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Guidelines for maintaining indoor air quality in schools with HVAC air cleaning systems are provided in this document. Information is offered on the importance of air cleaning, sources of air contaminants and indoor pollutants, types of air cleaners and particulate filters used in central HVAC systems, vapor and gas removal, and performance standards for air filters. Tips for upgrading the cost effectiveness of air filters and for maintaining and purchasing them are also provided. Three figures and three tables are included. (LMI)

Fans, motors, coils, and other control components enable a heating, ventilating, and air-conditioning (HVAC) system to function smoothly. An explanation of these control components and how they make school HVAC systems work is provided. Different systems may be compared by counting the number of controlled devices that are required. Control systems are categorized according to their means of data processing, transmission, and power source: pneumatic, electric, electronics, direct digital, and self-powered. Likewise, the HVAC system is composed of various components: sensors, controllers, actuators (the system's power elements), and controlled devices, (e.g., dampers, valves, and speed regulators). All of these control elements work together to form a control loop. An overview of HVAC systems controls is offered, which focuses on unit ventilators, variable air volume systems, rooftop air conditioning, and supplemental systems. Monitoring the HVAC is also important, and methods such as multiple location supervision are explored. It is suggested that control system maintenance is another important component of any HVAC system, which entails the inventorying of tools and parts. Some control problems that may affect IAQ are provided. (Contains four figures, six references, and a glossary of terms.) (RJM)

To help maintain good indoor air quality (IAQ) in schools, guidance for the development and implementation of an effective program for maintenance and operation of heating, ventilating, and air-conditioning (HVAC) systems are discussed. Frequently, a building's occupants will complain about IAQ when the temperature or humidity are at uncomfortable levels. Such extremes in humidity or temperature can lead to respiratory distress and other problems. To manage IAQ, facilities managers must take the lead and ensure that an effective plan is in place for dealing with HVAC maintenance and other matters. Such plans usually begin with an IAQ profile, which includes an audit of the HVAC and related systems. Documentation is an important component of the plan, as is ensuring that all personnel are properly trained. HVAC commissioning, in which performance and design are verified using computerized controls to monitor the HVAC system, are other vital aspects of an HVAC plan. When such plans are not in place, or even when plans fail, some of the consequences for IAQ include inadequate ventilation, malfunctioning controls, excessive humidity, odors, and irritating vapors. (Contains 4 figures and 18 sources for further information.) (RJM)

Although poor air quality in a school can have multiple causes, the heating, ventilating, and air-conditioning (HVAC) system plays a major role. Suggestions that architects, facilities managers, school board members, and administrators can use in selecting HVAC systems are discussed. Focus is on the performance criteria for classroom systems, and includes temperature and humidity ranges, indoor air quality, energy use, operation and maintenance, simplicity, staffing and standardization, reliability, flexibility, vandal proofing, and capital cost. Detailed descriptions of the kinds of systems used for classrooms are also discussed, such as the use of unit ventilators, variable air volume systems, single zone systems, multizone units, water source heat pumps, and separate ventilation air systems. The advantages of each of these systems are presented. Other considerations facing decision makers include choosing between mechanical or natural ventilation, and figuring ways in which building design, climate, and capital costs will affect such decisions. Likewise, school officials must consider the specifics of location, architecture, use, and management of the facility. To achieve the performance objectives of any HVAC system, requires a balancing of air and water flows, testing performance, documentation, and using trained operating personnel. (Contains five illustrations and nine references.) (RJM)