SIGNIFICANT DEVELOPMENTS HAVE OCCURRED over the 13 years since this chapter was originally published. That being said, the industry is continuing a significant amount of development activity in codes and standards. The update of the chapter maintains the same format as the original chapter. The 1994 chapter was reviewed and revised as well as updated. Much of the chapter's original content remains pertinent and was retained. New information is added. Of special interest are a number of new standards related to the analysis of building systems for moisture performance and standards for system installation or performance testing. There has also been increased focus on climate-based guidelines and recommendations.