WPCT 10x18In the world of heat shrink sleeves, product nomenclatures can be confusing. At the same time, with more than one shrink sleeve manufacturer in the world, there is even more confusion added as everyone seems to try to use a nomenclature that might somehow make their product seem more appealing.
So in this article, I'll be talking really only about the different shrink sleeve widths available. Let's back up though I suppose at the beginning. What is WPCT?
WPCT is the Covalence (formerly Raychem) product designed for buried and subsea pipelines that will operate at ambient temperatures (104F and lower). WPCT itself stands for wraparound pipe coating w/ thermal indicator. Thermal indicator means that the backing of the sleeve is supplied with a dimpled cross hatch pattern and as the product is properly shrunk, the cross hatch pattern fades so that the backing becomes a smooth black surface. The sleeve has a built in tool to thermally indicate that it has received the proper amount of heat. Pretty neat huh?
Now the 10: The first number mentioned in a shrink sleeve inquiry is almost (note 'almost') always the outside diameter of the pipe. In this case that means this is your typical 10.75" OD pipeline.
So now we get to the '18'. Though shrink sleeve widths are completely customizable, there are standard widths that generally meet almost all requirements. Our standard widths are: 11.25", 17.75", 23.5" and 34.25". I know it seems strange (perhaps it makes a little bit more sense in metric, but that doesn't help us much here in the good ole USA. Go America!) Now what we do is we end up rounding those for simplicity sake (and to reduce the number of digits in the part number, thus saving hundreds of bits of data I guess).
What we call 11" is actually 11.25"
What we call 17" is actually 17.75"
What we call 24" is actually 23.5"
What we call 34" is actually 34.25"
Generally what we find is someone pulls out an old shrink sleeve that is left over from a past job and finds that it is 17.75" wide. They then round up --- and ask for an 18" wide sleeve. We then explain everything above (we call ours 17" even though they are 17.75") and it normally clears things up. I've certainly never seen a product rejected because it is 17.75" wide standard rather than the 18" mentioned on an RFQ!!