Lap Joint Flanges (LJ Flanges) are used on piping fitted with lapped pipe or with lap joint stub ends the combined initial cost of the two items being approximately one-third higher than that of comparable welding neck flanges. Their pressure-holding ability is little, if any, better than that of slip-on flanges and the fatigue life of the assembly is only one-tenth that of welding neck flanges. 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. Their use at points where severe bending stress occurs should be avoided.

Lap Joint Flange Description