A Blueprint for IAQ

Sept. 1, 1999
Even though it seems that IAQ is a difficult beast to control, school staff can prevent most IAQ concerns with simple and practical solutions.

More and more educational facility managers and administrators are having to confront indoor air quality (IAQ) issues. It can be a complex problem, involving maintenance practices, new building materials, energy-conservation measures and changes in building use. Further complicating the matter are some of the typical characteristics of educational facilities-high occupant density, tight maintenance budgets and several potential sources of pollution (fine arts, science, vocational/industrial arts, home economics).

Even though it seems that IAQ is a difficult beast to control, school staff can prevent most IAQ concerns with simple and practical solutions.

Setting Goals

In school buildings, managing IAQ is as much a policy issue as it is a technical one. District administrators should set specific goals and provide appropriate resources to meet those goals. The following minimal goals can help to improve air quality:

-Monitor heating, ventilation and air conditioning (HVAC) systems to make sure they operate within initial design parameters and at no less than 5 cfm/outside air (OA) per person under minimum conditions. Ensure appropriate and regular maintenance of all HVAC systems.

-Improve building cleaning procedures and equipment to enhance the effectiveness of ventilation systems.

-Reduce exposure to volatile organic compounds (VOCs) by controlling the type and quantity of cleaning chemicals. During application, purge these chemicals by way of the ventilation system.

-Reduce or eliminate the infiltration of water and other moisture into buildings.

-Provide education and training at all staff levels.

HVAC maintenance

One of the most critical components for good indoor air quality is ongoing maintenance of HVAC systems. Perform the following HVAC maintenance regularly:

-Check the exhaust air quarterly. Use tracer smoke or other means to ensure that air is being exhausted.

-Inspect semi-annually the outdoor air intakes on all air-handling systems, especially unit ventilators. Also, check the outside air and return-air damper, and the calibration of all HVAC controls.

-Annually, spot check the ductwork to determine if it needs cleaning. If access panels for inspection are not available, install them.

-Filters with ASHRAE dust spot efficiency of 30 percent are recommended to ensure that particulates in the return and outdoor air streams are filtered. When upgrading filters, do not restrict the air flow. Change filters quarterly.

-Inspect heating coils annually, and have them professionally cleaned every five to 10 years. Pressure-wash the unit-ventilator coils annually.

-Clean the cooling coils annually, especially on the upstream side of the coil. Also, clean drainage pans/areas annually. Remove, cover up or coat interior fiberglass duct insulation downstream and adjacent to cooling coils. This will prevent microbial problems and allow for easy cleaning.

-Annually, inspect and clean supply fan and air blowers as part of the duct-cleaning process.

-Periodically, monitor ventilation air flows.

Cleaning tips

Studies have shown that quality cleaning can significantly reduce indoor contaminants including dust and dirt, VOCs and microbial spores. Here are some important cleaning points:

-Vacuum carpets daily with a high-efficiency filtering system capable of removing 1-micron-sized particles with 90 percent efficiency.

-On at least an annual basis, preferably semi-annually, clean carpets with hot-water extraction. Dry the carpet within 24 hours with dehumidifiers and floor fans.

-Mop all hard-floor surfaces daily, and damp-wipe horizontal surfaces-desks, computers and cabinets-weekly.

-While using cleaning chemicals, the ventilation system should be operating to ensure that pollutants that may build up are appropriately and immediately purged.

The use of certain building materials, such as sheetrock, ceiling tile and carpet, can lead to moisture intrusion and significant microbial problems. The following steps can help control moisture problems and eliminate microbiological contamination:

-Perform a baseline inspection of the building envelope (walls, roofs, windows and doors), and establish priorities to correct problems.

-Annually evaluate your roofs and building facades, and your replacement and remediation cycle.

-Annually inspect tunnels and crawl spaces to document and repair water infiltration.

Education and training

Education, training and communication are imperative to any program's success. Train the teaching staff to be observant of air quality. Encourage them to report any concerns. Train the custodial staff about the preventive-maintenance steps that will enhance air quality, as well as the effect cleaning and chemical usage can have on the health of building occupants.

The continuing focus on IAQ will require an eclectic approach on the part of school administrators. Working without clear regulation can be difficult, but it can allow for responsible and creative solutions.

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