Abstract
A novel procedure has been developed to measure, under field conditions, the portion of outdoor air that is supplied to individual building occupants. The method is simpler to use than measurement of ventilation efficiency and ventilation effectiveness procedures. This method also takes into consideration factors associated with office design that can have a significant effect on this parameter. The method is based on the constant release of tracer gas into the outdoor air introduced into a ventilation system and its measurement, at steady state, at individual work stations. The values obtained are called outdoor air supply indexes (OASls) to differentiate them from those found with the measurement of ventilation efficiency or effectiveness, which refer to the performance of a mechanical ventilation and air-distribution system. The results indicate that the type of diffuser, office, partition, and return air inlet and their position relative to each other can have a dramatic effect on the amount of outdoor air supplied to individual work stations. OASI values obtained also correspond remarkably well with a wide array of environmental parameters measured and the complaints made by building occupants. The test takes 30 min to complete and requires little preparation and skill. It is anticipated that the results obtained with the method reported here will assist in resolving indoor air quality problems in many modern office buildings.