WE ARE FABRICATING A 16" DIA. LINE TO ANSI B-31.3.SLIP-ON FLANGES ARE BEING USED.STRESS RELIEV IS REQUIRED AS A SERVICE REQUIREMENT.DO WE HAVE TO STRESS RELIEV THE SLIP-ON FLANGE'S WELDS,IS IT OK TO DO SO,ANY EFFECT ON THE EXPANSION DURING S.R AS THEY ARE WELDED FROM INSIDE AND OUTSIDE