FEMA's Technical Bulletin (TB) 9, Design and Construction Guidance for Breakaway Walls Below Elevated Buildings Located in Coastal High Hazard Areas (FEMA, 2008), provides guidance on the National Flood Insurance Program (NFIP) regulations concerning the design and construction of breakaway walls beneath elevated buildings in Coastal High Hazard Areas (Zones V, VE, and VI-V30). TB 9 presents three design methods consistent with NFIP regulations: a prescriptive design approach, a simplified design approach and a performance-based design approach.
Additionally, Section 2.3.5 of FEMA P-55, Coastal Construction Manual (2011), discusses enclosures (including breakaway walls) and the unique situation they create in coastal construction. Check with the local jurisdiction for additional information on breakaway walls.
The FEMA floodplain management Web site also contains information on breakaway walls.