ABSTRACT
This chapter focuses on perhaps the most important question to be answered as part of a ventilation-based indoor air quality (IAQ) evaluation: “How much outdoor air is actually being delivered to the building occupants?” It discusses the some basic techniques for determining the outdoor air (OA) quantity that is actually delivered to the occupied areas in a building. These techniques are based on the measurement of the buildup of carbon dioxide concentrations, the decay of sulfur hexafluoride concentrations, and the determination of the supply air (SA) quantity in conjunction with a determination of the %OA in this SA quantity. The use of tracer gas measurements provides a very useful tool in the determination of the OA quantity delivered to the occupied areas of a building. In order to perform the tracer decay method, the equipment required includes a source of the tracer gas, a means of collecting samples of the tracer in the room air, and a tracer gas analyzer.
