IBC Design 721.1(3) 29-1.1

2-Hour Fire Rated Channel-shaped 18 gage steel joists (minimum depth… — Base layer 5/8" Type X gypsum board applied…

IBC Table 721.1(3), Item 29-1.1: Channel-shaped 18 gage steel joists (minimum depth 8") spaced a maximum 24" o.c. supporting tongue-and-groove wood structural panels (nominal minimum 3/4"-thick) applied perpendicular to framing members. Structural panels attached with 1-5/8" Type S-12 screws spaced 12" o.c.. Ceiling: Base layer 5/8" Type X gypsum board applied perpendicular to bottom of framing members with 1-1/8" Type S-12 screws spaced 12" o.c. Second layer 5/8" Type X gypsum board attached perpendicular to framing members with 1-5/8" Type S-12 screws spaced 12" o.c. Second layer joints offset 24" from base layer. Third layer 5/8" Type X gypsum board attached perpendicular to framing members with 2-3/8" Type S-12 screws spaced 12" o.c. Third layer joints offset 12" from second layer joints. Hat-shaped 7/8-inch rigid furring channels applied at right angles to framing members over third layer with two 2-3/8" Type S-12 screws at each framing member. Face layer 5/8" Type X gypsum board applied at right angles to furring channels with 1-1/8" Type S screws spaced 12" o.c. Minimum slab thickness — 2-hr: Varies". Minimum ceiling thickness — 2-hr: 3-3/8". Prescriptive assembly from the adopted building code — see table footnotes for conditions.