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Friday, October 4, 2013

How Do I Remove a Heat Shrink Sleeve?

How Do I Remove a Heat Shrink Sleeve?

     It is important to keep in mind that heat shrink sleeves (at least Covalence shrink sleeves (formerly Raychem)) are not designed to be removed!  These are products that are designed to stay in place; well bonded to your pipeline; unaffected by soil stress and pipe movements; for the life of your pipeline (25+ years).  These are intended to be essentially permanent.  

     So, when you need to remove one; you've got a problem on your hands (which speaks to the effectiveness of the product).  When I get this question; I always answer it with a question.  Why do you need to remove a shrink sleeve?  The answers I've gotten to that question could probably make their own blog post; so I'll ignore it for now.  Let's pretend that you have valid reasons for attempting to remove a shrink sleeve (in other words; repairing, encapsulating or installing another shrink sleeve on top of this one are not being considered). 

      There will be some variation in removal protocol depending on which specific shrink sleeve type you are trying to remove.  Removing a shrink sleeve just isn't as simple as grit blasting, like you would with an FBE or an epoxy (which can be removed pretty easily).  In the case of a shrink sleeve; you're going to have to first consider how to remove the heat shrinkable polyethylene backing (which has been radiation crosslinked) and then consider how to remove the sealant that is still on your pipe!

     The problem is, in order to get the shrink sleeve removed; you're going to need to do a LOT of heating and a lot of scraping to that area of the pipe.  It is possible that you'll will end up damaging some of your adjacent factory applied line coating in the process.  IF you are able to get enough heat into the sleeve to get the outer heat shrink jacket removed; you will then have to to get even more heat into the mastic / hot melt adhesive in order to scrape as much of that off as possible.  No matter how well you do that job; you will almost certainly still be left with some amount still on the pipe.  This sealant will then likely resist the grit blasting to some degree (because it is a softer material).

     All of that to say; your life will be much easier if you explore all of the other options first (repair, etc).  Removing a shrink sleeve isn't easy.  It isn't supposed to be easy.  If removing shrink sleeves was an easy proposition; they would not be considered great pipeline coatings.  If removing shrink sleeves were easy; that would have been evident in the big GTI pipeline coatings evaluation that was conducted a few years back. 

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