Surface Preparation with Technologies for Subsea and Field Joint Coating

Originally published in 3R International, Special Edition 01/2019.

The integrity of subsea pipelines and the longevity of field joint coatings depend fundamentally on the quality of surface preparation applied at each girth weld. This technical article, published in 3R International in early 2019, examines the specific challenges of subsea and field joint surface preparation and how MontiPower's Bristle Blaster® and Cleantech Prepper technologies address them.

The Unique Demands of Subsea Surface Preparation

Subsea pipeline construction and maintenance involves surface preparation under conditions that are fundamentally different from onshore or plant environments:

• Laybarge operations: Field joints must be prepared and coated within the lay cycle — often 30 to 90 minutes per joint — creating time pressure that cannot be relaxed for logistical convenience
• Environmental restriction: Open-water blasting of any kind is environmentally unacceptable; abrasive media falling into the sea is prohibited in virtually all jurisdictions
• Confined workspace: Field joint stations on laybarges are compact, with limited space for equipment and workers
• Coating system requirements: Modern field joint coatings — heat-shrink sleeves, liquid-applied polyurethane, or FBE repair systems — have specific surface condition requirements that must be met for warranty coverage and performance assurance

Bristle Blaster® for Field Joint Preparation

The Bristle Blaster® was adopted for subsea field joint preparation precisely because it addresses each of these constraints simultaneously:

• Generates no abrasive waste — no environmental restriction on operation near or over water
• Compact and lightweight — fits within the space constraints of laybarge field joint stations
• Fast — experienced operators achieve Sa 2½ / SSPC-SP10 cleanliness and 65–85 µm Rz profile within the lay cycle time window
• Approved — major field joint coating manufacturers accept Bristle Blaster®-prepared surfaces for their products

The Cleantech Prepper: Automated Laybarge Field Joint Preparation

For high-volume deepwater and shallow water pipeline projects, manual Bristle Blaster® operation can become a throughput constraint. The Cleantech Prepper was developed specifically to resolve this — providing a mechanized, automated preparation system that integrates directly into the laybarge field joint workflow.

The Cleantech Prepper system:

• Fits around the pipe and rotates the Bristle Blaster® action around the full circumference automatically
• Provides consistent preparation quality regardless of operator skill or fatigue
• Includes integrated dust extraction — maintaining the cleanliness of the preparation and the working environment
• Achieves full-circumference preparation of a standard 12-metre joint section in a time compatible with high-production lay rates
• Has been deployed on major pipeline projects in the North Sea, Gulf of Mexico, and offshore Brazil

Coating System Approvals and Specification Support

The technical credibility of a preparation method in the subsea market depends not only on its physical performance but on formal recognition by coating system manufacturers. MontiPower has worked systematically to obtain coating manufacturer approvals for Bristle Blaster®-prepared surfaces used with field joint coating systems.

These approvals enable project engineers to specify Bristle Blaster® preparation with confidence that the coating manufacturer will honor their performance warranty — a critical requirement on major projects where field joint coating failure has significant long-term cost implications.

Conclusion

For subsea and field joint coating applications, the combination of Bristle Blaster® for manual operation and Cleantech Prepper for automated, high-volume deployment provides a complete, specification-compliant surface preparation solution that eliminates the environmental, logistical, and operational constraints of abrasive blasting.

MontiPower's technical team is available to support project engineers, coating contractors, and pipeline operators in designing surface preparation programs for specific project requirements. Contact us to discuss your subsea or field joint preparation needs.