Description of ASHRAE's proposed air tightness standard.

ASHRAE is preparing a standard which addresses the maximum air leakage associated with good construction. This standard, 119P, links Standard 90, which addresses energy conservation in new residential construction, and Standard 62, which specifies the minimum acceptable ventilation to achieve adequate indoor air quality. Within Standard 119P there is currently a classification scheme that groups building tightness into categories depending on envelope leakage, floor area and building height. In addition to being used for this residential leakage standard, this classification scheme is intended to be used to label the tightness of any building, residential or commercial, new or existing. This report presents the background around Standard 119P, indicates a proposed form that the standard may take, and presents some of the rationale behind it.