302.3.5 Drilling and notching of top plate.
FGC § 302.3.5
When piping is placed in or partly in an exterior wall or interior load-bearing wall, necessitating cutting, drilling or notching of the top plate by more than 50 percent of its width, a galvanized metal tie not less than 0.054 inch thick (1.37 mm) (No. 16 gage) and 1 1/2 inches (38.1 mm) wide shall be fastened across and to the plate at each side of the opening with not less than eight 10d (0.148 inch diameter) nails having a minimum length of 1 1/2 inches (38.1 mm) at each side or equivalent. The metal tie must extend a minimum of 6 inches (152.4 mm) past the opening. See Figure 2308.5.8 of the New York City Building Code. Exception: When the entire side of the wall with the notch or cut is covered by wood structural panel sheathing, additional fastening is not required.
