1. The cut-back areas of Coated Pipes where weld joints are made are to be Coated by Field Joint Coating.
2. Field joint coating material is heat shrinkable wraparound sleeve used as anticorrosion coating of buried onshore pipeline.
3. Sleeve consist of radiation cross-linked, thermally stabilized, ultraviolet resistant semi-rigid polyolefin backing with a uniform thickness of high shear strength thermoplastic/co-melt adhesive .
4. The joint coating system shall consist of a solvent free epoxy primer applied to the pipe surface prior to sleeve application.
5. The surface area is blast cleaned to SA-2.5 followed by Pre-heating of pipe surface, application of epoxy primer and application of sleeve by heat shrinking.
6. Each sleeve joint is inspected by means of a full circle holiday detector set to DC voltage at 25 KV (Pipe surface temperature below 50 degree Celsius) and thickness of sleeve checked.
7. One out of 50 joints coating or one coating out of every day production shall be tested to establish peel strength on steel and factory applied coating.