"This standard establishes guidelines to estimate the frequency of occurrence and the magnitude of parameters associated with tornadoes@ hurricanes@ and other extreme winds at nuclear power reactor sites. It treats data and methods to determine wind speed@ characteristics of the wind field@ atmospheric pressure change@ rate of pressure change@ and missile characteristics. It does not treat the forces on structures that result from these physical phenomena. For a site within the contiguous United States@ the standard presents the design basis tornado and tornado-generated missile characteristics and a recommended methodology for determining non-tornadic extreme winds that a nuclear power plant be designed to withstand in order to assure that public health and safety will be maintained as required in the Code of Federal Regulations@ Title 10 ""Energy@"" Part 50@ ""Domestic Licensing of Production and Utilization Facilities@"" Appendix A@ Criteria 2 and 4 [1].1 Tornadoes have occurred in all states covered by this standard. The standard does not address the determination of the design basis tornado@ other extreme windspeeds for sites located in Alaska@ Hawaii@ and Puerto Rico or over the oceans. Such determinations should be evaluated on a case-by-case basis. Additionally@ the standard does not identify the structures@ systems@ and components that should be designed to withstand the effects of the design basis windspeeds and remain functional; nor does it treat the structural design requirements for protection from these winds.2 1Numbers in brackets refer to corresponding numbers in Section 5@ References. 2U.S. NRC Regulatory Guide 1.76@ ""Design Basis Tornado for Nuclear Power Plants"" and its supporting document WASH-1300 were issued in 1974. The analyses and conclusions contained in ANSI/ANS-2.3-1983 are felt to represent the current state of knowledge on tornado and extreme wind characteristics."