Skip to Primary Navigation Skip to Site Navigation Skip to Main Content All Site Map

3M Purification Inc.

Featured Products
Our Brands
3M™ Commercial Air Filtration FAQs


Why is Indoor Air Quality important?

According to the EPA, "Indoor air quality is a major concern to businesses, building managers, tenants, and employees because it can impact the health, comfort, well being, and productivity of building occupants.

Most Americans spend up to 90% of their time indoors and many spend most of their working hours in an office environment. Studies conducted by the U.S. Environmental Protection Agency (EPA) and others show that indoor environments sometimes can have levels of pollutants that are actually higher than levels found outside.

Pollutants in our indoor environment can increase the risk of illness. Several studies by EPA, states, and independent scientific panels have consistently ranked indoor air pollution as an important environmental health problem. While most buildings do not have severe indoor air quality problems, even well-run buildings can sometimes experience episodes of poor indoor air quality.

A 1989 EPA Report to Congress concluded that improved indoor air quality can result in higher productivity and fewer lost work days. EPA estimates that poor indoor air may cost the nation tens of billions of dollars each year in lost productivity and medical care."

More information from the EPA on why indoor air quality is important

Why is filtration important?

Air filtration is important as it may help to protect equipment and minimize coil fouling. Filtration is also important as it may help to reduce the amount of airborne particulates entering the building (e.g., dust, pollen, spores).

What is MERV?

Minimum Efficiency Reporting Value (MERV): A particle capture efficiency measure for air cleaning devices (e.g., air filters) defined by ASHRAE Standard 52.2. MERV ratings range from 1 to 20 and are determined by testing the device's efficiency at removing salt (potassium chloride) particles as a function of particle size over the size range from 0.3 to 10 µm. This data is then used to assign a MERV rating from 1 (lowest efficiency) to 16 (highest efficiency) using the criteria included in the standard. MERV ratings 17 through 20 are assigned based on testing by a separate method that is referenced in the standard.

More Information on ASHRAE…

What is MERV A?

ASHRAE has developed a separate test that includes a filter conditioning procedure to determine the magnitude of the efficiency loss that an electret based filter may realize in use. The conditioning step is representative of the best available knowledge to simulate in a controlled laboratory setting the minimum expected in actual use.

The method of conditioning is included in the ASHRAE standard 52.2. – 2007 as Appendix J. When the test in Appendix J is used, the data output obtained from the efficiency test procedure (KCl conditioning step) is referred to as MERV A. The data output value is thus differentiated from the MERV value (which is the data output of the test without the KCl conditioning).

Why is 3M using MERV A ratings for its Commercial HVAC filters?

Filter performance may be impacted in actual use so it is only logical to use a measure that would reflect the efficiency loss a filter may realize. 3M feels that this is a more accurate representation of the filter performance over its life cycle and would help customers in their decision-making process.

What is air bypass?

Air will tend to find the path of least resistance. This "bypass" often occurs when air passes between the filter frame and the filter rack.

What is "face loading" and "depth loading" and why does it matter?

Face loading
Particles are captured on the surface of the filter, but not throughout the entire depth of the filter. Face loading typically results in filters with considerably shorter filter life, when compared to depth loading filters.

Depth loading
Particles are captured throughout the entire depth of the filter, not just the surface.

Why it matters
Filters with depth loading characteristics have generally a longer filter life, compared to filters that have face loading characteristics. 3M™ Commercial HVAC Filters use an innovative, open filtration media structure that allows particles to be captured throughout the depth of the filter (=depth loading) and therefore have a longer filter life when compared to many products that display face loading characteristics. And a longer filter life means less change-outs therefore less labor.

Filter loading characteristics — Face loading vs. Depth loading

What is 'face loading' and 'depth loading' and why does it matter?

What is pressure drop?

Pressure drop (dP or ΔP): The air static pressure differential between the upstream and downstream side of a mechanical HVAC component such as the cooling coil or air filter rack. Typically measured in units of inches of water. Measurement must be accompanied by air velocity to be of use (e.g., 0.37 inches of water at 500 feet per minute). Same as airflow resistance.

What are some of the key factors to consider when choosing a new air filter system?

  • Low pressure drop
  • High particle capture efficiency
  • Robust design with synthetic media and frame
  • UL 900 Class 1 flammability classification

What does "UL 900" mean?

The UL 900 Standard establishes the flammability requirements for HVAC filters. Originally, the filters were classified in "Class 1" and "Class 2", when they are new (=clean). However, it has been reasoned by UL, and other parties in the HVAC Filter industry that in actual applications used "Class 1" filters may perform no differently than a "Class 2" filter. Effective May 31, 2012, HVAC filters performing to at least a "Class 2" will then have the "UL 900" rating, the same rating as an HVAC filter of "Class 1" would have.

This is the scope of the UL Standard as listed on the UL-Standard web site:
1These requirements cover tests to determine the amount of smoke generated and the combustibility of air filter units of both washable and throwaway types used for removal of dust and other airborne particles from air circulated mechanically in equipment and systems installed in accordance with the Standards for Installation of Air Conditioning and Ventilating Systems, NFPA 90A (Other Than Residence Type), Installation of Warm Air Heating and Air Conditioning Systems, NFPA 90B (Residence Type), the International Mechanical Code, the International Fire Code, and the Uniform Mechanical Code.

Since the smoke generation of an air filter unit, as well as its combustibility, depends upon the nature and quantity of the material collected by the filter, the test requirements of this standard, for classification purposes, apply only to air filter units in a clean condition. Consequently, when filters are susceptible to the accumulation of combustible deposits, it is intended that maintenance and inspection practices should be followed as proposed in Appendix B of NFPA 90A.
Revised: Effective May 31, 2012


How is "UL 900" different from "Class 1" and "Class 2" ratings?

Traditionally there have been two class ratings: "Class 1" and "Class 2". The "Class 1" requirement is more stringent than the "Class 2" requirement. This classification rating will be changed to "UL 900", effective May 31, 2012.

What does this change mean for 3M™ Commercial HVAC Filter Products?

The construction of our 3M™ Commercial HVAC Filter Products remains the same. Previously carrying the "Class 1" rating, they will now carry the "UL900" rating to reflect the new standard, effective May 31, 2012, but the HVAC Filters themselves will not change.

What is the USGBC?

The U.S. Green Building Council (USGBC) is a non-profit organization committed to expanding sustainable building practices. USGBC is composed of more than 12,000 organizations from across the building industry that are working to advance structures that are environmentally responsible, profitable, and healthy places to live and work. Members includes building owners and end-users, real estate developers, facility managers, architects, designers, engineers, general contractors, subcontractors, product and building system manufacturers, government agencies, and nonprofits.

More information on USGBC…

What is LEED Certification?

The Leadership in Energy and Environmental Design (LEED) Green Building Rating System™ is the nationally accepted benchmark for the design, construction and operation of high performance green buildings. LEED provides building owners and operators with the tools they need to have an immediate and measurable impact on their buildings performance.

More information on LEED…

What is PM2.5

"Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

The EPA groups particle pollution into two categories:
"Inhalable coarse particles," such as those found near roadways and dusty industries; they are larger than 2.5 micrometers and smaller than 10 micrometers in diameter

"Fine particles," such as those found in smoke and haze; they are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.

More information about Fine Particle (PM2.5) Designations

Why does EPA issue AQI forecasts only for ozone and particle pollution?

AQI reporting is required for all criteria pollutants when they have an index value of 50 or above. Most cities forecast for ozone and particle pollution as these pollutants are the major sources of unhealthy air quality around 99% of the time. However, several cities forecast for all five pollutants — ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide, and nitrogen dioxide.

More information on AQI forecasts... (PDF, 904 Kb)

How do electrical energy use reductions translate into reductions in greenhouse gas emissions?

Reducing the electrical energy used in a facility not only saves you money on your utility bill, it also contributes to a reduction in greenhouse gas emissions to our environment for those customers whose utility requirements are met by fossil fuel energy generation.

Take a look at this table to find out what savings in electrical energy use translate to in every day terms.

Greenhouse Gas Equivalencies (PDF, 61 Kb)

For additional examples for Greenhouse Gas Equivalencies visit:

How can I save energy with 3M™ Commercial HVAC Filters?

Use of 3M™ Commercial HVAC Filters may help reduce electrical energy consumption due to their low airflow resistance when compared with filters at comparable efficiency ratings and construction. Savings may be even greater and may help increase your return on initial investment, when air handling units are cleaned.

Why should I buy 3M™ Commercial HVAC Filters?

  • Potential reduction in electrical energy consumption, due to low pressure drop
  • Longer filter life than many comparable products, due to unique combination of depth loading filtration media, precision pleat structure, and high filter media area
  • Reduced labor hours and maintenance, due to hassle-free installation and excellent filter life
  • Low chance of filter damage during handling and installation, due to tough filter construction

Other 3M Filtration Products

Filtrete™ Home Filtration Products
For over 15 years, 3M has developed innovative filtration solutions for a cleaner, better indoor home environment - making Filtrete the leading brand* in 1" residential air filters.

For more information, please visit us at

Filtrete™ Automotive Cabin Air Filtration Products
3M now offers Filtrete™ Filters for your car. Our filters are currently available for certain models of Toyota® and Honda® vehicles. Filtrete™ Automotive Cabin Air Filters can help clean the air in your car by capturing airborne particles and pollen.

For more information, please visit us at

Specialty Filtration Products
3M uses air filter media for custom filtration applications to meet our customer’s unique needs. It is ideal for applications where high efficiency, low pressure drop and high loading are critical and space is at a premium. This media contains electrostatically charged fibers that work like magnets to attract and capture particles.

For more information please call 1-800-648-3550

Vacuum Cleaner Bags and Filters
Custom designed to manufacturer specifications, 3M supplies filters and bags to various customers throughout the floor care industry.

For more information please call 1-800-648-3550.

*Based on 2005 AC Nielsen panel data

HVAC Industry Links

Green Building Council Member
National Air Filtration Association
Energy Star Partner