International Green Construction Code
The International Green Construction Code (IgCC) is an effort of the International Code Council aimed at creating a new green overlay code for the ICC’s suite of I-Codes. The IgCC includes requirements for a range of issues pertinent to sustainability, including a substantial portion dedicated to energy efficiency.
As an “overlay” code, the IgCC works in combination with other underlying codes including the 2012 International Energy Conservation Code and the entire suite of I-Codes.
NBI became involved in the IgCC development process during the developmental meetings that produced the first public version of the IgCC (PV-1). As an advanced green code intended for more forward-thinking jurisdictions and institutions, NBI sees the IgCC as a forum to introduce new concepts that might be too progressive or revolutionary for base energy codes like the IECC. This in turn provides the opportunity to both refine those concepts and give them the exposure that can ready them for the next revision of IECC and other national standards. Through the development and hearing process, NBI focused on a number of key issues including metering, energy metrics and outcome-based compliance.
Key Areas for Energy Performance in IgCC
Metering – Policy makers, owners, occupants, building scientists and the real estate market all need more data about energy performance. One way that codes can support this need is by ensuring that buildings are constructed in such a way that energy usage data can be easily obtained and will have maximum utility. NBI worked extensively to help craft language for the IgCC that will require whole building and useful sub-metering and require that buildings be wired and piped in a way that will make metering and sub-metering easier and more cost effective.
Energy Metrics – In collaboration with AIA, NBI proposed the use of zEPI (Zero Energy Performance Index) in the IgCC. zEPI is a scale that relates performance levels to a static baseline of the average performance of the building stock at the turn of the millennium. zEPI enables individual buildings, portfolios, entire building stocks and code performance levels to be compared to each other with a common baseline.
Outcome-Based Compliance – In traditional energy codes, buildings demonstrate compliance either through meeting a prescriptive list of building features or by using modeling software to demonstrate an equivalent level of performance. Both these compliance paths are based on proxies for actual energy outcomes. With an outcome-based compliance path, buildings demonstrate compliance not through a proxy, but through actual energy outcomes. This option would provide significantly more flexibility. An important element of adding outcome-based compliance to existing codes is rearranging the energy chapter to formalize a multiple compliance path structure.
IgCC Development & Comments
NBI worked with several organizations to submit 10 comments related to our interest in metering, metrics and outcome-based compliance for the current development cycle of the IgCC.