Testing 60"inch Flare Line 1

[Hansito]

Dear colleagues,

I've searched for "large diameter test" and couldn't find a similar situation to the following:

60 inch Flare line
Design code B31.3. Design pressure 10 barg, Design Temperature 300 C.
Strutures are designd for empty pipe.
The Client is affraid about pneumatic testing.

The procedure defined is:
Welding caps or plates, to each 6m or 12 m on the floor (or shop)remove the caps, field weld the piece on the pipe rack structure, made a 100% radiography. The same for mitre bends.

I always thought that the test (hydrostatic or pneumátic) should be done to all assembly not in pieces.

Please, can anybody confirm me that this strange procedure is valid or direct me to a previous similar post?

Regards,
Hansito

 

[Ballbearing1]

Hansito,
It does seem a bit strange because generally a hydrotest is performed to confirm the integrity of the welds.
Seamless and ERW pipe is randomly tested by hydrostatic, eddy current or ultrasonic testing in the mills where it is manufactured so it is considered acceptable without further testing.
Is it ERW pipe and is your client concerned with the integrity of the longitudinal weld ? That would be the only thing you were testing if you capped off 6 metre lengths.
It would probably be quicker and more cost effective to RT (or UT )100% of the longitudinal weld (if that is the clients concern)than weld caps on every 6 metre length and then hydrotest each one.
Regards,
BB

 

[racookpe1978]

Your question starts (is titled by) "flare lines" ...

would these type of lines actually be ever "hydro-tested" if they are open-ended - as flare lines actually are.

 

[arto]

Could you just stand it up when complete, seal the bottom & fill with water? that would give you ~880x the pressure from the column of air. just made sure it can take the "Full of Water" weight

 

[stanweld]

Recommend asking the Owner for permission to use either the Sensitive Leak Test defined in 345.8 od B31.3 or the Alternative Leak Test defined in 345.9 for the flare line.

 

[Hansito]

Thanks for all you valuable answers:

Balllbearing: our client insists in keep (hydrotastic test)on the line list, however he approved the structure designed for empty pipe. I say that is dangerous to keep this indication on line list can promote a desaster on site, because anyone (like me who is entering on this project) will think the line is designed for that.

Racookp1978. Yes it is a flare line. Do you mean that an opened line never requires Hydrostatic. In that case I see no sense in defining a design pressure.

Arto: No, it is to late, the structure and the span adopted do not allow for fill it with water.

Stanweld: Thanks for your advise. I do want to talk with client, my problem is, since I'm new on the project and other representats from my company had done this previously (not very well documented) I have to be careful to do not provide more confusion.

Please, if any of you or someoneelse have something more to add, do it. I do appreciate your ideas and comments.

Regards,
Hansito

 

[Ballbearing1]

Hansito,
I have dug a bit further and unfotunately you are not in a good position if your client refuses to budge.
However, your clients engineering department should have reviewed and approved the design of the structures so they can hardly say you cannot hydrotest due to weight at this late stage.
1 Design temperature is over 186 degrees C so you must hydrotest as per ASME B31.3.(even if it is open ended)
2 You cannot use the Alternative Leak Test (345.9) unless you comply with both 345.1(1) and (2)and in this instance you do not.
3 The Sensive Leak Test (345.8) is part of the requirements of 345.9 (345.9.3) so that cannot be used either.

The only thing I can find that may be of relevance is 345.3.2 Temporary Supports "Piping designed for vapor or gas shall be provided with additional temporary supports, if necessary, to support the weight of the test liquid."

Strengthen your supports, weld all the pipe in the rack, perform 5% radiography and then a final hydrotest. Voila !

Not sure if that helps but good luck,
BB

 

[racookpe1978]

Find out the cost and schedule impact of those "temporary supports" for the entire pipe rack and falre tower

Plus the cost of welding-on and isolating the test cover plates (remember, those will be up high on scaffolding at the end of the "open-ended" pipe - add that delay as well)

plus the cost and schedule impact of removing the supports

plus the cost of the hydro itself (people test rigs, times, etc.)

Then make sure he is willing to acept that price to test a permanently open-ended pipe. Make sure is charged for that extra cost. Make sure your boss - and up your chain of command knows all the costs. Ratchet up the pressure on the bosses BEFORE you add pressure to the pipes.

Yes, it is designed for 10 bar. What is its actual max pressure under operation?

 

[Ballbearing1]

racookpe1978,
It appears that money is no object to this client. The original post was that the client wanted to weld end caps on every 6 or 12 metre length, hydrotest, cut off the caps, reprep pipe, install in rack, weld out and then 100% RT.
Whether they go with the clients scenario or the one I have suggested it is going to be a hugely expensive project. One that should have been sorted out in the design stage of the project.
10 bar (1000 kpa) makes the pipe eligible for Cat D (ISLT) but the design temp puts it into NFS so hydro is required as per the code,
Regards,
BB

 

[rodofgod]

Hi All!

"1 Design temperature is over 186 degrees C so you must hydrotest as per ASME B31.3.(even if it is open ended)"

Can someone tell me where it states this in B31.3?

Regards

 

[Ballbearing1]

Rodofgod,
All piping fabricated in accordance with B31.3 must be subjected to a pressure test, be it hydrostatic or pneumatic or a combination of both. There are certain exemptions and one of these is an Initial Service Leak Test as per Cat D but this is only applicable if the design temperature is less than 186 degrees C, design pressure is less than 1035 kpa and the liquid / gas is not harmful to human tissue.
Hope that clarifies,
Cheers,
BB

 

[rodofgod]

BB,

Most helpful, as always!

Thank You!
Think I will stir some people up tomorrow!

Regards

 

[Ballbearing1]

Rodofgod,
Open ended drains / vents etc are always a contentious issue. However the code does not recognise that the piping is open ended, only that it has a fluid / gas that is classified on its pressure, temperature and hazard grading.
Knowing the "loopholes" in the codes can be hugely beneficial at times.
On my last project I was able to get a Concession Request accepted to reclassify 18,000 piping systems to Cat D and therefore no hydrotest required.
Got a good pat on the back for that one.
Regards,
BB