WPCT Standard Shrink Sleeves
WPCT was one of Raychem Corps great advances in the world of heat shrink sleeves that dates back quite a few years. Many times over the years, WPCT heat shrink sleeves have been the absolute work horse of the Raychem product line. A very field friendly shrink sleeve; utilizing a butyl mastic sealant; there are literally millions of WPCT shrink sleeves currently in use on underground piping across the world. Looking only at my little slice of that business; I can say with certainty that we have sold more than one million WPCT shrink sleeves in recent years.
In my twenty one years of experience selling WPCT wrap around sleeves; how many "failures" have I heard of? None. How is that possible? The product type and lot numbers are printed on every sleeve. As we all know; detailed records are kept of pipeline coating solutions that are installed on pipelines across the USA and across the world. When a corrosion problem occurs; it is quite easy to determine what is going on. Especially when pipe is dug up and evaluated; it is very easy to determine what has gone wrong with a visual inspection. And in my decades of experience, I've not had a single call. Why is that?
I believe it is because the thermal indicator built into the WPCT shrink sleeve backing:
Here you can see what I mean by the thermal indicator. This is a picture of a partially installed WPCT shrink sleeve. On the left; we see the backing as supplied. The cross hatch pattern is imprinted in the backing of the sleeve after the sleeve backing has been expanded (which happens after crosslinking). On the right side, we see what the sleeve backing looks like after proper installation: a smooth PE backing. This is a permanent change (I made this sample several years ago). This means that the installers have a visible cue during the shrink process to see that they are properly shrinking the sleeve. This also means that foreman can see that the sleeve is properly installed during and after the install process.
For inspectors; this is a fantastic tool. Sleeves can be inspected minutes, hour, days, weeks or months (or years) after the installation. If there is a pattern on any section of the sleeve --- that sleeve needs more heat! Simple.
In addition to this tool; there are others of course. Mastic flow should be evident at all edges of the sleeve. The sleeve surface should be fully conformed to the pipe. The step down from adjacent factory applied coatings and weld bead profile should be evident.
WPCT is a fantastic product - easy to install - inexpensive - reliable. Hundreds of thousands of currently active pipelines prove that to be the case.
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