The use of insert flanges, made specifically to make jacketed piping assembly easier, also avoids the cost of alternate jacket closure methods such as closure rings, swaging the ends of the jacket pipe and custom machining the backs of standard B16.5 flanges. Instead the inserts are machined to offer easy and proven attachment methods to the process pipe and jacket pipe via slip-on type fillet welds, butt welds, or full penetration corner joints.