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Thursday, March 6, 2014

What is the Easiest Field Joint Coating to Install

What is the Easiest Field Joint Coating to Install

dirax field joint
Field joint coated with a DIRAX shrink sleeve system
     I had an interesting conversation this morning.  A contractor who doesn't historically get involved with steel natural gas pipeline installation has been awarded a contract to install a stainless steel natural gas pipeline.  At first glance, it sounds rather strange to be honest...but every company in every industry, at some point in time did something for the first time.  No one is born with experience.

     So this contractor, knowing that we are familiar with most all of the field joint coating technologies, wanted me to talk it through with him.  Here were some of his questions (and my answers):

Question:  Which field joint coating is going to be the least expensive for me to put on? 

Answer:  That depends.  First let me say that of the three primary field joint coating technologies (I'm ignoring field applied FBE here), each certainly has its strengths and weaknesses.  When considering a shrink sleeve system vs a two part epoxy vs a cold applied tape, there is a lot to consider and cost is certainly one of those factors.  Each of those three has areas where it excels and each has areas where it isn't as strong as the others.

So which coating is least expensive?  First, my brain will not allow me to ignore pertinent details.  It is impossible to jump right into "cost" without first considering SUITABILITY.  Making decisions based purely on material cost without considering other factors (application, pipeline conditions, time cost and labor cost as just a few examples) is a huge, huge mistake.  If there is a distributor, manufacturer or reseller out there who is advising otherwise; please let me know who it is because that would be irresponsible selling of the worst magnitude.

Based on that criteria listed above (since this line has road bore sections, is 12" heavy wall pipe and is in a very critical area), I am removing a cold applied tape system from the 'options' list right off the bat.  As I sad above, cold applied tapes certainly have areas of the pipeline coating world where they excel.  This is not one of them.

Since both shrink sleeves and two part epoxies were note eliminated based on that criteria, I can finally offer up an answer.  Are shrink sleeves or two part epoxies cheaper?  Yes.  I know, I'm drawing this out way too long.  Looking strictly at material cost, two part stand alone epoxies are generally going to be a little cheaper for road bore and directional drilling applications.  When considering a typical buried pipeline application without a road bore; shrink sleeves (like our WPCT product) are going to be the cheaper material strictly in terms of material cost.

Question:  My crews have no experience, which field joint coating is going to be easier to install?

Answer:  Well, to continue giving my honest opinion:  I believe a crew with absolutely no experience will be able to consistently, quickly and soundly install shrink sleeves sooner than they will be able to consistently, quickly and properly apply a two part epoxy stand alone product.  The quantities on this job would not justify purchasing spray equipment so the only option would be hand applied epoxy.

As I said about the tapes above; two part epoxies are great in certain situations.  In the hands of a brand new crew is not one of those situations.  I believe that shrink sleeves offer a relatively simple repeatability.  Epoxies on the other hand require a little more skill.  Getting a feel for gauging coating thickness; proper mixing technique to avoid introducing air into the epoxy; working the field joint to avoid icicles and inconsistent thicknesses, learning to efficiently use the epoxy to minimize waste, applying in a way that avoids any fish eyes from opening up -- none of those are particularly challenging in and of themselves.  Experienced crews avoid most of them most of the time.  But a green crew - with a likely very nervous inspector looking over their shoulder - is really inviting trouble if they think they will be able to master hand applying epoxy over the course of a two mile pipeline. 

So for me there is no question.  Go with the shrink sleeves, your life will be much easier and the pipeline will still be well protected.

Question: Ok, I'm convinced.  How do I know what width of a shrink sleeve I need to order?

Answer:  That one is easy.  A sleeve has to be at least wide enough to coat all bare steel and overlap onto the adjacent factory applied line coating by at least two inches per side.  Please keep in mind though, some end users require 3" per side or even 6" per side.  It is always better to be safe than sorry.  Check to make sure you're meeting the requirements of the specification before you buy anything!

And that was that, at least for this stage of the game.  Besides offering to include a free job kick off training session on site; there wasn't much else to do right now.  We will get the opportunity to train a brand new crew how to properly install our product (WPCT and DIRAX) and they will (hopefully) have a successful first foray into the world of steel gas pipeline construction.  

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