CH-99-19-3 -- The Use of Multipoint Monitoring as a Tool for Commissioning Buildings for IAQ PDF

One basic goal of the commissioning process is to make sure that the HVAC system is functioning as intended. In particular, it is intended that the HVAC system not only provide adequate ventilation for the building occupants but also achieve adequate pressurization of the occupied spaces to prevent the infiltration of unconditioned air. One technique for evaluating the performance of the HVAC system in these areas is to use continual, multipoint monitoring of carbon dioxide, carbon monoxide, and dew point at selected locations in the building and the HVAC system. Specific performance evaluations provided by multipoint continual monitoring of these parameters include a determination of the amount of outdoor air delivered to the occupants for ventilation, an evaluation of the uniformity of the amount of ventilation provided to the different locations served by a given air-handling unit (AHU), an evaluation of the adequacy of the system operation in completely purging the building overnight of air contaminants from the previous day's occupancy, the identification of the infiltration of unconditioned air into occupied spaces, the identification of the magnitude and frequency of reentrainment of building exhaust, and the identification of the magnitude and frequency of the introduction of vehicle exhaust from nearby traffic. Specific examples of all of these performance evaluations are presented and discussed in this paper. In addition, these ongoing evaluations of system performance can not only identify the presence of problems but can also evaluate the effectiveness of mitigation efforts to correct and eliminate these problems. The use of continual, multipoint monitoring of these parameters, therefore, can yield improved indoor air quality (IAQ) in buildings from initial occupancy throughout their useful life.

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