Lug type butterfly valve is often used when the valve is located at the edge of the piping system. This is because there is no other flange that will anchor the studs. The body of this valve type has lugs protruding on the sides of the body to provide a connection for the bolt holes. These bolt holes will then attach to their corresponding flanges. This design allows a certain side of the piping system to be dismantled without disrupting the other side.