Restoring a Leaking Chlorine Process Line Without Trenching
Overview
A major U.S. chemical manufacturer depended on a 4 inch underground carbon steel process line to deliver chlorine to a neighboring industrial facility. The pipeline extended approximately 4,200 feet across privately controlled property and marshy terrain. Multiple leaks created serious safety, environmental, product loss, and compliance concerns.
Motivo rehabilitated the existing pipeline from the inside using flexible fiber reinforced pipe, or FFRP. The project required only localized excavation at tight bends and was completed in four days without a plant shutdown.
The Challenge
The pipeline carried pressurized chlorine between two industrial facilities. Because the receiving facility depended on the line for an essential material, the plants needed to restore dependable delivery without creating a prolonged disruption to either operation.
The leaks presented risks beyond the value of the lost product. A release from a pressurized chlorine line can create significant worker safety and environmental exposure. Leaking process piping can also create concerns related to safety, environmental compliance, permitting, and continued operation.
The pipeline’s location made conventional excavation and replacement especially difficult. It ran underground for approximately 4,200 feet, crossed land the plants did not own, and passed through marshy areas. Wet and unstable soils would have increased the likelihood of trench sloughing, dewatering requirements, difficult soil handling, and environmental remediation.
Replacing the line conventionally would also have required extensive coordination with property owners and restoration of the disturbed areas. These conditions created significant uncertainty around the cost, schedule, and environmental impact of a traditional dig and replace project.
Why Point Repairs Were Not Enough
The carbon steel pipeline had developed multiple leaks along its length. Repairing the line one location at a time would have required repeatedly locating defects, excavating through difficult terrain, repairing the pipe, and restoring the disturbed ground. Individual repairs would also have left the remaining deteriorated pipeline in service. The plant needed a solution that addressed the full line rather than relying on a continuing series of temporary repairs.
The Solution
Motivo cleaned the existing pipeline and installed a factory manufactured FFRP liner inside the carbon steel host pipe. Unlike cured in place pipe, FFRP arrives at the project site fully manufactured and does not require resin curing inside the pipeline. The liner remains flexible during installation, allowing it to be folded and pulled through long sections of existing pipe.
The 4,200 foot installation was completed in multiple pulls. Tight 90 degree bends could not be negotiated by the liner, so Motivo performed localized excavations at those locations. These access points allowed the liner to be installed in sections without trenching across the full route.
Once each section was pulled into position, the liner was inflated and connected to the existing piping system using engineered termination fittings. The installed liner created a new pressure barrier inside the original carbon steel pipe, allowing the existing pipeline to remain in the ground.
The FFRP system included an inner layer selected for compatibility with the material being transported, a reinforced layer designed for the required operating pressure, and a durable exterior layer. This construction allowed the liner to safely convey the chlorine while using the existing host pipe for external support.
The Result
Motivo rehabilitated approximately 4,200 feet of leaking chlorine process line in four days. The work was completed with only localized excavation at the bends, no continuous trenching, and no plant shutdown.
The project restored dependable chlorine delivery between the facilities and eliminated the active leak condition. This substantially reduced the worker safety, environmental, product loss, and compliance risks associated with the deteriorated line.
Motivo completed the rehabilitation for approximately $800,000. Conventional excavation and replacement was estimated to cost approximately $5 million. The trenchless approach therefore saved the manufacturer approximately $4 million while also reducing the schedule, environmental impact, and uncertainty associated with excavation.
The FFRP liner was designed to provide a service life of 50 years or more, giving the plant a long term solution rather than a series of temporary repairs.