Related
Propane Line, Patch and Valve Encapsulation
Overview
A nozzle off a 600mm propane header had experienced severe corrosion under insulation (CUI) and a leak had developed. While the line was live it would ice up, so this case required a short shut down in which to apply the Technowrap™ solution. To achieve a rapid cure, heat tapes were used to control the cure speed. The geometry and corrosion required a defect design of full circumferential wall loss over a 300mm length.
Scope
The line had the following specifications:
| Structure | 600mm header with nozzle |
| Surface Preparation | Sa 2.5 |
| Class Approval | N/A |
| Design Pressure | 1,740 kPa |
| Design Temperature | -42 0C to 650C |
| Application Temperature | 100C |
| Design Life | 5 years |
| Wrap Length | 550 mm |
| Pipe Diameter | 25 mm |
| Geometry | Wrap over valve, nozzle and header line |
| Corrosion Type | External |
| Defect Details | 300mm circumferential slot (through-wall) |
Solution
- Technowrap™ High Ambient (HA) with -750C capability
- The cure was controlled with heat tapes
- Filler material was used to cover valve and flange. The valve handle was removed to reduce the filler amount required
- The defect size was modelled to match the full section where filler was use
Benefits
- Rapid controlled cure to ensure limited production down time
- Flexibility to cover complex geometry and design according to ISO 24817
- Versatility by delivering a patch solution onto the main header line, instead of a full wrap which would have cost more and taken longer to apply
- Technowrap™ HA able to cover a wide temperature range from -7500C to 9000C
- Repair completed without hot works
