Mathematical Analytics of Ventilation Requirements: Two Plus Two Does Not Equal Four PDF

Consensus on ventilation requirements has been difficult and, at times, extremely contentious. Although most of the controversy can be attributable to philosophical differences of opinion, there are some technical issues that have been a key part of the consensus discussion. In some cases, the mathematical expressions of the various ventilation requirements have had their own set of issues and controversies. These issues include: infiltration credit, unbalanced vs. balanced fans, and discounting of intermittent fans. This paper presents the scientific and analytical bases of the various mathematical forms and positions taken. Emphasis will be on the calculation framework of ANSI/ASHRAE 62.2-2004, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings, although other ASHRAE Standards, such as ANSI/ASHRAE 62.1, Ventilation for Acceptable Indoor Air Quality, and other reference materials are included in the comparative analysis. Conceptual reasoning behind the various mathematical expressions is presented along with examples demonstrating compliance. Counterintuitive notions such as the sub-additive effect mentioned in the title are explained. It is concluded that lifting the mystery behind the calculations can increase the understanding for a wider base of users, which, in turn, could result in clarifications and refinements in the standards themselves.

IAQ 2007 Conference held in Baltimore, Maryland, October 14-17, 2007

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