HVAC air filter

The Minimum Efficiency Reporting Value, or MERV for short, is an industry rating to determine the effectiveness of air filters. Commonly used to the specify the filtration efficiency  of commercial grade filters, the industry standard rating system allows facility managers to compare different HVAC filters as per their MERV values and choose the one that meets their filtration requirements. To help, here is a summary of MERV ratings according to particle size.

The MERV Rating Chart

MERV Minimum Particle Size Typical Controlled Contaminant
1-4 > 10.0 μm Pollen, dust mites, cockroach debris, sanding dust, spray paint dust, textile fibers, carpet fibers
5–8 10.0–3.0 μm Mold, spores, dust mite debris, cat and dog dander, hair spray, fabric protector, dusting aids, pudding mix
9–12 3.0–1.0 μm Legionella, Humidifier dust, Lead dust, Milled flour, Auto emission particulates, Nebulizer droplets
13–16 1.0–0.3 μm Bacteria, droplet nuclei (sneeze), cooking oil, most smoke and insecticide dust, most face powder, most paint pigments
17–20 < 0.3 μm Virus, carbon dust, sea salt, smoke

MERV ratings usually range between 1-16, but the upper limit has been extended to 20. The MERV rating scale is designed to represent worst-case performance of an air filter that is used for filter particles ranging from 0.3 to 10 micrometers. While the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) recommends using air filters with MERV value 6 or higher, the US Department of Energy recommends products with MERV 13 and LEED recommends filters with at least MERV value 8.

How is the MERV Rating of Air Filter Determined?

Determining the MERV rating of an air filter involves a series of tests. The process includes:

  • Test particles are added into the air in the testing area. These particles are of different sizes and fall into 1 of the 12 categories.
  • The air is passed through the filter that is tested. The density of the particles in the air is measured both before and after the air passed through the filters to determine its efficiency in order to remove the pollutants.
  • The entire process is carried out six times to get six ratings for the twelve categories each.
  • The MERV rating is given on the basis of the worst result.

The Significance of MERV Rating

Maintaining the Indoor air quality is very critical especially in healthcare facilities, pharmaceutical units and several other manufacturing units. The MERV rating assists these facilities to select an ideal filter that removes the impurities from air efficiently. Installing a filter with an MERV rating lower than required may lead to health problems in the facility as the indoor air quality is not clean. Here are the details of which MERV ratings that are ideal for specific sectors:

MERV 1-4

Air filters with MERV 1-4 ratings are recommended for facilities that require minimum filtration. These are used exclusively in residential buildings.

MERV 5-8

Air filters with MERV 5-8 ratings are recommended for residential, commercial and industrial workspaces.

MERV 9-12

Air filters with MERV 9-12 ratings are recommended for residential, commercial facilities and hospital laboratories.

MERV 13-16

Air filters with MERV 13-16 ratings are ideal to be used in hospitals and general surgery units.

MERV 17-20

Air filters with MERV 17-20 ratings are ideal for electronics and pharmaceutical manufacturing units.


MERV rating of a filter is determined through rigorous testing and it gives the performance of a filter in worst-case scenario, which makes it a reliable criteria for air filter selection. It is however essential for commercial establishments and industrial units to understand that highest MERV unit is just one selection criteria. There is a need to pay attention to other factors such as the size of the unit, price factor and the nature of filtration, when choosing an air filter.

Merv 13 Air filter

High efficiency HVAC filters are used by businesses to not only provide a cleaner and healthier environment to the occupants, but also to protect equipment, processes and fixtures. Efficient HVAC filters shield against bioterrorism – one of the reasons why many establishments move air filtration to the forefront of their operating prerequisites. While facility managers are either upgrading their air filtration levels or moving to a new one, there are many others who are unable to unaware of the finer lines of air filtration, such as air pressure drop, and therefore, find it a challenge to select the right one for their needs.

What is Air Pressure Drop?
Air filters are inserted directly into the airflow path of the HVAC system to trap particles flowing through the system. If the air filter is dense and tightly knit, it may trap more particles and this is how the MERV of the filter is also calculated. A filter with high MERV or filtration density often slows down the airflow rate of the HVAC system which is called the air pressure drop.

How Does It Affect Filter Efficiency?
Higher Electricity Consumption
If a facility uses a highly efficient filter such as MERV 13 filter, it may result in higher energy consumption. When a system has a high air pressure drop, the HVAC unit needs to work harder, and therefore, may eventually end up consuming more electricity.

Filter Gets Dirty
The pressure drop created by air filters increases as the filters get dirty. Dust build-up provides less space to the air to flow through the filters and as a result the filters require frequent clean-up.

How to Go About Choosing a Filter?
Let’s look at how to find out whether a filter has a high pressure drop and whether it needs more surface area.
The pressure drop reading of a filter must not exceed the 20% of the maximum static pressure rated for the fan. The rating is present on the data plate of the HVAC equipment. If a fan, for instance, has a maximum static pressure rating of .25 inches, multiply it with .20 to get the ideal pressure drop. The pressure drop of the filter,in the example mentioned above need not be more than 0.05 inches of water column.

There may be instances when you may wonder why is it recommended to buy a high rated MERV filter if it lowers the efficiency of the system? It is important to understand that the problem doesn’t lie only with the filter. The amount of surface area of the filter and the size of the opening of the filter rack play a significant role in determining the pressure drop.
All the filters are not created equal and so even two filters with same MERV rating might have different pressure drops. Pleated filters, for instance, have a high MERV rating but a lower pressure drop than the other types of air filters. A restrictive air filter, on the other hand, has a high pressure drop has the potential to turn a 14 SEER system into an 8 SEER system. When choosing an HVAC system air filter, facility managers need to pay attention to the air pressure drop of the filter, MERV rating and the type of filtration application for which it will be used.
If you have any questions or need expert advice to select the best suitable air filter for your HVAC unit, feel free to speak with one of our representatives.

Torit Powercore Dust Collectors

The development and use of new technologies in industrial and commercial processes has resulted in an increase in the production of smoke, fumes, and dust that are very harmful, especially the contaminants produced during thermal cutting. The Occupational Safety and Health Administration (OSHA) has set permissible exposure limits on manganese and hexavalent chromium. Though the permissible exposure limit of dusts such as a manganese was lowered by OSHA, EPA continues to focus on the reduction of particulates of 2.5 microns and smaller, making it essential for industrial establishments to use an advanced dust collection system.

The Solution: Torit PowerCore Dust Collector
The Torit PowerCore TG Series collector packages progressive dust and fume collection technology, ideal for facilities involved in thermal spray, laser cutting, welding and plasma cutting applications. Its all-welded housing is easy to integrate into an OEM design or fit as a stand-alone on the floor. The Torit PowerCore Dust Collectors TG Series has up to 65 percent smaller footprint than most of the cartridge collectors. In short, it is smaller, smarter, more effective and efficient than traditional 8-cartridge filter collectors.

Highlights of the Torit PowerCore Dust Collector TG Series
Here are some smart features that give the PowerCore TG an edge over other models:
One PowerCore filter pack is equivalent to up to three traditional cartridge filters
Filter with a high MERV rating of 13
A completely assembled and pre-wired device

Use of Leading Technology
The PowerCore filter packs use a technology that is flame-retardant, Ultra-Web nanofiber technology and Donaldson’s media configuration expertise. When the dirty air enters the open flute, it is forced to pass through the media to the adjacent flute. The flute on the opposite side of the filter is sealed and the filtered air exits through the opening on the clean side of the filter pack.

Better Filter Cleaning
The ZERO-Turn PowerPulse Cleaning technology ensures that maximum cleaning energy is delivered in the straight-line paths through the media and the dust is easily pulsed out of the fluted channels.

Downward Airflow
An EPA-sponsored research reveals that the downward flow of dirty airstream in the PowerCore dust collector results in a superior performance, as it reduces the re-deposition of the dust on the filter packs.

Quiet Fan Packs
The Torit PowerCore Dust Collector uses high-performance fans at the base to reduce the noise produced during operation.

Extra Safety Features
The PowerCore TG range has reinforced housing to support top-mount explosion vents, heat sensors, fire suppression systems, alarm strobes, side-mount explosion vents and many more elements to provide better air purification.

Environment Friendliness
The three powerful components of PowerCore TF filter – TG filter packs with Ultra-Web media, Airflow Controller with VFD and Premium Efficiency Motor allow significant energy savings.

Ease of Maintenance
The PowerCore filter packs are easy to install and remove without the help of any tools. The Low-Inlet box has a dust drawer located at the bottom to collect the dust and it can be detached easily while cleaning.

A Few Last Words
The Torit PowerCore Dust Collector is an ideal filtration system for critical processes where harmful particulates need to be controlled. The heat sensors, fire suppression, inline spark cooler, reinforced housing construction and many more features of the system make it an efficient choice for different types of industrial facilities. If you wish more info on the dust collector, feel free to contact us for a no obligation free consultation.

Air Filter Installation

Increasing competitiveness and proliferation of numerous diseases necessitate facility managers to maintain optimum hygiene levels, with a major challenge being to stop airborne microorganisms. The majority of viruses and bacteria that infect patients exist in the form of air particulates, which often get ignored by patients, doctors as well as administrators. In this article, we discuss how HEPA air filter installation helps improve the hygiene levels in hospitals.

HEPA Air Filters: “The” Solution for Hospitals
HEPA purifiers are capable of extracting and cleaning approximately 99.97 percent of 0.3-micrometer dirt particles. Studies affirm that HEPA purifiers can easily remove up to 94 percent microorganisms, which makes them an ideal choice for healthcare facilities.

Why a Change Might be Imperative?
Against the strongest convictions of facility managers, most of the commonly used air purification solutions, such as ion purifiers, absorbents, and UV lights, fail to completely eliminate microorganisms. Therefore, none of these qualify for the much sensitive and vulnerable environment of healthcare facilities. Moreover, ionizing purifiers release ions that react with air, producing formaldehyde that may have an adverse impact on human health. Ultimately, it is quintessential for hospitals and other health service providers to install an HEPA filtration system, which is efficient to remove all the hazardous microbes and keep the complex cent percent hygiene.
In hospitals, it is quintessential that personnels work in the proper hygiene conditions. HEPA air filters installed have the capacity to effectively detect and track hazardous viruses and bacterium and provide protection to all the hospital staffs and patients as well. Normally, though with all the benefits of normal HEPA filters to detect and trap all the hazardous microbes from the atmosphere, it is important to install an efficient HEPA filter, which have the efficiency to remove individual and small viruses that range from 0.005 to 0.1 micron.

The Last Few Words
Without the installation of modified and an efficient HEPA filters the desired hygiene may be still a far-fetched objective. For the proper air filtration, it is quintessential to consult a reliable air-filtration and environmental specialists that hold an immense experience in providing a heuristic solution. In case, you need an information on our specially designed HEPA filtration system for hospitals, feel free to contact us.

When it comes to measures for fighting disease and infections in hospitals, specifically attaining maximum hygiene in Operating Rooms, it is essential to purify air from deadly microorganism particulates using HEPA Filters. For more information read here.

Black keyboard closeup with word FAQ

High-Efficiency Particulate Air or sometimes High-Efficiency Particulate Arrestance, (HEPA) is an issuing standard for air filters that are certified, manufactured, tested and labeled according to the filter standards by HEPA. There are several categories of HEPA classification and the minimum category requires filters to capture 99.97 percent of 0.3 microns present in the air. Being the gold standard of air filtration, it often raises some FAQs about the HEPA filtration, no matter whether you need AC filters in San Antonio or San Jose! Read on to get some of the essential information about HEPA filters.

1. What makes HEPA filters so highly efficient?

HEPA filters use super fine fiber that helps to capture even the tiniest of impurities that can pass through other filters. Originally designed in 1940s and used to prevent airborne radioactive contaminants from spreading during the Manhattan Project. HEPA filters need to be tested and certified to meet the requirements of an HEPA filter and prove that it is efficient to remove 99.97 percent of particles of 0.3-micron diameter that pass through the filter.

2. Are HEPA Media Filters and HEPA filters the same?

No. A filter manufactured with HEPA filter media doesn’t imply that it meets HEPA efficiency requirements. A tiny leak in the media may compromise the efficiency of the filter and it may fall below HEPA standards. A filter meets HEPA filters only after it has been thoroughly tested following the industry standards to ensure the performance and efficiency of the filter.

3. Are HEPA filters apt for isolated wards in hospitals?

The highly infectious wards in hospitals demand better air purification controls and as per the current Center for Disease Control and Prevention (CDC) guidelines, HEPA filters make the cut. HEPA filters capture contaminants that are present in isolation rooms including pathogens and microbial spores.

4. Does the performance of HEPA filter lower with time?

No. Unlike the electrostatically charged air filters, the efficiency of HEPA filters is not affected as they become dirty. The efficiency of HEPA filters increases as they get dirty. While that surprises most people, it is true.

5. How often should HEPA filters be replaced?

The frequency of replacing air filters depends on factors such as the size of airborne condiments, the concentration level of airborne contaminants, the level of humidity in the area. No matter whether you are looking for commercial AC filters in San Antonio or for that matter in any part of the US, HEPA filters may or may not come with an indication system that notifies users when it’s time to replace the filter, depending on the model you buy.

So, those were some of the common questions that people have about HEPA filters. We hope we were able to put an end to at least a few of your queries about HEPA filters. If you wish to learn more or need professional consultation on HEPA filters, our experts will be happy to help.

NAFA Summer 2015

NAFA Summer 2015

Get all the insights regarding their activities of NAFA (National Air Filtration Association), including a round-up of the TECH 2015 event and the new management firm running things at NAFA.

Catch all the latest technology in air filtration, quality brands, as well as all the buzz and updates. PDF also contains a note from the Executive Director of NAFA, Al Veeck.

Choosing the right HVAC filterChoosing the right HVAC Filters for your facility doesn’t have to be complicated, but it does require attention to details including submicron particle capture efficiency, energy consumption implications and more. If you don’t focus on the right performance factors, you may end up with an air filter system that’s just wrong.

The safest route is to let a specialist consult you, but here are some helpful tips to ensure you are making the right decision.

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