You are here:
POSSIBLE ROLE OF INDOOR RADON REDUCTION SYSTEMS IN BACK-DRAFTING RESIDENTIAL COMBUSTION APPLIANCES
HENSCHEL, D. POSSIBLE ROLE OF INDOOR RADON REDUCTION SYSTEMS IN BACK-DRAFTING RESIDENTIAL COMBUSTION APPLIANCES. INDOOR AIR. Wiley InterScience, Silver Spring, MD, 7(3):206-14, (1997).
The article gives results of a computational sensitivity analysis conducted to identify conditions under which residential active soil depressurization (ASD) systems for indoor radon reduction might contribute to or create back-drafting of natural draft combustion appliances. Parameters varied were: house size, normalized leakage area, exhaust rate of exhaust appliances other than the ASD system, and the amount of house air exhausted by the ASD system. Even with conservative assumptions, it is predicted that ASD systems will not contribute to or create back-drafting in most of the U.S. housing stock. Only at normalized leakage areas lower than 3 to 4 sq cm (at 4 Pa) per sq m of floor area would ASD contribute to back-drafting, even in small houses at high ASD exhaust rates (compared to a mean of over 10 sq cm/sq m determined from data on over 12,000 U.S. houses). However, even with more forgiving assumptions, it is predicted that ASD systems can contribute to back-drafting in some fraction of the housing stock -- houses tighter than about 1 to
2 sq cm/sq m -- even in large houses at minimal ASD exhaust rates. Thus, without data on the leakiness of the house shell, it is not possible to use parameters such as house size or ASD system flow rate to reliably estimate the risk that an ASD system might contribute to back-drafting in a given house. Extensive back-draft tests would be needed.