§ 722.4.2 — § 722.4.2

722.4.2 Multi-wythe walls.

BC § 722.4.2

The fire-resistance rating for walls or partitions consisting of two or more dissimilar wythes shall be permitted to be determined by the formula: R = (R 10.59 + R 20.59 + . . . + R n0.59 ) 1.7 (Equation 7-11) where: R = The fire-resistance of the assembly (hours). R 1 , R 2 and R n = The fire-resistance of the individual wythes (hours). Values for R n0.59 for use in Equation 7-11 are given in Table 722.4.1(3).