Description of ASHRAE's Proposed Air Tightness Standard

Because the load due to air infiltration typically accounts for onethird of space conditioning loads, ASH RAE (American Society of Heating, Refrigerating and Air-conditioning Engineers) is in the process of writing a standard which addresses the maximum leakage associated with good construction. This standard, SPC 119P, is a link between ASH RAE 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 119 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 will present the background around SPC 119P, indicate a proposed form that the standard may take, and present some of the rationale behind it.