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Double IAQ Advantage: Better Filtration and Reduced Total Cost

A major healthcare facility jumps at the chance to improve air quality and reduce costs.

Like many other health care providers, Atlanta-based Emory Healthcare keenly is aware of issues that affect the cleanliness of the indoor environment, particularly air quality. They have a commitment to maintaining high air quality standards in all of their facilities. Recently, the facility had the rare opportunity both to upgrade its indoor air quality, and to substantially reduce air filtration costs as well.

A recent evaluation by mechanical contractors Batchelor & Kimball of energy wheels and related components at Emory University Hospital Midtown showed that air filtration significantly could be enhanced by replacing the facility's four-stage air filter configuration. This 90,000 cfm penthouse system — the largest of many air-handling units at the facility — uses 56 each of three types of filters. A synthetic bag filter was used for exhaust air, four-ply ring panels and a synthetic bag filter were the prefilters and 2V “graduated-density” air filters were used as final filters.

Following a review of product test and performance documentation, along with detailed projections that were specific to the Emory University Hospital Midtown system, Batchelor & Kimball, which works with Thermal Recovery Systems (TRS) and Air Filter Sales & Service (AFS) of Atlanta, selected Camfil Farr filter technology for all three requirements, including 30/30 pleated, 2-inch filters that replaced the synthetic bags on the return air banks; Hi-Flo pre-filters; and Durafil final filters.

The material found in the 30/30s is a blend of natural and synthetic fibers that maintain consistent, high removal efficiency throughout the filter's life. These filters specifically were engineered for health care, cleanroom and similar environments, where low initial resistance and low maintained resistance to airflow are required.

Hi-Flo bag prefilters, which use high lofted air laid microfiber media, were specified to remove fumes, bacteria, fungi and virus-bearing droplet nuclei, as well as nuisance contaminants, including pollens, which are plentiful in this area of Georgia. The initial installation of these prefilters has been in service 19 months without reaching the initial resistance of the former filters used in this application.

The engineering behind Durafil final filters produces system energy savings of 20 percent to 35 percent compared to standard “V-shaped” filters, and 25 percent to 50 percent versus other final filter product designs, while providing MERV 14 performance for the entire life of the filter. MERV (minimum efficiency reporting value) 14 is an efficiency rating applicable to all patient care environments.

The issue of pressure drop is central to decisions about filtration because of its correlation with both filter performance and the energy required by the air handling system. Eleven months after the upgrade at Emory University Midtown, the filter configuration produced less than one-third of the previous level of filter drop. This is notable because pressure drop directly impacts system horsepower requirements.


If equipment service life is important, filter life is as well, and in a more immediate sense. The labor cost to change 224 filters, not to mention the cost of the filters themselves, is substantial for any large facility. The standard procedure at Emory Healthcare, as with most facilities, had been filter change-out based on a calendar-driven preventive maintenance (PM) schedule. The PM schedule does not address filter pressure loss, which varies directly with filter loading. Outside air pre-filters were changed on a regular interval with no basis related to filter performance or system effect.

By using Dwyer Magnehelic gauges to measure pressure loss rather than fixed calendar change-outs, Hi-Flo outside air filters (without pre-filter protection) consistently provided a fully productive service life of 18 months or more, thus reducing filter, labor and administrative costs significantly. By using the same pressure loss standards, final filter service life was extended to 24 months, rather than the 12-month scheduled life, also a significant savings.

Emory University Midtown's successful test has led to other opportunities within the Emory Healthcare system. Emory recently opened Emory Orthopaedics & Spine Hospital, and Batchelor & Kimball again selected TRS and AFS to upgrade surgery suites with ceiling module HEPA filters, and 30/30 and Durafil filters were installed throughout the remainder of the facility.

Another Emory facility, Emory University Hospital, has installed 30/30s as pre-filters and the new-generation ES Durafil for final filtration on more than 1.3 million cfm of filtered air. Jerry Lewis, director of facilities of Emory University Hospital, reports that all surgery suites are being retrofitted with high-capacity ceiling module HEPA filters.

Nearby, Emory Healthcare's Wesley Woods geriatric care facility has joined the program to retrofit with 30/30 pre-filters and the Durafil ES final filter.

In addition to reduced operating costs, there are other benefits to the new air filtration systems. Explains Robyn Napier, AFS sales technician, “Night shift maintenance workers at Emory University Midtown [previously] told us that they were ‘too hot’ and ‘too cold.’ Complaint calls are far fewer now because of the lower system resistance and more uniform air handling performance.”

“Performance documentation and cost reductions for all these facilities have been well documented,” adds TRS' Phil Chapman. “Also, we have generated for each facility a notebook, which we maintain, that contains detailed spread sheets for each individual air handling unit. So, when the Joint Commission wants to check the systems, they can see the facility meets or exceeds current accepted good practice. Data from the American Society of Heating, Refrigeration and Air Conditioning Engineers and other documentation are included. All facilities are using 5 Star Energy Efficient GREEN Filters and reaping the benefits of better patient care and less energy usage.”

The obstacle in many hospital groups, Chapman adds, is pressure to use what the buying groups want. These groups sell pre-selected products based primarily on purchase price, rather than true life cycle costs, which include energy, materials and labor.

“This is unfortunate,” he says, “because considering only the cost of energy to operate the air handling system, the return on investment for the 5 Star Energy Efficient filters is less than 1 year. After that, savings are substantial — and recurring.”

Kevin Wood is vice president of sales and marketing for Camfil Farr.

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