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<br />structure's lowest floor above the regulatory flood protection elevation. These alternative methods <br />may include the use of stilts, pilings, parallel walls and the like, or above-grade, enclosed areas such as <br />crawl spaces or tuck-under garages. The base or floor of an enclosed area shall be considered above- <br />grade and not a structure's basement or lowest floor if: the enclosed area is above grade on at least one <br />side of the structure; the enclosed area is designed to flood internally and is constructed with flood- <br />resistant materials; and the enclosed area is used solely for parking of vehicles, building access or <br />storage. The above-noted alternative elevation methods are subject to the following additional <br />standards: <br /> <br />(a) Design and certification. The structure's design and as-built condition must be <br />certified by a registered professional engineer or architect as being in compliance with the general <br />design standards of the Minnesota Building Code and, specifically, that all electrical, heating, <br />ventilation, plumbing and air conditioning equipment and other service facilities must be at or above <br />the regulatory flood protection elevation or be designed to prevent floodwater from entering or <br />accumulating within these components during times of flooding. <br /> <br />(b) Specific standards for above-grade, enclosed areas. Above-grade, fully enclosed <br />areas such as crawl spaces or tuck-under garages must be designed to flood internally, and the design <br />plans must stipulate: <br /> <br />1. The minimum area of openings in the walls where internal flooding is to be used <br />as a flood-proofing technique. When openings are placed in a structure's walls to provide for entry of <br />floodwaters to equalize pressures, the bottom of all openings shall be no higher than one foot above <br />grade. Openings may be equipped with screens, louvers, valves or other coverings or devices; <br />provided, that they permit the automatic entry and exit of floodwaters; and <br /> <br />2. That the enclosed area will be designed of flood-resistant materials in <br />accordance with the FP-3 or FP-4 classifications in the Minnesota Building Code and shall be used <br />solely for building access, parking of vehicles or storage. <br /> <br />(2) Basements, as defined in this chapter, shall be subject to the following: <br /> <br />(a) Residential basement construction shall not be allowed below the regulatory flood <br />protection elevation; and <br /> <br />(b) Nonresidential basements may be allowed below the regulatory flood protection <br />elevation; provided, that the basement is structurally dry flood-proofed in accordance with this chapter. <br /> <br />(3) All areas of nonresidential structures, including basements, to be placed below the <br />regulatory flood protection elevation shall be flood-proofed in accordance with the structurally dry <br />flood-proofing classifications in the Minnesota Building Code. Structurally dry flood-proofmg must <br />meet the FP-1 or FP-2 flood-proofmg classification in the Minnesota Building Code and this shall <br />require making the structure watertight with the walls substantially impermeable to the passage of <br />water and with structural components having the capability of buoyancy. Structures flood-proofed to <br />the FP-3 or FP-4 classification shall not be permitted. <br /> <br />146 <br />