Flanged connections with dissimilar Materials

For a spec break with change in material near a flanged joint (may be equipment flange and piping flange) what should be the correct approach:

1. Have spec break at flange-pipe joint (with dissimilar welding at the flange-pipe joint) and avoid leakage because of unequal thermal expansion.
2. Have spec break at the gasket (face of flange) and avoid dissimilar material welding.

May be temperature and type of materials will play a key role. When can we go with option # 2 safely ? Received on Wed Jul 03 08:25:00 2002