722.2.4.1.2 Concrete strength greater than 12,000 psi.
BC § 722.2.4.1.2
For columns made with concrete having a specified compressive strength, f'c , greater than 12,000 psi (82.7 MPa), for fire-resistance ratings of 1 hour to 4 hours the minimum dimension shall be 24 inches (609.6 mm).













