Yard Pipe Coating

Hauling plant coated pipe over long distances, and the resulting frequent loading and unloading operations lead
to various kinds of damage to the pipe coating, some of them quite serious. Damage of this kind threatens
the viability of plant coating for pipe in view of the high cost of repair and loss of integrity of the anti–corrosion coating.

… Yet, it is not truly acceptable to shift focus to line travel coating, which can never equal the quality of plant coated pipe.

A solution to this problem lies in the use of mobile coating yards, which may be located close
to the pipeline right–of–way, at sites where other services have been established.

On the one hand, it is not usually financially sound to outfit coating yards with expensive extrusion equipment.
On the other hand, the quality of corrosion protection cannot be compromised.

Like a semi stationary plant, a yard is quickly assembled and disassembled, often in connection with a double
or triple jointing yard to enable more or less controlled environment coating to be applied to pipe along
the right–of–way. Yard coating of double or triple jointed pipe reduces the number of field joints to be subsequently protected.

In a yard environment most suitable are:

  • Hot Tape coatings
  • Liquid coatings
  • Cold Tape coating
  • Hot Enamel coatings

Liquid two–component coating systems

application of two–component
liquid coating

coating of girth weld

The application of two–component epoxy or polyurethane based coatings
is a good solution with semi–stationary coating yards.

Liquid two–component systems are used for the protection of:

  • steel structures (onshore and offshore) and their splash zones,
  • offshore platforms,
  • reservoirs,
  • onshore pipelines,
  • horizontal and directional drilling operations,
  • lay barge operations,
  • bends, fittings, valves, elbows, etc,
  • weld joints,

…and also for

  • pipeline rehabilitation.

The two–component coating systems are most often used for protection of small and medium–diameter pipe and for special applications.

Advanced pure and modified polyurethane and epoxy coatings, chemical and abrasion resistant, ensure complete corrosion protection for pipelines and steel structures.

The two–component polyurethane coating systems, Acothane
and Acothane TU (Metrotect), have both proven themselves well.

Ceramguard (Canusa) liquid polyurethane coating, with its exceptional plasticity and excellent abrasion and corrosion resistance, is used
for pipe protection in directional drilling operations.

airless spray unit for application
of two–component liquid coating

Moreover, coatings of this type are widely used in pipeline rehabilitation as a replacement coating or to repair damage
to existing coating.

damaged coating repair

Three–layer Hot Tape Coating

For pipe over 36" (914 mm) in diameter, three–layer hot tape coating is most often used.

Hot applied PE tape has been developed in order to allow application of three–layer coating in semi–stationary plant conditions without the use of expensive extruders. These ready–to–use tapes
are delivered in rolls.

The two main types of three-layer PE coating are Synergy and Vanguard (Polyken).

 

application of Synergy three–layer coating
in semi–stationary facility

Synergy — is a three–layer system consisting of

  • heat activated primer,
  • a layer of heat sensitive elastomer coating,
  • sturdy outer polyolefin layer.

When heated the layers fuse together, forming
a strong elastic coating, which cannot be penetrated by acids, moisture and other corrosive elements.

Synergy coatings have high shear strength, are highly resistant to cathodic disbondment, mechanically tough, compatible with cathodic protection, and have
a guaranteed service life of over 30 years.

Vanguard is a three–layer system consisting of a liquid two–component epoxy primer, adhesive and polyethylene in roll form.

Vanguard tape is wrapped on the pipe. The pipe
is then heated which cures the coating.

The layers thermally fuse and bond together during application, producing a complex thee–dimensional cross–linked network with rigid constraints in all directions.

The system provides excellent long–term protection against extreme weather, aggressive soil conditions, and environmental stress. The system also meets international standards.