A connection between a vent pipe and a vent stack or stack vent shall be made at least 6 inches (150 mm) above the flood level rim of the highest fixture served by the vent, and 42 inches (1067 mm) minimum above finished floor. Horizontal vent pipes forming branch vents, relief vents or loop vents shall be at least 6 inches (150 mm) above the flood level rim of the highest fixture served and 42 inches (1067 mm) above finished floor.