Injection Molded Polyurethane (IMPU)

In order to provide a compatible field joint coating system for anti-corrosion coated pipelines (3LPP) and insulated pipelines (5LPP or more), PIH have developed and refined the process of using Injection Moulded Polyurethane (IMPU).

These compatible field joint coating systems provide anti-corrosion and (where necessary) thermal insulation properties, similar to the mainline factory coating whilst allowing routine application within the rapid production cycle times demanded by today's pipeline construction industry.

Now similar performance can consistently be achieved using state of the art solid or syntactic polymeric injection moulded coatings. These combine a low overall heat transfer coefficient (OHTC) with the ability to perform at elevated operating temperatures, whilst also providing excellent stand-alone anti-corrosion properties.

PIH have further engineered portable containerized elastomer-coating modules, to house all specialist purpose built polymer dispensing equipment. These containerised units can be easily transported to the job-site by conventional shipping methods, facilitating rapid set-up and deployment alongside the pipeline weld joints at site.

IMPU field joint systems are now available to offer total compatibility with the following factory applied coatings:

  • Standard thin-film (typically 1.5 to 4.5 mm thickness) 3-layer polypropylene or polyethylene external anti-corrosion coating barrier systems.
  • Multi-layer fusion bonded epoxy powder (FBE) / solid polyurethane elastomer systems (for operating temperatures typically up to 125°C).
  • Multi-layer solid or syntactic Polyurethane / Polypropylene systems, for pipelines where a very high OHTC (low 'K' factor) is necessary, in order to prevent problems occurring due to heat - loss from the pipeline.
  • 3 to 7 layer composite coatings incorporating an FBE base coat / co-polymer layer / a thick foamed polypropylene / plus a solid polypropylene sleeve (topcoat). These provide excellent anti-corrosion and thermal insulation properties, even at elevated operating temperatures.

Our IMPU system has proven ideally suited to onshore spoolbase operations as well as offshore, where the pipes are rapidly welded and field joint coated on-line prior to spooling the coated pipe strings onto the reel ship, for subsequent offshore pipe lay:

  • Highly compatible with thin film and multi-layer polypropylene or
  • polyethylene line pipe coatings
  • Incompressible polyurethane material suitable for deep water applications
  • Comparable thermal performance to factory applied insulation coating
  • Moderate pre-heat only to accelerate curing process
  • Suitable for operating temperatures up to 125°C
  • Suitable for field joints including J-Lay collars
  • Little diameter specific equipment required
  • Fast application and cure times