When new building code requirements require high performance and innovation incentives, such as those found in green building rating systems, significant confusion and some building failure will ensue. This is the current situation that designers and contractors are facing in wall system air barrier design and performance.
Significant in 2012 was the issuance of the International Green Construction Code. This provided a vehicle for codifying many elements of the U.S. Green Building Council LEED rating systems and ASHRAE standards that have been issued over the last decade. (Most of them have been released in just the last two years.)