- Floor assemblies located directly over a space protected by an approved automatic sprinkler system.
- Floor assemblies located directly over a crawl space not intended for storage or fuel-fired appliances.
- Portions of floor assemblies shall be permitted to be unprotected where the aggregate area of the unprotected portions does not exceed 80 square feet (7.4 m2) per story.
- Wood floor assemblies using dimension lumber or structural composite lumber equal to or greater than 2-inch by 10-inch (50.8 mm by 254 mm) nominal dimension, or other approved floor assemblies demonstrating equivalent fire performance.
For members having a single tendon or more than one tendon installed with equal concrete cover measured from the nearest surface, the cover shall be not less than that set forth in Table 721.1(1). For members having multiple tendons installed with variable concrete cover, the average tendon cover shall be not less than that set forth in Table 721.1(1), provided that:
- The clearance from each tendon to the nearest exposed surface is used to determine the average cover.
- The clear cover for individual tendons shall not be less than one-half of that set forth in Table 721.1(1). A minimum cover of 3/4 inch (19.1 mm) for slabs and 1 inch (25 mm) for beams is required for any aggregate concrete.
- For the purpose of establishing a fire-resistance rating, tendons having a clear covering less than that set forth in Table 721.1(1) shall not contribute more than 50 percent of the required ultimate moment capacity for members less than 350 square inches (0.226 m2) in cross-sectional area and 65 percent for larger members. For structural design purposes, however, tendons having a reduced cover are assumed to be fully effective.