DOE OSTI2010
This report considers the question of whether the California Energy Commission should incorporate the ASHRAE 62.1 ventilation standard into the Title 24 ventilation rate (VR) standards, thus allowing buildings to follow the Indoor Air Quality Procedure. This, in contrast to the current prescriptive standard, allows the option of using ventilation rate as one of several strategies, which might include source reduction and air cleaning, to meet specified targets of indoor air concentrations and occupant acceptability. The research findings reviewed in this report suggest that a revised approach to a ventilation standard for commercial buildings is necessary, because the current prescriptive ASHRAE 62.1 Ventilation Rate Procedure (VRP) apparently does not provide occupants with either sufficiently acceptable or sufficiently healthprotective air quality. One possible solution would be a dramatic increase in the minimum ventilation rates (VRs) prescribed by a VRP. This solution, however, is not feasible for at least three reasons: the current need to reduce energy use rather than increase it further, the problem of polluted outdoor air in many cities, and the apparent limited ability of increasing VRs to reduce all indoor airborne contaminants of concern (per Hodgson (2003)). Any feasible solution is thus likely to include methods of pollutant reduction other than increased outdoor air ventilation; e.g., source reduction or air cleaning. The alternative 62.1 Indoor Air Quality Procedure (IAQP) offers multiple possible benefits in this direction over the VRP, but seems too limited by insufficient specifications and inadequate available data to provide adequate protection for occupants. Ventilation system designers rarely choose to use it, finding it too arbitrary and requiring use of much non-engineering judgment and information that is not readily available. This report suggests strategies to revise the current ASHRAE IAQP to reduce its current limitations. These strategies, however, would make it more complex and more prescriptive, and would require substantial research. One practical intermediate strategy to save energy would be an alternate VRP, allowing VRs lower than currently prescribed, as long as indoor VOC concentrations were no higher than with VRs prescribed under the current VRP. This kind of hybrid, with source reduction and use of air cleaning optional but permitted, could eventually evolve, as data, materials, and air-cleaning technology allowed gradual lowering of allowable concentrations, into a fully developed IAQP. Ultimately, it seems that VR standards must evolve to resemble the IAQP, especially in California, where buildings must achieve zero net energy use within 20 years.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗