N.Y.C. Admin. Code § BC 2514: Section BC 2514: Reinforced Gypsum Concrete

2514.1 General.

Reinforced gypsum concrete shall comply with the requirements of ASTM C 317 and ASTM C 956.

2514.2 Minimum thickness.

The minimum thickness of reinforced gypsum concrete shall be 2 inches (51 mm) except the minimum required thickness shall be reduced to 1 1/2 inches (38 mm), provided the following conditions are satisfied:

1. The overall thickness, including the formboard, is not less than 2 inches (51 mm).

2. The clear span of the gypsum concrete between supports does not exceed 33 inches (838 mm).

3. Diaphragm action is not required.

4. The design live load does not exceed 40 pounds per square foot (psf) (1915 Pa).

2514.3 Limitations of use.

Reinforced gypsum concrete shall not be used where exposed directly to the weather or where subject to frequent or continuous wetting. Precast units shall be protected by coverings or coatings from the weather and from contact with moisture during shipment and during storage at the work site.