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FACTORS AFFECTING AIR EXCHANGE IN TWO HOUSES
Citation:
HowardReed, C, L A. Wallace, AND W R. Ott. FACTORS AFFECTING AIR EXCHANGE IN TWO HOUSES. Presented at ISEE/ISEA '99 Conference, Athens, Greece, September 5-8, 1999.
Description:
Air exchange rate is critical to determining the relationship between indoor and outdoor concentrations of hazardous pollutants. Approximately 150 air exchange experiments were completed in two residences: a two-story detached house located in Redwood City, CA and a three-story town home located in Reston, VA. A continuous monitor (Bruel & Kjaer) measured the decay of sulfur hexafluoride over periods of 5 to 20 hours. Different seasons, temperatures, central fan usage, and window opening configurations were studied. Each experiment included a measurement of the air exchange rate first with all exterior doors and windows closed, then with a window open to a specific width. For 50 experiments, air exchange rates were measured in multiple locations of the homes. For both homes, air exchange rates measured during closed conditions (i.e., no exterior doors or windows open) ranged from 0.25/hr to 1.0/hr. For the Reston home, an 8 F increase in the difference between indoor and outdoor temperature led to a 0.1 /hr increase (R2 = 0.43) in the closed condition air exchange rate. A more significant impact on air exchange was achieved by opening a single window 0.5 to 20 inches. For example, a 0.1/hr increase in air exchange was achieved by opening a single window 1 inch. This response was observed to be linear up to 5 inches in. both homes, after which an upper limit asymptote was reached. Air exchange rates were also measured at different locations to determine the extent of mixing within each house. Results showed multiple compartments existed for conditions of increased indoor/outdoor temperature difference and when a single window was opened. A three compartment mass balance model was used to investigate the Reston results.
This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.