Re: Hot Tapping a PWHT Amine Gas Line

dont you believe it. Hot tapping is definite no no if piping require a PWHT. The reason is obvious. Your working on live line. Its just one big heat sink meaning you will have a very little chance of raising the temp. The other problem is that if any of this amine gas leak between the pads and the pipe then you may have a problem.

There may be a way. Dont perfomed a PWHT? But is a amine service and its required - sure. Consult with your metallurgist and see if you can substitute a temper bead welding and increase your preheat temp.

• In PipingDesign@y..., "regoldst" <regoldst@a...> wrote:
  > I've been told a hot tap on a PWHT Amine Gas (vapor) Line could be
  > accomplished and meet the stress relieving requirements with the
  > right welding procedures. This line is 12" sch 40 A106,GR B line
  with
  > an 8" Hot Tap connection required. We can't take a shutdown and we
  > can't find a spare valve or section to isolate and stay on line.
  >
  > I need to know if anyone has had any experience with this
  situation.
  > All I need to know is can it be done?
  >
  > The Line is in an interconnecting pipe in a major Oil Rfinery
  built
  > to B31 Codes in the United States.
  >
  > Thanks