IAQ procedure

Chad, could you provide more information on the air purification units specified?

We have been wondering the same thing, Chad. We are located in Texas, where humidity is also (usually) a problem, and our project team has data that shows schools that used the IAQ Procedures are outperforming schools that used the Ventilation Rate Procedure in terms of indoor air quality. Results were measured by monitoring test scores and asthma inhaler use - the school using the IAQ Procedure had significantly reduced inhaler use and significantly higher test scores than the school using the Ventilation Procedure.

The ASHRAE 62.1-2007 User's Manual, p. 6-43, actually states, "The IAQP may also be used to achieve better air quality than the VRP (lower contaminant levels and/or higher perceived acceptabilty) with or withiout increasing first cost or maintenance cost." Yet LEED 2009 prescribes the Ventilation Rate Procedure, and the draft LEED 2012 prerequisite specifically prohibits using the IAQ Procedure.

Does anyone know the reason for this? Why does LEED prohibit using the IAQ Procedure?

Just found this credit interpretation ruling, which was published in 2007. However, please note, according to the CIR database, this ruling does NOT apply to LEED 2009 rating systems:

"LEED Interpretation
MPR/Prerequisite/Credit: IEQp1: Minimum Indoor Air Quality Performance
Posting Date: 5/15/2007
ID Number: 5053
Primary Rating System: New Construction v2.2

The CIR is inquiring if the IAQ Procedure, as described in Section 6.3 ASHRAE Standard 62.1-2004, can be used in place of the Ventilation Rate Procedure of the same Standard to document compliance with the requirements of this prerequisite. The Ventilation Rate Procedure methodology found in Section 6.2 of ASHRAE 62.1-2004 is the required approach in EQp1, since it is prescriptive and therefore more straightforward to apply. The Ventilation Rate Procedure is based on contaminant sources and source strengths that are typical for common space types listed in the Standard. The Indoor Air Quality (IAQ) Procedure methodology found in Section 6.3 of ASHRAE 62.1-2004 and proposed by this project team is performance-based and relies on identification of contaminants of concern, sources for those contaminants, concentration targets, and perceived acceptability targets. The project-specific nature of the IAQ procedure methodology makes it less commonly used and more difficult for USGBC to evaluate. Therefore USGBC cannot allow its use to show compliance with LEED NC v2.2 EQp1. Please note that the intent behind this prerequisite is to encourage designers to take the most stringent and conservative prescriptive approach to providing fresh air. The language of the prerequisite asks designers to compare the rates recommended under Ventilation Rate Procedure with that required by their local code and to pick the most stringent. As for the project team's legitimate concern with energy efficiency, the "additive" Ventilation Rate Procedure adopted in the ASHRAE Standard 62.1-2004 reflects concerns for energy consumption with elevated ventilation rates. The recommended rate under the Ventilation Rate Procedure in ASHRAE Standard 62.1-2004, in many important occupancy types and projects can result in lower ventilation rates than those required by the earlier version of the Standard - Standard 62.1-2001."