The proposed changes open for review in Addendum r of ANSI/ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality, focus on the indoor-air-quality (IAQ) procedure, which is a performance-based approach to compliance with the standard, and allows designers to adjust the ventilation requirements for a building or space based on performance factors that are unique to the building. These performance factors could include the use of low-emitting materials in the space or the known presence of a contaminant source.

The first public-review draft of Addendum r removed a method of complying with the IAQ procedure by designing the ventilation system in the same way as an existing successful building. Based on public-review comments, this approach was put back into the standard, but with new restrictions. These include a requirement that a mass-balance analysis of the building's air quality be performed in every case. This will require that the designer identify contaminants of concern for every building or space where the IAQ procedure is used, along with associated concentration or exposure limits.

The proposed addendum is open for public review from Sept. 11 until Oct. 26. Standard 62.1 sets minimum ventilation rates and other requirements for commercial and institutional buildings.

Also open for public review during the same time period is proposed addendum g, which would add information on using demand controlled ventilation systems. Coverage of DCV systems in the standard is not yet comprehensive, but this addendum provides needed clarifications on the issue.

To view a copy of the addenda open for public review, go to www.ashrae.org/publicreviews. Copies of public review drafts are only available during public review periods.