ABSTRACT
The evaluation of the performance of a ventilation system is primarily concerned with the quantity of outdoor air delivered to the building occupants. This quantity of outdoor air can be expressed in several different units. The use of the units reflect the fact that the supply air is made up of a mixture of both the outdoor air for ventilation and air that is recirculated from the building which are then combined to achieve a total volume needed to facilitate thermal regulation. The importance of the ventilation rate evaluation criterion is its recognition of the fact that people are not the only interior source of air contaminants in the building, and that the furnishing and building components also have the potential to be sources of air contaminants. In actual practice, the percentage of outdoor air can vary from 0% all the way up to 100%, depending on the design, installation, and operation of the equipment.
