Re: Ho t Taps

No flow for hot tap. Yes provided that an assurance can be made in writng that theres no poosibility of a flammable mixture going to exisunder the no flow condition.

The API 2201 says 5 mm. The problem arises with SS mat'l since typrically the wall thickness is under 5 mm. TDW in their website says its doable. It is provided that a detail analysis can be shown that the piping is not compromised.

The reason for the reduce flow is very nice question. A lot says to cool the affected areas around the weld zone. Wrong. Its to assure that thre's no formation of flamable mizture while you do the hot work. Cooling in fact is bad during leading - we preheat, but ive never heard of precooling.

Question now is, is it ok to perform a hot tap above 120F without waibing any reqt of the API?

• In PipingDesign@yahoogroups.com, "SARE, RALPH H." <SARERH@Y...> wrote:
  > you're welcome.
  >
  > i was hoping there will be a followup question like - is it
  permissible to
  > hap tap under a "no-flow" condition. Or what is the min. thickness
  of pipe
  > to prevent weld metal blowout; why is it necessary to reduce the
  pressure
  > and maintained the flow, how does one figure out the max. allw
  operating
  > pressure, any precaution to be obeserved before striking the arc,
  how do you
  > peform the hydro if the surface metakl etc.
  >
  > > ----------
  > > From: Rendolf Michel Tatuhey[SMTP:r.tatuhey@p...]
  > > Subject: RE: [PipingDesign] Ho t Taps
  > >
  > > Thank you Sare.
  > >
  > > -----Original Message-----
  > >
  > >
  > > .
  > >
  > >
  > >