47.5 MB - The Whole Building Design Guide

General limitations to building codes include the following:m Because codes are adopted and enforced on the local orState level, the authority having jurisdiction has the power toeliminate or modify wind-related provisions of a model code,or write its own code instead. In places where importantwind-related provisions of the current model code are notadopted and enforced, critical facilities are more susceptibleto wind damage. Additionally, a significant time lag often existsbetween the time a model code is updated and the timeit is implemented by the authority having jurisdiction. Buildingsdesigned to the minimum requirements of an outdatedcode are, therefore, not taking advantage of the currentstate of the knowledge. These buildings are prone to poorerwind performance compared to buildings designed accordingto the current model code.m Adopting the current model code alone does not ensure goodwind performance. The code is a minimum tool that shouldbe used by knowledgeable design professionals in conjunctionwith their training, skills, professional judgment, and the bestpractices presented in this manual. To achieve good windperformance, in addition to good design, the constructionwork must be effectively executed, and the building must beadequately maintained and repaired.m Critical facilities need to perform at a higher level thanrequired by codes and standards. See Section 1.3 onperformance based design.IBC 2006: The 2006 edition of the IBC is believed to be a relativelyeffective code, provided that it is properly followed andenforced. Some limitations of the 2006 IBC have, however, beenidentified:m With respect to hurricanes, the IBC provisions pertainingto building envelopes and rooftop equipment do notadequately address the special needs of critical facilities.For example: (1) they do not account for water infiltrationdue to puncture of the roof membrane by missiles; (2)they do not adequately address the vulnerabilities of brittleroof coverings (such as tile) to missile-induced damage3-20 MAKING CRITICAL FACILITIES SAFE FROM High Wind