Lap Joint flanges are used on piping fitted with with lapped pipe or with lap joint stub ends. The lap joint flange with the stub end assembly are normally used in systems requiring frequent dismantling for inspection and cleaning and where the ability to swivel flanges and to align bolt holes materially eases the erection of large diameter or unusually stiff piping. These flanges are also used in applications where there is a need to facilitate bolt alignment. These type of flanges are similar to slip-on flanges. The only difference is that it has a curved radius at the bore and face to accommodate a lap joint stub end. They may be used at all pressures and are available in a full size range. These lap joint flanges slip over the pipe, and are not welded. They are otherwise fastened to it. Here the bolting pressure is transferred to the gasket by the pressure of the flange against the back of the pipe lap.