The intent of the credit is to "Provide capacity for indoor air quality (IAQ) monitoring to help sustain long-term occupant comfort and well-being". The requirements are "Install a permanent carbon dioxide (CO2) monitoring system that provides feedback on space ventilation performance in a form that affords operational adjustments". The requirements portion of the credit language then refers to complying with ASHRAE 62-2001 Appendix C. The reference manual Design Approach section of EQc1 provides a suggested approach to obtaining the credit and in our opinion incorrectly states that "Indoor CO2 concentrations must be compared to outdoor CO2 concentrations to determine the differential point at which ventilation rates should be adjusted". Our understanding is that credits are awarded based on the Credit Intent and the stated Requirements contained in the credit language. The reference guide plays a valuable role in helping practitioners apply the principles but does not override the specific credit language. Previous credit interpretations have maintained the requirement for outside CO2 sensor based on the Design Approach contained in the reference guide but not the specific requirements of the credit. The specific requirements of the credit are "Install a permanent carbon dioxide (CO2) monitoring system that provides feedback on space ventilation performance in a form that affords operational adjustments". An outside sensor is not required to accomplish this requirement. The second requirement is to meet ASHRAE 62-2001 Appendix C. Appendix C provides guidance and recommendations on CO2 concentrations including concentration levels above outside conditions to maintain satisfactory conditions for bioeffluents (body odor) dilution, typical range of outdoor CO2 concentrations, and fresh air flow rates required as a function of physical activity, none of which require the installation of an outside CO2 sensor. Outside CO2 concentrations in the area of the project have fluctuated less than 75 PPM over the last 10 years based on several hundred indoor quality studies performed by members of our firm during this period. The fluctuations observed can be attributed to proximity to carbon dioxide production activities such as vehicle traffic, electrical generation, or other forms of combustion or contaminate sources. While outdoor ambient CO2 fluctuations exist, they are generally minor and represent negligible impact on the volume of fresh air introduced into the building. Buildings are designed for a maximum ventilation rate based on occupant load. The ventilation system fresh air volume can be fluctuated based on CO2 concentrations in the building. This is our understanding of the intent of EQc1. The designer established the ventilation rate on the requirements in ASHRAE 62 based on the type of occupant activities. These rates are related to CO2 levels based on assumptions of outdoor CO2 levels in ASHRAE 62 allowing energy savings from reduced ventilation rates when building occupant population is less than peak design. As such the standard does not require outdoor CO2 sensing because the design ventilation maximum is fixed and cannot be changed by an outdoor CO2 sensor. The reference to "above outdoor levels" contained in the standard is to alert the designer to consider ambient CO2 levels in establishing the maximum ventilation rate, not as a requirement for an outside CO2 sensor. The population of occupants in the building can be monitored and controlled through the building automation system by a CO2 monitoring system measuring only interior conditions. We are requesting the USGBC clarify that the EQc1 Intent and Requirements contained in the credit language are the standard that must be met for this credit and, based on the specific requirements of the credit language including ASHRAE 62 Appendix C, acknowledge that an outside sensor is not required thus correct the 9/8/2004 CIR.