Leakage form Main gas Transmission Line- Repair Strategy

[mechcolor]

Just go ahead with operating this piping under safe pressure.

Hey Mechcolor,
Was away on vacations. Yes i've performed MAWP calculations.
The difference b/w MAWP & operating pressure is nearly 200psig. MAWP being on higher side.
Any advice?
Regards
NAQ

[ben]

1. You must obtain a copy of Qualification test from the vendor which must contain third party approvals in performing composite repairs.
2. Composite repair can be used as a permanent repair but I suggest you must replace the thinned area of piping with a new one in next plant shutdown. Reason behind this is the continual applicable inspection checks would be easy for you to perform on metallic piping instead of composite.

Ben, Have explored a local agency who performs composite repairs. They have provided following procedure.
1)- Surface preparation & have 3 options a)- Sand/grit blasting (not possible in our case due to low thickness & hig pressure natural gas inside) b)- Power brush cleaning c)- cleaning thru emery paper.
2)- Application of polymeric base to fill deeply pitted areas & to make the surface smooth.
3)- Wrapping of the build up /effected area with a multi directional woven glass fiber cloth after rinsing it in the Epoxy based resin.
4)- Curing of the wrapped glass fiber cloth for some specified time.
Would like to seek your advice that how we can make sure that the repair they are going to perform would sustain the pressure running inside pipe (if the pipe leaks after few days/weeks etc.
Also are these composite repairs to be considered Temporary or Permanent?
Regards
NAQ

[Nabeel Ahmed Qureshi]

We have evaluated an other repair option for subject issue which is ESR - Epoxy Sleeve Repair.
Epoxy grout covered with Metallic sleeve(bolted). Can any one share his comments / experience/References about this ESR?

[irish]

ESR is the proven technique for repairing the defected areas of piping having non leaking defects. Like in your case, the recent developments have been proven successfully to repair the corrosive portions of the piping with this technique. Implications of metal loss can be overcome by using ESR as sometimes the repaired portion is more healthy than even the sound portion of the piping.
Google ESR and you would be finding much literature on this.

[Nabeel Ahmed Qureshi]

Thanx Irish.
Did you have any experience with ESR? What are the quality checks to be employed to gauge repair effectiveness?

[irish]

I have not experienced ESR though it was done some 3 years ago at my earlier working place.
Most of the quality checks can only be made by the qualified staff involved in undertaking ESR.
Hope they would be submitting you all the required documentation prior to starting the job.