Proper Filtration Key To Protecting IAQ

Pollen, dust and other particulates invisible to the naked eye may trigger allergy and asthma symptoms in building occupants, requiring building service contractors to train a watchful eye on maintaining indoor air quality (IAQ). An adequate vacuum filtration system that both picks up and captures debris helps create better IAQ for building occupants.

Many filter types exist to help prevent poor IAQ, among them: HEPA (high-efficiency particulate air) filters, ULPA (ultra-low-penetration air) filters and microfiber high-efficiency filters. HEPA filters offer a minimum particle collection efficiency of 99.97 percent at 0.3 microns, ULPA filters collect particles at an efficiency of 99.99 percent at 0.1 to 0.2 microns, while high-efficiency filters capture particles down to 1 micron.

“The better job we do of vacuuming, the less dust will be in the facility overall, which directly contributes to indoor air quality,” says Paul Greenland, president of Aetna Building Maintenance, Columbus, Ohio.

Making sense of the array of filter choices can be confusing. How much filtration is adequate for BSCs, and is there such a thing as too much filtration?

“A lot of people really do not understand filtration,” says Paul Condie, director of operations at KBM Building Services of San Diego, Calif. He points out companies often specify HEPA or ULPA filters without a clear idea as to why.

Filtration

For routine carpet care in commercial facilities, high-efficiency filters should be sufficient. These filters generally remove hair, dust mites, pollen and pet dander — particles found in typical office environments. Even though HEPA is a current buzzword for facility managers, these filters are not always necessary.

“Do HEPA filters work? Absolutely,” says Allen Rathey, president, InstructionLink/JanTrain Inc., Boise, Idaho. “But everyone thinks they have to have them to clean well, and that’s just not so. A lot of vacuums that are not HEPA filtered are very efficient and clean and retain dust just as well.”

If BSCs are offering cleaning for health services, then they may want to consider stronger filters. HEPA filters will also capture bacteria, yeast and mold, while ULPA filtration captures viruses and tobacco smoke as well.

Most often, HEPA or ULPA filters are required in cleanroom environments, such as those found in hospitals, says Condie.

In order to achieve proper filtration, it’s important to consider how many filters a vacuum has. Machines with multi-stage filtration pick up the largest particles in the first filtration stage then move to progressively finer filters as dust travels through the unit. Rathey recommends vacuums with at least two levels of filtration: a primary filter that captures large particles and a secondary filter to collect fine dust.

“The primary filter is necessary so that the secondary filter doesn’t load up in five minutes,” says Rathey.

Choosing the proper filter is just step one. Improving IAQ also depends on vacuum selection and adequate maintenance.

The right vacuum

When selecting a vacuum it’s critical that BSCs verify the machine’s features. Just because a vendor claims to have a HEPA vacuum does not mean the unit doesn’t blow contaminants into the air.

“All vacuums are not created equal,” says Rathey. Only when companies offer definitive data, from third-party sources, showing their vacuums work as specified, should BSCs trust these claims.

One organization that certifies green vacuums is the Carpet and Rug Institute (CRI) in Dalton, Ga. Its Seal of Approval certification (and former Green Label program) tests for the amount of soil removed from the floor, the vacuum’s effect on the carpet pile, and how well the machine contains dust and prevents it from blowing back into the air, says Werner Braun, CRI president.

The Seal of Approval certification is broken into three ratings: Gold, Silver and Bronze. Vacuums achieving a Gold rating cannot release more 35 micrograms per cubic meter of air emissions, and remove the most soil from carpets.

It may surprise some contractors, but many Gold-rated vacuums do not have HEPA or ULPA filters.

“Whether it is HEPA or non-HEPA in some ways is irrelevant,” says Rathey. “What is relevant is what’s coming off that vacuum from its orifices, which is exactly what CRI measures.”

In addition to a third-party certification, other features are important when selecting a vacuum. First, the vacuum should be a sealed unit that keeps air inside to push particulates through its filters. Without a sealed design, the machine releases dust through its gaps.

“That’s invisible dust,” says Rathey. “Anything smaller than 10 microns adds to the environment and affects air quality but you cannot see it.”

BSCs should also examine the machine’s airflow and lift. Vacuums require sufficient airflow to lift particles from the carpet, as its force is what picks up debris and moves it into the machine. Without adequate airflow and lift, vacuums simply blow dust around. Airflow is measured in cubic feet per minute (CFM) while lift is calculated in inches.

“The higher those two numbers, the better the vacuum’s performance,” Rathey says.

The size and width of vacuum attachments and heads also matter. Tools with a narrow opening will have greater suction ability, says Rathey.

Top working order

The best vacuum design in the world, equipped with the highest level of filtration, may quickly be rendered useless without sufficient maintenance. Airflow and lift plummet as filters load. A vacuum with an overloaded filter redistributes dust back into the air where it ultimately settles on every surface in the room. Pushing harmful contaminants back into the breathing zone also presents risk to vulnerable populations, such as children or those with asthma or allergies.

“If you’re not aware of the state your filter is in, you’re not vacuuming properly,” says Rathey.

KBM maintains a policy to clean for health, not appearance. Vacuum maintenance plays a tremendous role in KBM’s strategy. On the last day of every workweek, KBM custodians replace every unit’s micro-filters then wash the remaining three filters and hang them to dry. Custodians reassemble the units on Monday for the week ahead. During the week, workers empty micro-filters every two hours into small plastic liners. Supervisors inspect these liners, expecting about 3 ounces of dust.

“If there’s a problem before the end of the week, we don’t wait until then to change the filter,” Condie says. “There are people I know who never replace vacuum filters because they think filters last the life of the vacuum. That simply isn’t so.”

Once on the job, KBM utilizes a team cleaning approach where light duty specialists remove large debris before vacuum specialists perform their duties. This ensures vacuums do not pick up debris that might damage them or tear their filters.

Vacuum filters help keep harmful contaminants out of the air, but without a quality vacuum, adequate maintenance, and solid training and policies, those tiny dust catchers can do more harm than good.

Ronnie Garrett is a freelance writer based in Milwaukee.