Using sheet metal screws in a B vent pipe is an acceptable attachment method. Many manufacturers allow the use of sheet metal screws in the installation of a B vent pipe. The B vent should slide over a galvanized pipe that has already been put into place. This can then be secured with four sheet metal screws. If connecting a single-wall pipe to the B vent, the sheet metal screws will be used to attach the outer wall locking tabs to the single-wall pipe. Fold down the tabs to act as an access panel and secure the pipe in place with one-fourth-inch screws. The B vent cap can then be attached to the pipe.