Sustainable Building Technical Manual - Etn-presco.net

VENTILATION CONTROL FACTORS AFFECTING IAQFigure 6dling system. These devices monitor and regulate the amount of outdoor and recirculatedair needed to provide minimum ventilation rates and adequate air quality.– Install a high-efficiency air filtration system to remove particles of airborne dustfrom the outside air prior to distribution through the building’s HVAC system. Thefiltration system should consist of two filters. The second or final filter should be 85or 95 percent efficient or should be a HEPA filter.– Either encapsulate fibrous acoustical insulation that is located inside the air-handlingunits, ducts, and variable-air-volume (VAV) boxes, or remove any exposed insulation.These fibers tends to trap dirt that provides a rich nutrient base for microbes.– Design the HVAC system to provide adequate ventilation and appropriate temperatureand humidity for human comfort in accordance with building codes andASHRAE standards and guidelines. 2 6 Within certain limits only, increased ventilationmay reduce the prevalence of MVOCs in indoor air. 27– Carefully design the HVAC system controls to allow the building operator to respondquickly to comfort problems and ventilation deficiencies by providing a buildingcontrolsystem with local controls (override switches and timers) where possible.– Consider the use of an outdoor-air-economizer system. An air-economizer systemenables the building operator to use the energy management system to vary thequantity of outside air brought into the building above minimum ventilation levels.This outside air can be used to maintain the required inside air temperature withoutuse of the refrigeration cycle or recirculated air. With the refrigeration equipmentturned off, energy is saved. The higher rate of outside air also improves ventilationconditions. Care should be taken with regard to humidity buildup.– Install dedicated local-air exhaust systems vented to the outside, separate from thegeneral exhaust system, in spaces that house specific contaminant sources, such askitchens, janitorial closets, bathrooms, and copy rooms. Similarly, consider the viabilityof separate HVAC systems in buildings that support multiple uses.– Consider the use of positive building pressurization in warm, humid climates tolimit the infiltration of moist, hot outside air into the building interior. This will