Part 2 of our series, “Answers to frequently asked questions about air filtration,” covers topics such as energy and cost savings, air filters for pharmaceutical applications, MERV ratings, the lifespan of air filters, and how to tell if your air filter is clogged. In addition to these topics, we also address the importance of regular maintenance and replacement of air filters for optimal performance. We provide tips on when and how often you should change your air filters to ensure a clean and healthy indoor environment. Furthermore, our experts discuss the signs that indicate a clogged air filter, such as decreased airflow, increased energy consumption, pressure drop, and poor air quality. By understanding these aspects, you can effectively maintain your air filtration system and enjoy its benefits in the long run. Read Part 1

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How can you reduce the total cost of ownership (TCO) of an air filtration system?

Many look at the initial cost of a filter and don’t take into consideration the extra labour cost involved in filters that require more maintenance, and require more transportation for delivery and disposal, as well as not looking at costs associated with more energy consumption for higher average pressure drop filters. It is important to factor in all those costs for a longer period, and from there estimate how many times a filter will need to be changed-out and then multiply the cost. The total cost of ownership is always calculated within a longer time frame instead of just initial purchase costs. See Camfil’s cost-saving calculator.

Using a high-quality air filter designed to work with a variable frequency drive (VFD)-controlled fan can save you a considerable amount of energy while maintaining good indoor air quality. A reduction in fan speed can reduce that fan’s use of electricity by up to 70%.

In terms of material costs, changing-out a filter every three months at $5 per filter will cost $20 per year. Changing-out that filter twice a year at $8 per filter only costs $16 per year.

What is a MERV rating in air filters?

The rating system known as MERV, which stands for “Minimum Efficiency Reporting Value,” is used to show how effectively air filters capture particles of different sizes. MERV ratings range from 1 to 16, with MERV-16 offering the greatest level of particle capture and MERV-1 offering the least. The MERV rating system was established by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 

ASHRAE 52.2 Appendix J was developed to test air filter efficiency throughout the life of the filter, even after the electrostatic charge dissipates. Camfil recommends that all filter users request this optional testing step to ensure that they are truly receiving the particle removal efficiency they are expecting. Filters tested with this optional step are designated “MERV-A,” for example, MERV-13-A.

How do mechanical air filters work?

One way air filters work is by keeping particles from going through air filter media by forcing air through a fine mesh that traps harmful particles. Mechanical air filters attract particles to the fibres until the fibres are coated, whereas with air filters that have an electrostatic charge, the charge will soon start dissipating, and fewer and fewer particles will be drawn to the media over time.

How do you dispose of air filters?

In most cases, if it’s just a general application, air filters are thrown out in dumpsters and end up in landfill sites. It is important to reduce the amount of filters used by purchasing filters with a focus on efficiency and longevity. Some companies are now starting to recycle as much as they can, so they may tear apart the filters. It is labour-intensive, but it can be done, and certain components can be recycled while others are disposed of in bins.

There are different protocols when collecting medical waste, nuclear by-products, or other hazardous waste. In such instances, the waste must be disposed of following government or industry safety standards.

Nuclear waste is another story altogether. Most of the air filters in nuclear plants don’t come into contact with radioactive particles, and those filters can simply be disposed of in a landfill because there is no danger involved. Most importantly, it’s important to consider where the air is coming from. As long as it’s not being drawn from a volatile zone where radioactive particles are produced or processed, air filtration best practices are the same as any office or public building. There are stringent regulations in place for dealing with air filter waste that comes in contact with nuclear waste or by-products.

How long do air filters last?

Air filter life depends on how well they are designed. The quality of the materials used, such as the media, is essential in determining longevity. High-quality air filters can last over two years, but longevity can vary from heavy-duty to light-duty applications. Portable air purifier units can last from five to ten years, based on manufacturer specifications.

How do you save energy with air filters?

The most important consideration is to make sure you have VFD control systems for your fans. Once you have a VFD-controlled fan in place in the air filtration system, use an air filter tested to have the lowest average pressure drop. In order to decide the optimal pressure drop to ensure the highest energy savings, the filter should be changed-out at approximately twice the initial pressure drop and based upon similar air velocity as a baseline.

It is also important to use a timer for VFDs. Fans should be timed to run at lower speeds when maximum air circulation and filtration are not required—for example, in an office building from 10 pm to 6 am. Never never lock VFDs in at 100% power. Some people do this to reach maximum airflow, but when fans run at 100% speed, energy cannot be saved because more energy is required.

Can you wash air filters?

Yes, there are a few air filters that are made of washable metal or hogs’ hair, but their MERV efficiency is too low. Synthetic, high-loft fibreglass and wet-laid glass are not washable, and neither are HEPA filters. The only other air filters that can be washed or cleaned are some synthetic dust collector cartridges.

Why are my air filters getting dirty so fast?

When people ask this question, it is usually because the air filter looks ‘dirty.’ But even filters that look dirty could still be functioning at or near peak efficiency. Lint from furniture and dirt from carpets can contribute to this. Also, construction debris and dust from dirt roads get drawn into the homes, offices, or schools and then get into air filtration systems, but keep in mind when people worry that their filters are dirty, that’s what they’re for. Air filters collect contaminants and get dirty, but the most important question is, is it clogged up?

How do I know if my air filter is clogged?

The only proper way to know if a filter is clogged is by using a Magnehelic gauge. Measuring airflow to see if it is decreasing is another way to tell if your air filter is clogged. Also, look for any bowing of the filter, as it is a sign that the filter may be reaching the end of its life.

What do activated-carbon air filters remove from the air? Do carbon air filters remove volatile organic compounds (VOCs)?

Molecular air filters and molecular air cleaners remove odours and do a great job of removing VOCs as well. These units can deal with many issues, including formaldehyde, off-gassing and general odours. All Camfil molecular filters utilize a technique known as adsorption. In simple terms, this means sticking the molecules onto materials with extremely high surface areas, with activated carbon or activated alumina as the active ingredient. Molecular air filters contain a range of adsorbents, including activated carbon, carbon impregnated with a wide range of chemicals for enhanced performance, activated alumina with permanganate impregnation, as well as blends and hybrid media. Read more about molecular filters.

What is better, a HEPA or an ULPA filter?

ULPA filters have a particle capture efficiency of 99.999% at 0.12 microns (µm), and HEPA filters at 99.97% at 0.3 microns (µm). ULPA filters are used when the absolute most efficient air filtration process is required. Usually, it’s the end-user or an engineer who decides whether they need such efficiency or not.

When should portable air cleaners or air purifiers be used?

According to the National Institute of Environmental Health Sciences, “Portable air cleaners may be beneficial when additional ventilation with outdoor air is not possible, or when it compromises indoor temperature or humidity, or when outdoor air pollution is high.” Also, portable air cleaners can be used when commercial or residential buildings have problem areas that don’t benefit from good air circulation or proper air filtration because of the density of furniture or equipment or architectural constraints. 

What air filter should you use in an aseptic area or a clean room?

Depending on how crucial it is to keep contaminants out of a particular area, the type of air filter used in an aseptic area or cleanroom—also known as a sterile environment—varies. A pharmaceutical research or production facility may need to operate with higher efficiency standards in some areas but not others. For instance, higher-efficiency air filters are necessary in packaging areas. For cleanrooms, an ULPA filter or HEPA filter must remove the air’s most harmful particles and stop them from settling on surfaces. The expected life of the filter should be a strict criterion because downtime in these applications can be costly. Standards are set by the Institute of Environmental Sciences and Technology (IEST).

Which air filters are used in the Pharmaceutical industry?

A wide variety of air filters are used in thepharmaceutical industry, from pleated or pad filters to HEPA filters or dust collection filters. Because downtime at a pharmaceutical company is very costly, air filtration systems for the pharmaceutical industry must be carefully considered.

For example, if a company makes millions of dollars worth of product every hour and its air handling equipment goes down for even one hour, it can be quite costly. Pharmaceutical companies should be using premium products that last the longest and are engineered to be the most durable, so there’s less concern for downtime as well as fewer issues of liability in manufacturing.

Why do pharmaceutical applications require the best HEPA filters?

In any of the processing areas, cleanrooms, places where vials are being filled, or tablets are being processed, as well as in mixing areas, HEPA filters are necessary. Anywhere the product is in the air or available to the airstream, the highest-efficiency filters must be used to maintain purity and efficacy.

When are bag-in-bag-out (BIBO) filters used in pharmaceutical settings?

Only in critical applications where the contaminated equipment or waste can be harmful.

BIBO units are only used where there’s a serious concern for human health, as contaminants are hazardous. Camfil produces bag-in-bag-out containment housings designed for side-loading for critical applications in industries and research facilities handling dangerous, toxic, biological, radiological, or carcinogenic materials.

In pharmaceutical settings, are there different types of HEPA filters?

HEPA filters have a minimum particle capture rate of 99.97% with a size of 0.3 microns (µm). There are mainly two types of filters: a box-style filter and a ceiling module. A box-style filter is usually 12 inches deep and fits into a frame that can be placed anywhere within a duct or air handling unit. Ceiling panels are actually placed in ceilings as the last entry point for air coming into a room to keep any particles from coming into the area.

To consult with an air filtration expert on the topics covered in this post or for further information, please use this contact form, and an air filtration expert from Camfil Canada will answer any questions you may have.

About Camfil Canada Clean Air Solutions

For 60 years, Camfil has been helping people breathe cleaner air. As a leading manufacturer of premium clean air solutions, we provide commercial and industrial systems for air filtration and air pollution control that improve worker and equipment productivity, minimize energy use, and benefit human health and the environment. Read more about Camfil Canada



Camfil Canada Air filter expert Berni Baier

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Camfil Canada Inc.

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