Re-using 20 year piping in a chemical plant

[QCJT]

Hello All,

My Client wants to replace some of the old equipment in the plant and the question is weather to replace or not the piping which is connected to this equipment, which is also of the same age (20 years). At this moment I dont have any maintenance inpsection reports and do not have any idea about remaining wall thickness of the piping or their condition but I want to hear from you the general approach to these kind of issues. There are pros and cons in both scenarios:
Replacing pros: 1) We will cut the pipes out in any case for enabling the removal and replacement of equipment. The removed piping maybe discarded and replaced with new ones, without loosing much time as most can be prefabricated
2) With new piping we can have sufficient overlength to avoid shortages
Replacing cons: 1) We are not replacing all of the piping in the plant, the cut out sections that are to be replaced aren't necessarily the worst (most corroded) part of the pipingı 2) introducing new, thicker wall pipes may cause some issues during fit up.
Reusing pros: 1) much less work and costs (even insulation could be reused on certain parts); 2) same wall thickness as the remaining pipe
Reusing cons: 1) unknown condition of the steel (grain size due to pwht, corrosion and etc); 2) potential shortages of material due to cutting, grinding etc.

Note: if reusing, we plan to make cuts on the center of the weld, prepeare the bevel and lpt for cracks and only then weld. If we need to remove by grinding more steel than the weld metal, we will compensate by buttering in addition an extra length of new pipe will be available just in case we need to replace a section.

Piping is mostly carbon steel (among them also P22), some 15NiCuMoNb5 steel and some A182, 304H.

What would be your primary concerns in case of reusing and which option would you be inclined for? Looking forward to all critical and informative comments.

 

[bimr]

You will be adding some risk to the project schedule and some uncertainty to the project cost. Plus a liability and warranty issues since the client will expect you to be responsible for repairing the old piping should it fail.

The installation labor is likely to be more expensive than the piping, so it does not make any sense to reuse the piping.

 

[Latexman]

It only costs a little extra to use used equipment!

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[Gator]

What service and why would you use thicker wall pipe if you're going with new piping. bimr makes a good point about warranty.

Piping Design Central

 

[QCJT]

Thanks so far for all the input. Gator, i am saying thicker wall because it is expected that in 20 years there would be some wall reduction on existing pipes and new pipe will be then thicker. This is risers and downcomers to the steam drum and connecting piping to the transfer line exchangers (boiler (feed) water, cooling water, purge steam, exhaust steam, cracked gas, xs blowdown, condensate)

 

[MikeHalloran]

The binders that hold insulation together, and even allow its fabrication, often do not survive the first real heating cycle, so many insulation types just sort of crumble to dust when you try to remove them. I would not assume that any insulation is reusable or recoverable in any way.

Twenty years in steam service is a long time, maybe two thirds of a plant's life expectancy.
Without regard to any disclaimers you may issue, when the reclaimed pipe fails in ten years or so, your phone will ring.

I wouldn't re-use a damn thing except exactly what the client demands, >in writing<.


Mike Halloran
Pembroke Pines, FL, USA

 

[Gator]

"it is expected that in 20 years there would be some wall reduction on existing pipes and new pipe will be then thicker"

What I meant was: If you're going to install new piping, why would you specify 'thicker' (heavier wall) than what was installed in the facility 20 years ago?

Piping Design Central