrict airflow to levels that would be unacceptable in certain situations. Plus, they cost more and have a shorter lifespan than other filters. So only when collecting the smallest of particles is critical to your business would you wish to purchase this filter.

On the other hand, HEPA filters (MERV 17-20) also collect small particulate but have a broader range of micron capture making them ideal for healthcare settings where viruses (.3 microns) can travel on larger particles such as the saliva from a human cough.

In manufacturing, however, the type of filtration you need depends largely on what you are producing. Sawmills will need different filters than coffee roasting plants. Distilleries will have filtration needs vastly different than a facility that manufactures plastic bottles.
So which filter is best? HEPA, pleated, ionic, fiberglass, ULPA? Once you know what impurities you wish to remove, the best way to determine your industrial air filtration needs is to contact an indoor air quality specialist. At AIRSInc., we pride ourselves on our 40 years of stellar air cleaning service. Contact us today for a FREE air filtration evaluation.