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Thursday, December 11, 2014

WPCT Shrink Sleeves

WPCT Wraparound Shrink Sleeves

     The original heat shrinkable sleeves designed to be used as corrosion prevention products on girth welds of pipelines were all manufactured as tubular products.  This mean the tubes had to be slipped into place before the pipe was welded up.  This also meant the tube had to slide far enough away from the welding area that the shrink sleeve wouldn't be damaged by weld splatter or excessive heat. 

     It was years until a wrap around shrink sleeve was developed.  What was the main problem?  How do you hold the sleeve in the 'shape' of a tube during the installation process and keep it in 'installed tube form' for the life of the pipeline?  The answer was to develop a closure strip which would do just that.

     Anyway, the WPCT wraparound shrink sleeve is an ancestor of those early, very first heat shrinkable wrap around sleeves.  There have been many improvements along the way.  WPCT right now stands for Wraparound Pipe Coating (with Thermal indicator).  (For a thorough explanation of what a thermal indicator is -- click).

     In its current form - WPCT is a product that is designed to be used on pipelines that will be buried or subea...AND will operate at or below 40C (~104F).  WPCT shrink sleeves can be manufactured for essentially any pipe size from 2.375" on up to 144" OD pipe or larger.  As a standard, WPCT is available in 11", 17", 24" and 34" widths and custom widths are available by request.

     Installation of the WPCT shrink sleeves is very simple.  After the weld is completed, the field joint area is cleaned with a power wire brush (or better).  The area that will be in contact with the WPCT sleeve (steel and adjacent pipeline coating) is then heated with a propane torch to at least 140F (often referred to as "hand hot").  The installer will then remove the release paper (exposing the aggressive, stick mastic) and wrap the WPCT shrink sleeve around the pipe snugly (no reason to leave a huge bag of slack in it).  This will result in the shrink sleeve overlapping onto itself.

     If you've purchased this WPCT material from us, you have a /UNI sleeve which means the closure strip has already been attached to one side of the sleeve.  This closure strip will go on the outside.  Heat that closure strip so that it bonds to the backing of the shrink sleeve forming a smooth tube.  Heat the closure with a propane torch so that the interior fabric reinforcement of the closure strip is able to begin showing (forming somewhat of a cross hatch pattern).  Once that is complete you are cleared to begin shrinking the sleeve (which ironically goes from a cross hatched pattern to a smooth surface). 

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