This supplement to ASCE/SEI 7-22 is a significant revision of the design provisions in Chapter 5 to strengthen building resilience against the flood hazard.
The primary technical updates relative to climate impacts include a new requirement tying flood hazard mitigation design to Risk Category, which is consistent with other environmental hazards in ASCE 7. There are four categories from which a building designer can select based on the intended use of the structure, ranging from the least risk to human life in the event of failure in Risk Category I structures to the greatest risk to human life in the event of failure in Risk Category IV structures. The new provisions require Risk Category II structures and above to use the 500-year floodplain to determine flood loads. Risk Category II structures, the most commonly used category, include one- and two-family buildings, low to medium occupancy businesses, or recreational facilities. Risk Category I structures, including agricultural buildings such as barns and sheds, could still follow 100-year flood provisions.