PERFORMANCE: Codes & Standards
Energy & Cost
Codes & Standards
International Green Construction Code and ASHRAE Standard 189
In order to provide adoptable and enforceable baselines for green construction, the International Code Council (IECC) and ASHRAE have established the International Green Construction Code (IgCC) and ASHRAE/USGBC/IES Standard 189.1. These can be adopted by jurisdictions in addition to conventional building codes.
International Green Construction Code (IgCC) Public Version 2.0
Smaller buildings have more compliance options, including a prescriptive path. Regardless of the compliance option, fenestration must comply with the mandatory air leakage limits of the 2012 IECC. For fenestration and other building envelope systems, the prescriptive path requires that the 2012 IECC requirements are exceeded by at least 10%. The prescriptive path also requires permanent shading devices for fenestration facing east west and south.
ASHRAE/USGBC/IES Standard 189.1-2009
The prescriptive option limits vertical fenestration area to less than 40% of the gross above-grade wall area. Office spaces and classrooms require a minimum effective aperture, which is the product of vertical fenestration area and visible transmittance. In climate zones with substantial cooling loads, the area of west- and east-oriented vertical fenestration is limited relative to north- and south-oriented fenestration, and permanent shading devices are required for fenestration facing east west and south.
The prescriptive option limits skylight area to 5% of the gross roof area. . In some larger spaces with high ceilings, the code requires a minimum skylight area for daylighting.
SHGC requirements for vertical fenestration are adjusted where shading by permanent projections exceeds the required minimum. Where skylights are integrated into daylighting design, SHGC requirements do not apply. For skylights with plastic and curb, different requirements apply than for skylights with glass or without curb.
Mandatory air leakage limits depend on the fenestration type. For windows, sliding doors, swinging doors and skylights, the maximum air leakage rate is 0.4 cfm/ft2.