COATED AND LINED PIPES


Aggressive and polluted environments (typical for refineries and downstream oil & gas) require the installation of coated pipes, i.e. pipes with external materials covering the bare metal.  In case the transported fluid is highly corrosive, pipe engineers have also to specify special internal lining for the pipes to install (internal lining is the application of special protective material inside the tubes). In this article, we illustrate the main types of coatings and lining materials used for steel pipes.


 

PIPE COATING MATERIALS

Coated pipes

In specific circumstances, coating materials are applied on the external surface of the pipe. The most common pipe coating materials are:

  • NON-METALLIC: Paints, varnishes, lacquers, bituminous coatings, resins, plasticizers, Greases, waxes, oils, Plastics (polyurethane, polyethylene, Rilsan, PTFE, PVC), Elastomers (various types), Vitreous enamel, Cement mortar
  • ORGANOMETALLIC: Paints pigmented with metals in powder form (aluminum, zinc, lead, stainless steel), Paints containing zinc ethyl-silicate
  • CHEMICAL MODIFICATION: Phosphating, Chromatin, phosphating, Black finishing and browning
  • PHYSIOCHEMICAL MODIFICATION: Cementation

 

Coated pipes

 

Video- FBE and 3 layer coating

Video – 3 Layer Polypropylene Coating (3LPP):


LINING MATERIALS FOR PIPES

Lined pipes are pipes that have an internal layer that protects the pipe material from corrosion. The lining is applied at the end of the production process of seamless and welded pipes. The most common materials used to line pipes internally are:

  • Cement mortar
  • Liquid epoxy
  • Glass
  • Fusion bonded epoxy (FBE)
  • Polyethylene
  • Bituminous asphalt
  • Zinc
  • Teflon (PTFE)

Lined pipes