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Dealing With Schools’ Ventilation Problems

June 30, 2011

Officials at Keefe Technical School upgraded filter efficiency and found out the improvement keeps the ductwork clean while operating the heating and cooling coils at peak energy efficiency.

Statistics from the National Center for Education Statistics are a bit unnerving: 53 million school children and 6 million teachers, administrators, and others walk into 120,000 school buildings every day — and at least 50 percent of these schools have been diagnosed with indoor air quality (IAQ) problems.

According to a report from the National Air Filtration Association (NAFA), the United States is placing too many kids in jeopardy by exposing them to buildings that are less than conducive to a positive, healthy learning environment.

The Department of Energy (DOE) echoed that thought in the following statement: “Our nation’s K-12 schools are challenged to serve a growing student population and rising community expectations with aging buildings, constrained operating budgets, and ever-increasing energy bills.” It added, “When taken collectively, schools are a major consumer of energy — some 425 trillion Btu per year — 7 percent of all energy used by commercial buildings.”

Each year, taxpayers spend $6 billion on energy for these schools, about 25 percent more than necessary, according to the Energy Efficiency and Renewable Energy, DOE. Turning that number around, it said that $1.5 billion could be redirected to hire 30,000 new teachers or purchase 40 million new textbooks annually.

Add to this another alarming statistic: The American Lung Association estimates that 6.3 million school-aged kids miss some 10 million school days with various types of asthmas. In fact, it said asthma is the leading cause of school absenteeism due to chronic illness. The Centers for Disease Control and Prevention estimates approximately 14 million school days per year are lost because of asthma exacerbated by poor IAQ in schools.

The American Public Health Association states, “… every child and school employee should have the right to an environmentally safe and healthy school that is clean and in good repair.” While many school IAQ problems can be solved with good engineering practice and proper maintenance or repair, NAFA said cleaner air provided by increased levels of air filtration provides the solution upon which many of the IAQ problems develop.


Because schools represent a much denser population percentage than a typical commercial office building, the bioburden becomes even greater. Viable and nonviable particulates can be brought in on people’s clothing and through open doors and windows. Furthermore, the activity level of most young people, which increases the shedding of skin cells and other particulates, makes school air some of the dirtiest air in any environment, according to NAFA.

The association said many schools use low-efficiency (MERV 1-4) filters that remove minimal levels of all particulate matter.

In a report, “Air Filtration for Schools,” NAFA wrote: “For any parent who has taken their child to school first thing in the morning and picked them up in the afternoon, the difference in the smell of the school at the end of the day is astonishing. For those in the school, they have become accustomed to the odor and do not realize their air is full of particulates and odors.”

H.E. “Barney” Burroughs, a consultant with Building Wellness Consultancy, noted, “When the building’s air filters do not remove the particles from the air, the occupants’ lungs become the filter.”

NAFA said it is trying to counter this problem at schools with its Certified Air Filter Specialists (CAFS). Here are just two examples.


Norspec Filtration Ltd., located in Sarnia, Ontario, worked with the Thames Valley District school board beginning in 2000. Officials at Thames Valley realized that their low-bid contract for air filters was not working when parents, teachers, and custodial staff began complaining. They revised their air filter requirements with the note that they were looking for solutions to their air quality problems.

Norspec made a presentation to the school board outlining an air filter management program that included replacement of all low-numbered MERV filters with MERV 8 pleated filters along with MERV 8 synthetic ring and link panels. Next, Norspec assisted with development of a changeout schedule that involved a three-month survey of all 195 school locations to verify size, quantity, and existing status of the air-handling system.

They also worked with the school district to assemble a “filter committee” with representatives from Norspec, along with school officials and personnel from purchasing, maintenance, and health and safety that met on a quarterly basis to assess proposed solutions along with addressing any filter issues brought to the committee.

Each school had its own filter change schedule and filter order sheet with specific times and dates for ordering and changing. The filter committee monitored the program. This monitoring revealed that the individuals involved in changing air filters knew little about air filtration. With more than 400 people involved, Norspec held five training sessions, one in each region of the district. Over the intervening years, this training has become a yearly event to accommodate new personnel and reacquaint existing employees with filtration concepts.

According to Norspec Filter president Bob Jackson, CAFS, the filter committee continues to meet regularly to discuss issues, troubleshoot problems, and look for better ways to improve overall air quality. As a result of this partnership between the school district and Norspec, the school has realized cost savings from reduced changeouts in many schools, along with reduction of storage and damage.

According to NAFA, with the increase in air quality at the schools, the board has reported significant cost savings in other areas such as housekeeping and equipment maintenance. In 2004, Norspec Filter nominated Thames Valley District Schools for the NAFA Clean Air Award, which it subsequently received.

“This case study shows the value that NAFA-member companies can bring to facilities with knowledge and training along with higher-efficiency filters to help provide clean air in the schools,” said Alan Veeck, executive director of NAFA.


The Keefe Technical School, located in Framingham, Mass., is a 30-year-old facility with approximately 300,000 square feet of space. It provides classes and training for 13 different vocational/technical careers. It recently went through a filter upgrade, which improved the school’s IAQ.

Keefe Technical School, Framingham, Mass., is a 30-year-old facility with approximately 300,000 square feet of space. It provides classes and training for 13 vocational/technical careers including automotive, woodworking, plumbing, electrical, and various other grades. The school also has a gymnasium, swimming pool, and offers several cooking classes.

After having the school’s ductwork cleaned, it went looking for ways to keep its HVAC system components hygienically clean to improve and maintain acceptable IAQ for the students, faculty, and staff.

Plant engineer Ken Whidden arranged for instruction, training, and testing for custodial and maintenance staff, including HVAC supervisor Tim Rivers, with the latest technology required to maintain the school’s HVAC air filtration systems. The training programs included the U.S. Environmental Protection Agency’s “Tools for Schools” program. The staff also participated in and successfully completed training and testing of NAFA’s National Certified Technician (NCT) program. Helping along the way was Air Industries of North Andover, Mass.

According to Stephen Nicholas of Air Industries, the original filters were a 20-25 percent, MERV 6, cartridge-type filters. According to NAFA, these filters remove 35-49.9 percent of particles in the 3-10-micron size range. The pressure differential gauges used were the inclined tube manometer without any gauge oil to accurately read air filter pressure drop.

According to officials, the initial, clean filter static pressure operating at 400-450 feet per minute is 0.15-inch in water gauge (wg). The gasket material on the filter holding frames and air handler doors were deteriorated, and in many instances missing altogether. To replace each filter, officials said a technician had to spend approximately 4-5 minutes to remove and replace the new, clean filter cartridge.


The school wanted to upgrade the filtration efficiency to meet or exceed the filter efficiency required by ASHRAE Standard 62.1, under section 5.9 “Particulate Matter.” School officials also wanted to spend less time installing filters, allowing more time to address other maintenance duties.

The other objective was to keep the HVAC system components hygienically clean and to reduce coil and duct cleaning. Finally, the school also wanted to improve the overall IAQ with higher efficiency air filters.

Several air filter product types were evaluated for:

  • Efficiency/MERV.
  • Documentation/test reports.
  • Construction quality.
  • Initial cost vs. life-cycle cost/operating cost.
  • Labor/installation.

The products selected for the upgrade were 4-inch deep, high-capacity, extended-surface, pleated (MERV 11) air filters, designed to remove 65-79.9 percent of 1-3-micron particles.

According to NAFA, this efficiency level addresses the EPA’s PM 2.5 Standard. It said particulates of 2.5 microns may potentially cause lung infection and possible disease.

According to NAFA, these filters have approximately the same amount of media (26.1 square feet) as the original (MERV 6) 8-inch-deep cartridge filters (29 square feet). The initial clean filter static pressure at 400-450 fpm is 0.21 inch wg, which is a negligible 0.06-inch-wg differential.

According to NAFA, the 4-inch filters were installed in the existing filter-holding frames with new filter latches. Closed-cell neoprene gasket material was installed on the filter-holding frames and doors of the air-handling equipment. NAFA said the time to remove and install the 4-inch filters took approximately 15-20 seconds each, compared with an estimated 4-5 minutes it took for the original 8-inch cartridge types.

Magnehelic® gauges were properly installed on all air-handling units. NAFA said this allowed the technicians to effectively measure, monitor, and manage the air filter changeouts by airflow pressure drop. Having the HVAC technicians and custodial staff successfully complete the NAFA Certified Technician program provided the means for the school to have qualified trained technicians with the skills necessary to maintain the HVAC air filtration system.


Officials at the school said the upgraded filter efficiency and long life cycle of the 4-inch (MERV 11) pleated filters vs. the 8-inch cartridge-type (MERV 6) filters save on labor and associated disposal costs. The higher efficiency filters also keep the ductwork clean, while operating the heating-cooling coils at peak energy efficiency. They said the overall IAQ was also improved with the higher-efficiency pleated filters.

“Products selected by Ken Whidden and Tim Rivers of the Engineering/Maintenance De- partment of the Keefe Technical School can be implemented by other school departments and educational facilities that are looking to improve overall IAQ, equipment efficiency, and system performance,” said Veeck.

“Building owners and facility managers will also save on valuable energy consumption, scheduling air filter changeouts on pressure drop, while providing a safe, clean, and comfortable indoor air environment for all the students and occupants in our school systems today.”

Clean Costs Less

The National Air Filtration Association (NAFA) said it is dedicated to providing training and certification to those involved in providing clean air to building inhabitants. NAFA maintains that, most of the time, the lowest initial cost air filter is not the lowest overall cost air filter when energy, storage, change schedules, and disposal costs are included.

NAFA executive director Alan Veeck said member companies have the skills and information, along with technology and tools, to help school personnel determine the correct filter for the application, the appropriate change schedule, and the training and certification for air filter technicians “that combine to give value and cost savings in most every application.” (The NAFA Website,, provides the location and information of NAFA members.)

“School personnel would do justice to their organization and to the school kids and adults to explore the solutions these companies provide,” said Veeck.

School Ventilation; Air Conditioning, Heating & Refrigeration News, April 21, 2008Review this and other HVACR articles on the Air Conditioning, Heating & Refrigeration News’ Website