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Monday, November 30, 2015

DIRAX Field joint Coatings

DIRAX Road Bore Coating

     Road bores and directional drilling applications put incredible stresses on pipeline coatings.  That is one reason that a main line abrasion resistant overcoat like Powercrete has been so popular over the years.  That is also one of the major reasons that dual layer FBE's and other ARO's have been developed, specified, sold and applied.  Product selection becomes a little bit more difficult when considering field joint coatings.  One of the main reasons this is the case is that field applications are dramatically different than coating plant (or lab) applications.  Crews aren't trained as well.  The environment isn't as controlled.  Nothing is stream lined in the field.  That is where the DIRAX product really shines.  Because of its simple installation, DIRAX installation is easy and consistent.  Two incredibly important features in a field applied coating.

     So, what are the steps of DIRAX installation in the field that make it so easily repeatable and consistent?  I'm glad you asked. 

  1. Surface preparation; while important; is not as critical as it is in a factory setting.  The anchor patterns required for many two part epoxies and fusion bond epoxy are not major factors with DIRAX.  Like any coating, of course the substrate needs to be clean (the cleaner the better) but anchor pattern are not a requirement.  Surface prep to SA 2 1/2 (and even wire brush in some cases) is all that is required.
  2. Epoxy thickness is fast and easy.  No more headaches trying to get a proper uniform epoxy thickness all the way around the pipe.  No more issues with an epoxy coating that is too thin on top and too thick on bottom with icicles and drips forming.  The DIRAX coating system utilizes our S1301M Epoxy as a bonding agent between the high shear adhesive of the DIRAX and the pipe surface (including factory applied coating).  The S1301M also acts as a coating enhancement; improving shear, peel, CD and other critical coating characteristics.  The S1301M is applied in a very thin layer; only microns thick and the coating integrity is not hinged upon a certain 30+ mil coating thickness in order to corrosion protect properly.  
  3. No real skill required.  There is no requirement for skill by the installer.  Their skill is not going to determine coating thickness.  Installer skill is not going to impact holidays or fish eyes or icicles.  The installers simply wrap the DIRAX sleeve around the still wet S1301M epoxy -- the DIRAX sleeve itself is designed to shrink 25%; so there isn't even any skill in wrapping the sleeve.  Wrap it snug?  That's fine.  Wrap it with a 1/2 inch bag?  Fine.  1 inch bag?  Also probably fine (depending on your pipe size).  After that you're simply shrinking the sleeve in a circumferential pattern starting on one end and moving toward the other.  
  4. Virtually no cure time.  No need wait multiple hours.  No risk of the crew pulling that pipe too soon (before the joint coating is cured) and ruining the coating.  No risk of someone bumping up against the pipe and creating holidays in the uncured epoxy.  The thinness of our epoxy, plus the heat of the steel preheat, plus the heat of the torch during the shrink process --- all leads to a fully cured coating system that is almost always ready to see stresses within just a few minutes after installation is concluded.  
  5. Minimal installation time is also a big factor here.  Ignoring surface prep (which will vary based on how dirty your pipeline is) - you are looking at just a few minutes per field joint of coating time.  This saves you labor costs.  Preheating the steel to 140F is very quick (will vary based on pipe size).  Mixing and applying the epoxy is only a minute or so.  Wrapping and shrinking the DIRAX sleeve and the Leader Strip is also very fast (I've installed sleeves on a 36" pipeline in only three minutes before).  

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