Injection Molded Polyurethane (IMPU)

In order to provide an alternative yet compatible field joint coating system for 3LPP anti-corrosion coated pipelines and a versatile solution for Multi-layer PP and Syntactic PU insulated pipelines PIH have developed and refined the process of using Injection Moulded Polyurethane (IMPU).

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

Similar performance to that of the parent coating can consistently be achieved using state of the art solid or syntactic polyurethane 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 IMPU coating modules to house all specialist purpose built 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 welded 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 systems.
  • Multi-layer fusion bonded epoxy powder (FBE) / solid polyurethane elastomer systems (for operating temperatures typically up to 125°C).
  • Solid or Syntactic Polyurethane / systems, for pipelines where a very low OHTC (low 'K' factor) is necessary.
  • Multi-layer composite coatings incorporating an FBE base coat / co-polymer layer / a thick foamed polypropylene / plus a solid polypropylene sleeve (topcoat).

In addition to offshore laybarge production, our IMPU system has been proven to be ideally suited to onshore spoolbase operations, 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.

The benefits offered by the IMPU Field Joint Coating are:

  • 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