Customer: Major North Sea Operator (Unmanned Production Platform)
Asset Type
Unmanned Offshore Production Platform
Location
North Sea
Working Medium
Refrigerant, Process Hydrocarbons, Methanol
Max Contained Pressure
21 bar
Flange Sizes
Ā½" ā 12"
Flange Classes
150#, 300#, 600#
Number of Flanges
127
Project Scope
Hot Bolting on live pipe systems, Integrity Assessment, MorSafeā¢ Clamp Deployment
After years of continuous operation in harsh North Sea conditions, the operatorās unmanned platform was showing accelerated fastener corrosion across more than 100 four-bolt flanges. Under the operatorās governing procedures, hot bolting of four-bolt or hydrocarbon-containing flanges is not permitted without verified additional restraint. With the asset carrying pressurised gases and liquids, the corrosion posed a real risk of bolt failure, and potentially dangerous leaks. The challenge was clear: restore flange integrity, reduce risk, and extend the life of the platform - without interrupting production.
Hydratight deployed a multi-disciplinary team of integrity engineers and bolting specialists to conduct a full assessment of the affected flanges and perform hot bolting on live pipe systems.
1. Comprehensive Data-Led Assessment
Using joint application surveys and a structured database approach, Hydratight catalogued key operating and mechanical parameters, including:
Flange alignment
Media type
- Line pressures and temperatures
- Corrosion condition and bolt condition
Engineering reviews were then cross-referenced with the operatorās hot-bolting certification requirements to confirm suitability for controlled bolt replacement.
2. Deployment of MorSafeā¢ Clamps for Safe Hot Bolting
Hydratight recommended its MorSafeā¢ restraint system for all applicable flanges.
The MorSafeā¢ clamp:
- Encases the flange to prevent any load release on the gasket
- Maintains joint integrity during bolt exchange
- Fits a wide range of geometries due to its compact profile
For this campaign, clamps were mobilised for flange sizes DN15 (Ā½") to DN300 (12") across classes up to 600#, handling pressures up to 21 bar.
3. Planned, Controlled, Zero-Disruption Execution
Forward planning between Hydratight and the operator ensured the highest-risk flanges received additional controls, while other flanges proceeded safely with MorSafeā¢ support.
The result: a streamlined, predictable, and fully compliant hot-bolting programme offshore.
Hydratight successfully upgraded all identified āat-riskā flanges with zero downtime and zero incidents, preventing an otherwise unavoidable shutdown. Key outcomes:
250 man-hours of shutdown avoided
Improved long-term asset integrity
Increased productivity through more flanges upgraded per shift
Reduced disruption to offshore operations
Complete adherence to client safety and procedural requirements
