Purethane® has excellent corrosion protection properties as well as outstanding mechanical toughness in a single monolithic coating. Field joints, a weak point in other coating systems, are a continuation of the pipe coating with no discernable discontinuity between the morphology of the pipe coating and the joint coating.

Buried pipeline external coatings like Fusion Bond Epoxy (FBE) are brittle which makes them prone to handling damage. 3 Layer Polyethylene / Polypropylene coating consist of multiple layers serving different individual functions – corrosion protection FBE primer / co-polymer adhesive / mechanical protection PE/PP topcoat. However the inherent low level of chemical bonding between the layers makes them prone to disbondment on soil stresses. Old generation coatings like Coal Tar Enamel provide low level of corrosion protection and are mechanically weak. They have a tendency for chemical breakdown due to alkaline environment generated by cathodic protection currents and are hazardous to apply.

Desired properties of an external coating for buried service, identified by NACE International RP 0169-94 are listed below :

  • High Electrical Resistance

  • Low Permeability

  • Mechanical Properties to withstand damage during transport, handling , laying, bending , testing and back filling :
         High Adhesion
         High Impact Resistance
         Flexibility & Elongation

  • Resistance to Cathodic Disbondment

  • Physical stability and chemical resistance to prevent deterioration during design life
         Cohesive Strength To Prevent Cracking
         Resistance To Cold Flow & Thermal Stresses
         Resistance To Soil Stresses

Technical Bulletin elaborating the implications of these properties and comparing test results of Purethane® 386/9000 with other external coatings now available. Ask for a copy (Acrobat File) by E-Mail !

Minimum standard for 100% Solids Polyurethane Coatings are prescribed in American Water Works Association / American National Standard Institute “ANSI / AWWA  C-222-99 Polyurethane Coating For The Interior & Exterior Of Steel Water Pipe Fittings” as well as DIN 30671 Thermoset Plastic Coatings For Buried Steel Pipes. Purethane® 386/9000 greatly exceeds all the requirements.

Purethane® has the unique capability of being applied either in the yard or at the site. Setting up temporary mobile coating yards at the installation site(s) leads to large savings in transportation of pipes to remote coating yards and back.

"In the ditch" application capability also makes Purethane®ideal for re-habilitation of existing lines with deteriorated coatings. NACE International, USA endorses 100% Solids Polyurethane for Pipeline Re-habilitation Under Technical Committee Report, Task Group T-10D-17/T-6A-63, dated July 1999 “Coatings for Repair and Rehabilitation of the External Coatings of Buried Steel Pipelines”. Being a “Hybrid” polyurethane Purethane® has alkali resistance of the highest order.

Purethane® is impervious to Sea Water, H2S, Sulfates etc. making them ideal for offshore applications as well as for internal lining of pipelines in corrosive service. Outstanding impact and abrasion resistance makes them the coating of choice for Slurry Lines and Horizontal Directional Drilling applications. They are totally inert, non-toxic and odorless allowing use in drinking water lines. Pipeline applications of Purethane® include:

 
  Internal Lining   External Coating
  • Oil & Gas Pipelines Such As Sour Crude, Sour Gas with CO2, H2S etc.
  • Sewage And Wastewater
  • Pre-stressed Cement Concrete  Pipe (PCCP)
  • Drinking Water
  • Slurry Pipe
  • Cooling Water ( Raw , Sea )
  • New Oil & Gas, Drinking Water & Waste Water   Pipelines
  • On Site Re-Habilitation Of Pipelines With Deteriorated Coating.
  • Offshore Pipelines, Outfalls
  • Horizontal Directional Drilling 
  • Pre-stressed Cement Concrete  Pipe (PCCP)

Click on the links to see newsletters for applications of Purethane® 386/9000 on  Buried Oil & Gas Pipeline as Internal Lining of Seawater Pipe and external coating of pipe installed using Horizontal Directional Drilling technique.