Field Joint Coatings for Pipeline

1. Field application of coal tar and asphalt enamel

This was applied in a manner similar to the coating of pipeline by wrapping hot enamel and fabric around the joint

2. Liquid applied field joint coatings (solvent free two pack liquid epoxy and polyureathane)

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3. Radiation cross-linked heat shrink sleeves

Traditionally, radiation cross-linked heat shrink sleeves were used for asphalt and coal tar enamel coated pipe as field joint coating. It is successful for field joint of line pipes coated with FBE, two or three layer polyethylene (PE)  recently. Some test of this field joint coating for FBE-polypropylene coated line pipe

4. FBE powder coating

FBE powder coating is also applied for field joint of line pipes coated with FBE,  two or three layer polyethylene (PE)

5. FBE-polypropylene

Normally, FBE-polypropylene is selected for line pipe with requirements of high mechanical damage resistance and operating under high temperature.  Therefore, the similar FBE-polypropylene field joint coating is also required. Normally, FBE is applied as the first layer. A number of types of FBE-polypropylene field joint coatings

• FBE-Sintered polypropylene copolymer

Will have limited coating film thickness (<1 mm) with porous in coating structure if the temperature is insufficient.

• FBE-Coextruded polypropylene sheet

PP-PP adhesive sheet wrapped on field joints, it is a time consuming process, however the it is close to the line pipe coatings.

• FBE-Injection moulded polypropylene

The most complicated and costly process, only utilised in offshore pipeline.

• FBE-Flame sprayed polypropylene copolymer

The most versatile process for field joint with large range of film thickness

• FBE-Coextruded polypropylene tape

This is a variation of FBE-Coextruded polypropylene sheet, which is more convenient in field application.

• Polypropylene heat shrink sleeve