Protecting the tie-in joints of a highly corrosive brine pipeline
Engineers for a major midstream operator in Texas needed to transport highly corrosive brine through a 36-inch pipeline. The steel pipe was protected with a robust internal epoxy lining, but manually coating the interior of the welded tie-in joints would have required dangerous confined-space entry and added days to construction.
FlexSleeve® was selected for the project’s challenging tie-in joints. Its lightweight, flexible design allowed the sleeves to be handled and inserted into the pipe ends, even at 36 inches in diameter. A total of 25 tie-ins were completed on the 36-inch line, and the welds passed NDE examination.
The solution
The same project included 2 km of 16-inch pipeline constructed largely above ground on racks, with one FlexSleeve installed at each of its 200 welded joints.
By eliminating manual internal joint coating, the contractor saved several days of construction time and avoided dangerous confined-space entry. The pipeline was successfully pigged, inspected, and commissioned.
Project details
- Pipeline: 36-inch x 3 km buried line with 25 tie-ins
- Second line: 16-inch x 2 km, largely rack-mounted, with 200 welded joints
- Service: Highly corrosive brine
- Internal lining: Sherwin-Williams NovaPlate® 100% solids novolac epoxy
- LPS product: 25 36-inch FlexSleeves and 200 16-inch FlexSleeves
- Location/date: Texas, USA; pigged and commissioned February 2026
- Owner/contractor: Confidential
The FlexSleeve system protected the lined pipe at each weld zone while preserving familiar field construction and inspection practices.
Pigged, inspected and commissioned
- Line clearing: Bare polyurethane squeegee bullnose pigs swept construction debris from the line.
- Hydrostatic fill: The same pig type was run as an interface pig for a controlled, bubble-free fill.
- Dewatering: The pig was run again to displace test water after the hydrostatic test.
- Caliper inspection: A Winterhawk Digi-Cal caliper pig was run at 4,800 cfm and 40 psi head pressure to map the internal bore.
- Final cleaning: Oversized 38-inch bare foam swabs were run until the line met the cleanliness standard for service.
Every pig passed through the FlexSleeve® joint-diameter restrictions without adverse issues. The caliper tool identified a uniform, repeatable restriction at each FlexSleeve joint, confirming consistent joint geometry, and the pipeline was approved for service.
