Repairing Polypropylene Pipe Coatings

Polypropylene Pipe Coating Repairs

     Three layer polypropylene pipe coatings are becoming more and more common in the world of oil and gas pipelines.  While polypropylene (PP) does have a number of advantages:  excellent abrasion resistance, high temperature suitability, etc...PP also has at least one fairly significant disadvantage:  it is difficult to bond to.  This can very often cause problems when selecting field joint coatings or when determining the best way to repair damage to the line.

     With polypropylene pipe coating repair, we essentially have three different options:

1:  PP Melt Stick:  This is a stick of polypropylene adhesive which is melted and dripped/manually manipulated in order to fill cracks and pinhole type damage. 

2:  PPRP:  Polypropylene Repair Patch used in conjunction with filler epoxy in order to rebuild damaged areas and place a seal on the outside of the PP coating, encapsulating all damage to prevent any ingress of water or oxygen.

3:  WPC100M Shrink Sleeve:  this would involve packing any significant damage with a high temperature mastic material in order to rebuild the thickness of the coating to be a uniform thickness.  Then a WPC100M shrink sleeve would be installed around all of it, encapsulating the damaged area to prevent water ingress.  The limitation of this method:  WPC100M is rated to only 100C when installed offshore.  If the line will operate at a higher temperature than that, another option would need to be considered.  If the insulative properties of the PP coating will create an environment in which the WPC100M will not be exposed to temperatures above 100C, then the WPC100M can be used no matter the operating temperature of the pipeline.