Question of the day - Tie-In at fitting

Thanks 11echo....as well the end preparation is more expensive at a fitting weld. You need to cut the weld seam, grind off the existing weld and then prepare it for the tie-in as you say.

11echo nailed it. The pipe basically has to be stress relieved due to the affected heat zone due to welding. This is safer to have that minmum pup length between fitings as described in 11echo's post. Also by cutting and grinding a fitting you could go out of round and out of accepted weld tolerance. A square cut can be made on a pipe and adjusted if need be. If done on a fitting you are restricted and the cut could compriomise the weld. Sometimes we try to minimise dead legs by welding close to a branch with a valve for a tie-in but you have created a small dead leg to the valve anyway so that small length does not make a difference.