WPCT was originally developed in the early 1970's as a wrap around, heat shrinkable plastic sleeve for coating girth welds on pipelines.In its earliest form, WPCT did not possess as thermal indicator and was called WPC.In the 80's the heat shrink backing of the sleeve was coated with a green thermochromic paint that could act as a thermal indictor for installers and the product nomenclature was changed to WPCT.

WPCT remained mainly unchanged for a decade at which time a new thermal indicator (PCI) was developed.WPCT has been the most commonly used heat shrink sleeve in the world.

Uses of WPCT

WPCT is Raychem's wrap around shrink sleeve designed for ambient temperature buried or subsea lines.WPCT utilizes a mastic sealant to protect the bare steel from corrosion.

WPCT can be used for coating girth welds on pipelines or for coating long lines or pipe; depending on the application.

Sizing of WPCT

Raychem nomenclature is very simple.The first series of letters/numbers is the material type (WPCT); the second set of numbers is the pipe diameter in mils, the third number is the width of the sleeve in inches and the final /UNI signifies that the closure has been pre attached during production.Examples:

WPCT 3500-11/UNI (for a 3.5" OD pipe; 11" wide)

WPCT 6625-17/UNI (for a 6.625" OD pipe; 17" wide)

WPCT 24000-34/UNI (for a 24" OD pipe; 34" wide)

WPCT can be made for any pipe diameter from 2.375" on up to 144".

Installing WPCT

When installing a coating; the cleanliness of the substrate is one of the single most important things.WPCT is no different; but because it is coated with a very aggressive mastic, it is more forgiving than most coatings.WPCT requires a surface to be wire brushed clean and free from any loose materials such as dirt or oil.

The next step is to preheat the pipeline to a minimum of 140F.Heating the steel and adjacent line coating help the WPCT to properly bond to the substrate.Beyond cleaning, this is the most important step when installing WPCT.

Then the WPCT is wrapped around the pipe, in the location where it will be installed.The Closure strip is heated and patted down to the WPCT sleeve and will serve to hold the sleeve in the shape of a tube during the installation process.

Next the overlap area of the WPCT is rolled; and a visual inspection to be sure the WPCT sleeve fully conforms to the pipe surface and that there is mastic flow evident at both sides of the sleeve.