NY STATE Uniform Fire Prevention and Building Code
"Section R202 of the 2010 RCNYS:
• The term story is defined as “that portion of a building included between the upper surface of a floor and the upper surface of the floor or roof next above.”
• The term basement is defined as “that portion of a building that is partly or completely below grade.”
• The term grade is defined as “the finished ground level adjoining the building at all exterior walls.”
• The term grade plane is defined as “a reference plane representing the average of the finished ground level adjoining the building at all exterior walls. Where the finished ground level slopes away from the exterior walls, the reference plane shall be established by the lowest points within the area between the building and the lot line or, where the lot line is more than 6 feet (1829 mm) from the building between the structure and a point 6 feet (1829 mm) from the building.”
• The term story above grade is defined as “any story having its finished floor surface entirely above grade . . . .”
In general, a basement (i.e., that portion of a building that is partly or completely below grade) is not a story above grade (i.e., a story having its finished floor space entirely above grade). However, the definition of story above grade includes an exception (hereinafter referred to as the “basement exception”) which provides that a basement will be deemed to be a story above grade if any one or more of the following conditions is satisfied:
• the finished surface of the floor above the basement is more than 6 feet above grade plane,
• the finished surface of the floor above the basement is more than 6 feet above the finished ground level for more than 50 percent of the total building perimeter, and/or
• the finished surface of the floor above the basement is more than 12 feet above the finished ground level at any point.
Homes with Basements
In some cases, a home that has been elevated to comply with the flood-resistant construction requirements of the Uniform Code may still have a basement.6Fvii This portion of this Technical Bulletin will discuss the factors that will determine if the basement in such a home must count as a story above grade.
Based on the definitions quoted at page 2 of this Technical Bulletin, if a space is a portion of a building and is partly or completely below grade, the space is a basement.
If any one or more of the three conditions in the “basement exception” in the definition of story above grade is satisfied, the space is a basement and a story above grade."