steam supply (seamless or welded pipe)
steam supply (seamless or welded pipe)
(OP)
I know that the schedule and the fluid are important to determinate the kind of piping for an new installation.
For steam supply in a common power plant 150# or 300#, what is it as the suggested pipe to install?, of course without considerer economical reason. (the seamless pipe is more expensive than welded)
Thanks advance
For steam supply in a common power plant 150# or 300#, what is it as the suggested pipe to install?, of course without considerer economical reason. (the seamless pipe is more expensive than welded)
Thanks advance





RE: steam supply (seamless or welded pipe)
But I also understand that people usually have a more peaceful mind when they know that the pipe is seamless instead of welded.
Regarding the economics, when the wall is very heavy, the welded pipe is not that cheaper than seamless any more.
I am not in power plant business, but specific concern or quetions can help others to respond.
RE: steam supply (seamless or welded pipe)
RE: steam supply (seamless or welded pipe)
Welded tubing within the boiler enclosure is permitted by code, but some customers will not allow it for issues related to reliability. One US boiler mfr had used welded carbon steel tubes in HRSG's built about 7 yrs ago, but because the foundry's UT machine was not performing properly , a lot of tubes failed which led to a massive set of lawsuits related to the lost unit availabilty and cost to replace all CS welded tubing.
RE: steam supply (seamless or welded pipe)
htt
by the way, I thought this was a well written article...
Joe Lambert
http://www.control-associates.com/
RE: steam supply (seamless or welded pipe)
RE: steam supply (seamless or welded pipe)
RE: steam supply (seamless or welded pipe)
Exactly as Metengr says. Look into the weld strength reduction factor and pay attention to B31.1, Paragraph 102.4.3 and Table 102.4.3 regarding longitudinal joint weld efficiency factors. For some P/T services the seam welded pipe might require additional wall thickness or additional NDE of the seam weld.
John
RE: steam supply (seamless or welded pipe)
RE: steam supply (seamless or welded pipe)
In terms of ease of fabrication and quality, your mileage may vary depending on whose pipe you buy, what material and what size. I've seen lots of seamless pipe and tubing which was pretty horrible on the ID, whereas someone else here claimed that the ovality can be bad on welded pipe yet I've never personally seen the latter.
We've not seen an example in our shop yet, but have heard plenty of rumours on this forum and elsewhere that A53 welded pipe, particularly from China, sometimes has a seam of questionable virtue regardless what the mill certs say. Considering how cheap A106 seamless is at small sizes, it's one of the few occasions where I'd say that seamless is worth the premium even when not hard spec'd by a client or a Code.
RE: steam supply (seamless or welded pipe)
Where? Appendix A mentions limitations for use for BEP (boiler external piping) only, and as I said because of Section I. For BOP, you can use seamless.
RE: steam supply (seamless or welded pipe)
RE: steam supply (seamless or welded pipe)