hydrotesting for threaded pipes 4

[crueltobekind]

does threaded piping need to be hydrotested?

ive been told that hydrotesting is only required when there are welds involved. however, i think it should still be required for threaded connections. im not sure if these connections will be seal welded. i think thats left up to the pipefitters .

Pipe is 3/4"
design pressure: 4000 kpa

 

[pennpiper]

Question - Does threaded piping need to be hydro-tested?
Answer - It depends on the commodity and the specific standards (or wishes) of the Client.

Statement - I've been told that hydrotesting is only required when there are welds involved. however, I think it should still be required for threaded connections.
Comment - It depends on the commodity and the specific standards (or wishes) of the Client.

Statement - I'm not sure if these connections will be seal welded. I think that's left up to the pipe fitters.
Comment - NO! it is not left up to the Pipe Fitter. The requirement for Seal Welding (or not) is up to the Piping Material Engineer's Line Class Specification for that commodity for that project.


prognosis: Lead or Lag

 

[LittleInch]

As pennpiper says it depends what your code says, but I can't see why threaded versus welded makes any difference. What you're testing in a pressure test is the strength of the joint and the material and fittings. Screwed joints can fail if someone cross threaded or used the wrong size or thread and lots of PTFE and pipe and fittings sometimes fail too. Atmospheric pressure drain piping maybe not, but anything else holding pressure, yes

Never quite understood seal welding, if you can weld a threaded joint, which you then can't undo, why not just weld the thing in the first place??

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[MJCronin]

I agree with Pennpiper..... and gave him a star...

I guess what bothers me the most, are the "whatdoyathink" questions from newbie people who are certainly designing piping systems.

These "first-timers" seem astonished that piping codes even exist.....much less rules that must be understood by engineers.

Why cant anyone who can draw roads, garages, landscaping and housing developments, design high pressure steam systems ?

Why cant you just get some pipefitters together and ask them all of the questions ? Let them decide on the pipe materials, coatings and wall thicknesses.

Oh...... and let them route pipe without drawings, install whatever kind of pipe supports that strikes thier fancy....

If there are any questions, you can always ask a stranger on a engineering forum.

 

[racookpe1978]

4000 kpa??????? 580 psi.

Surprised the project is using threaded pipe.

What fluid, what temperature will this be running at?

 

[LittleInch]

I didn't look close enough at that. Definitely needs hydrotest at that pressure.

MJ Cronin, I'm with you on that front. I am becoming surprised at the sorts of questions appearing here from people who are clearly designing systems with potential to kill or seriously injure people with seemingly low levels of knowledge about piping design.

I have no problem with the pressure, drill piping is screwed at ,000s of psi, but not testing it is an issue.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Gator]

LittleInch, it's called "value engineering". Which is somewhat ironic, since often the proponents of the trend don't seem to actually value engineering much.

Paul

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